Canola eng -final - Overberg Agri manual.pdf · 5.3 Plant density and row ... stages is determined...

TABLE OF CONTENTS

1. THE CANOLA PLANT 1

1.1 Origin1.2 Growth stages of the canola plant

2. GROWTH REQUIREMENTS AND PRODUCTION POTENTIAL 3

2.1 Climate2.2 Soil requirements and production potential

3. CANOLA AS ROTATION CROP 5

3.1 General3.2 Benefi ts of canola as rotation crop3.3 Crop rotations for the Western and Southern Cape

4. CHOICE OF CULTIVARS 9

4.1 Cultivar types4.2 Recommended cultivars

5. ESTABLISHING CANOLA 15

5.1 Seed quality and seed treatment5.2 Planting time5.3 Plant density and row spacing5.4 Planting method and planting depth5.5 Preparing the seedbed

6. FERTILISATION 19

6.1 Nitrogen6.2 Phosphorous6.3 Potassium 6.4 Sulphur6.5 Other plant nutrients

7. WEED CONTROL 25

7.1 General7.2 Control strategies and herbicides

8. DISEASES AND DISEASE CONTROL 27

8.1 Seedling dieback (Fusarium spp., Pythium spp., Rhizoctonia solani)8.2 Blackleg (Leptosphaeria spp./Phoma lingam)8.3 Stem rot (Sclerotinia sclerotiorum)

9. INSECT PESTS AND CONTROL 31

9.1 Insect pests9.2 Snails and isopods9.3 Control measures9.4 Important warning with regard to bees

10. HARVESTING CANOLA 39

10.1 Harvest techniques10.2 Time of harvest10.3 Harvest losses

11 UTILISATION OF CANOLA 43

11.1 Human nutrition11.2 Animal feed11.3 Biofuel

PREFACE

This year is the tenth year since the PRF became actively involved in the promotion of canola in South Africa and specifi cally in the Western Cape province. It therefore is with great joy and gratitude that the PRF has granted its full fi nancial support to the compilation and publication of this complete canola guide, which is regarded as a special milestone in the history of this young industry in South Africa.

The local production of protein for animal consumption in South Africa is the most important objective of the PRF. Canola is regarded as the only source of this protein that can currently be successfully produced in the Western Cape, and the PRF wishes to express its confi dence that this combined effort of a number of excellent researchers and experts in various fi elds will indeed form the basis for further progress in and extension of the canola industry in South Africa.

Together with the acknowledgement of those who made contributions to the publication of these production guidelines and which is contained elsewhere in this publication, the PRF would also like to express its gratitude and appreciation to Dr Jos de Kock, member of the PRF Board, for his guidance on behalf of the PRF in this publication, and to Prof André Agenbag, for the compilation of the production guidelines and for his particular attempt to ensure that this glossy publication is not only special, but also an extremely valuable reference work for all those involved in the canola industry.

GJH SCHOLTEMEIJERCHAIRPERSON

1. THE CANOLA PLANT1.1 Origin

The majority of the canola cultivars that are being cultivated in the Western Cape belong to the species Brassica napus. The name “canola” is derived from “Canada and oleic acid” and is defi ned as: “An oil that must contain less than 2% erucic acid, and the solid component of the seed must contain less than 30 micromoles of any one or any mixture of 3-butenyl glucosinolate, 4-pentenyl glucosinolate, 2-hydroxy-3-butenyl glucosinolate, and 2-hydroxy-4-pentenyl glucosinolate per gram of air-dry, oil-free solid.”

This means that it contains a healthy oil that is low in polyunsaturated fatty acids. It is therefore approved by the Hearth Foundation for general use as its high percentage of omega 3-fatty acids leads to a decrease in LDL cholesterol levels.

1.2 Growth stages of the canola plant

The description of the different growth stages of the canola plant is much more complicated than that of winter cereals. The reason for this is that the different stages cannot be separated from each other as clearly as is the case with winter cereals, nor do they follow chronologically on one another, but rather overlap partially because of the indeterminate growth pattern of the canola plant. The duration of the different stages is determined by factors such as temperature, water supply, light, nutrition and cultivar and can therefore vary considerably. Nevertheless, the following growth stages can be distinguished:

Germination and emergence

Before germination can take place, the seed fi rst needs to absorb suffi cient water. If favourable soil water conditions and soil temperatures of approximately 20°C are present, the seed coat will burst open after about 17 hours and the radicle will appear. After 7 – 10 days the young seedlings should make an appearance as two heart-shaped cotyledons. The canola seed is very small and therefore contains little reserves. It thus is important that this stage does not last too long. In contrast to that of cereals, the growth tip of the canola plant is already visible above the soil surface at this stage, and the seedling is therefore very vulnerable to insect damage and wind-blown sand particles.

Production of leaves

The appearance of the fi rst true leaf about 4 – 8 days after emergence is a sign that the leaf production stage has started. Because leaf initiation takes place much faster than leaf emergence, the canola plant displaysa rosette pattern of growth, with the youngest leaves in the centre and the oldest leaves on the outside. Rapid leaf development is essential to improve the plant’s ability to compete with weeds and also because the early development of a high leaf area index (square metre of leaf area per square metre of soil surface) is associated with a high yield potential. However, the optimal leaf area index will be determined by the yield Photo left: Swathed canola

2 CANOLA MANUAL

potential (soil and climate) for a specifi c production area.

Stem elongation

Stem elongation begins when the distance between consecutive leaves on the stem is greater than the thickness of the stem. This stage points to a drastic increase in dry mass and an associated increase in the nutritional requirements of canola.

Flower initiation

Flower initiation starts with the development of the primary peduncle from the growth tip in the middle of the leaf rosette. This stage is accelerated by high temperatures and, to a lesser extent, by increasing day length. Although the leaf area index probably reaches the maximum at this stage, the maintenance of leaf surface hereafter is very important for pod set, grain fi lling and the oil content of the seed.

Anthesis

Anthesis begins when the lowest fl ower bud on the main rachis opens. As time passes, fl owers that are higher on the main rachis and on its lateral branches start opening. Although canola is 70 – 80% self-pollinating, pollen is also dispersed by wind and insects. Unfavourable conditions, such as water stress and temperatures > 30°C, can also impair pollination.

The fl owering period of canola cultivars with a determinate growth pattern is limited, but in the case of cultivars with an indeterminate pattern of growth the fl owering period will continue until environmental conditions terminate fl ower formation. Although the period of fl owering can vary greatly on the basis of the cultivar being planted, planting time and growth conditions, the largest pods and seeds and therefore also the greatest contribution to yield will be made by the fl owers on the main rachis and the fi rst fl owers on the lateral branches.

Pod and seed development

During the pod development phase, which lasts about 14 – 16 days, the pod and seed coat are formed. This is followed by the seed development phase, during which carbohydrates, proteins and fi nally oil are deposited in the seed. The oil content will therefore be determined right at the end and premature ripening will have a negative effect on the oil content. Harvest indexes for canola vary between 15 and 35% and therefore generally are lower than for winter cereals.

CANOLA MANUAL 3

2. GROWTH REQUIREMENTS AND PRODUCTION POTENTIAL

2.1 Climate

Canola is a temperate crop and the duration of the different growth stages will therefore be shortened by high temperatures. Moderate temperatures of 20 – 25°C are optimal for photosynthesis and the accumulation of dry material. Although 5°C is regarded as the minimum growth temperature for canola, germination is considerably delayed by low temperatures, and temperatures of 15 – 20°C are optimal for germination. Temperatures > 30°C can be detrimental to the pollination of the fl owers and will shorten the stage during which the pods and seeds develop to such an extent that both yield and quality can be impaired. The effect of high temperatures is worsened by concomitant water stress conditions. Because the seeds of canola are very small and there consequently is less contact with soil particles, high soil water contents are required for successful germination in contrast to what is required for wheat. Once it has been established, canola roots can penetrate the soil to a depth of 100 cm by way of its taproot system to absorb water and nutrients, and it can therefore withstand dry periods better than wheat. Maximum evapotranspiration (water consumption) of as much as 8 mm per day during the fl owering stage compares well with that of wheat, however, and photosynthesis is usually impaired if > 75% of the plant-available water content is removed from the soil.

Rainfall of 300 mm and more between April and October is ideal for seed yields of 2 tons and more per hectare. With rainfall of 200 mm, the yield potential drops to about 1 ton per hectare. Rainfall distribution is very important, however, and a long rainy season with suffi cient rain during the pod and seed development stages is very important. Long-term rainfall averages for the Western and Southern Cape are given in Figure 1.

2.2 Soil requirements and production potential

Canola prefers well-drained soil with a high potential for wheat production. Light sandy soils should preferably be avoided. The soil should not be prone to crusting and should also not be subject to wind erosion. Cool, stony soils on southern slopes produce good seed yields. Soil with a pH of between 5 and 7 (KCl) and acid saturation of no more than 10% is ideal for canola. Although fertilisation with P and K should be adjusted on the basis of soil analyses, an effort is made to achieve a content of approximately 36 ppm P (citric acid) or 24 ppm P (Bray 1) and > 60 ppm K (Bray 1). As in the case of wheat, canola is also moderately tolerant to alkaline soil. Figure 2 illustrates the yield potential of canola in the different regions in the Western and Southern Cape. The yield potential was calculated on the basis of the soil type and rainfall.

4 CANOLA MANUAL

Figure 1. Average rainfall from April to October for the Western and Southern Cape.

CANOLA MANUAL 5

3. CANOLA AS ROTATION CROP3.1 General

Crop rotation entails the successive cultivation of different crops on the same soil over the years. Although some defi nitions propose a fi xed sequence of crops, a more adaptable approach is followed in the Western and Southern Cape to make provision for large differences in farming units, and even for differences between respective fi elds. If canola is included in systems, its frequency is usually determined by the occurrence of the disease blackleg.

In order to prevent this disease, it is recommended that canola should not be planted on the same soil more often than every fourth year. Since blackleg spores can also be spread by wind, it is important to have a downwind distance of at least 500 m from the previous canola plantings. During the planning of a suitable crop rotation system that includes canola, attention thus needs to be paid to both where and when canola is to be cultivated.

Figure 2. Yield potential of canola in the Western and Southern Cape in relation to soil and climatic conditions.

6 CANOLA MANUAL

3.2 Benefi ts of canola as rotation crop

i) Improved grain yields

The inclusion of canola in a crop rotation system usually leads to an increase in the yield of the subsequent cereal crops. It appears from the table below that, in comparison to a wheat monoculture system, the wheat yields over a fi ve-year period on Langgewens Experimental Farm increased by 20% in the fi rst wheat year after canola. The increase in wheat yield in the second and third year after canola was 11% and 8% respectively. In a system where canola is cultivated only one year out of every four, the yield of wheat in the remaining three years is therefore increased by an average of 13%. If lupins are included in the rotation, this research has shown wheat yields after canola to increase by 29 – 32%.

Five-year average yield of wheat in the fourth year of the following rotation systems on Langgewens Experimental Farm in the Swartland production region

Crop rotation Average yield(kg/ha)

Increase in yield(%)Year 1 Year 2 Year 3 Year 4

Wheat Wheat Wheat Wheat 2658 0

Canola Wheat Wheat Wheat 2879 8

Wheat Canola Wheat Wheat 2963 11

Wheat Wheat Canola Wheat 3180 20

Lupins Canola Wheat Wheat 3078 16

Wheat Lupins Canola Wheat 3431 29

Lupins Wheat Canola Wheat 3509 32

ii) Reduction in diseases

By including a non-cereal crop such as canola, which does not serve as a host for pathogens that cause diseases affecting wheat, the disease chain is broken and diseases are reduced. Various studies have shown that canola also has a bio-fumigation effect that suppresses diseases.

iii) More effective weed control

The inclusion of canola in a rotation with cereal crops increases the variety of herbicides that can be used, as canola is a broadleaf crop (in contrast to wheat and barley as cereal crops) and both triazine- (TT type) and imazamox- (Clearfi eld type) tolerant canola cultivars are available. By alternating the use of the greater variety of available herbicides, the development of herbicide-resistant weeds such as ryegrass (Lolium rigidum) can be controlled. If soil-active (residual) herbicides are used, producers should note the withholding periods for

CANOLA MANUAL 7

sensitive crops very carefully.

iv) Improved root system

The canola plant develops a tap-root system that can penetrate the soil to a depth of 1.0 metre. When these roots die and decay, channels are formed in the soil. Particularly in the case of systems of reduced tillage, this biological ploughing action of canola can give rise to an improved root system in the subsequent cereal crops.

v) Planters and harvesters are used more effectively

Because canola is planted and harvested earlier that wheat, and the same planters and harvesters can be used, this equipment is utilised much more effectively.

vi) Better distribution of the fi nancial risk

Economic evaluations of long-term crop rotation trials have shown that the inclusion of canola in crop rotation systems increases the returns on the capital investment when compared with monoculture systems using only wheat.

vii) Improved adaptability of crop rotation systems that include canola

In contrast with other crops, canola can be included before or after cereals in a crop rotation system.

3.3 Crop rotations for the Western and Southern Cape

The following short rotation systems are used in the Western Cape:

Cash crop rotations: Wheat / lupins / wheat / canola Wheat / wheat / oats / canola

Crop/pasture rotations: Medics / wheat / medics / canola Medics / medics / wheat / canola

8 CANOLA MANUAL

Both long and short rotation systems can be used in the Southern Cape, as follows:

Long rotation systems:5 year lucerne / wheat / wheat / canola / wheat / wheat

luserne – use if root diseases are not a

problem and if additional disease control is acceptablec

5 year lucerne / wheat / canola / wheat / wheat / canola luserne

– use if blackleg is not a problem.

5 year lucerne / canola / wheat / lupins / wheat / canola lluserne

– use only if broadleaved weeds can be controlled in canola after lucerne.

5 year lucerne / wheat / canola / wheat / lupins / wheat luserne

5 year lucerne / wheat / lupins / wheat / canola / wheat luserne

7 year lucerne / wheat / barley / barley / canola / wheat / barley / barleyluserne

– however, be prepared to spend more money on chemical disease control in cereals.

Short cash crop rotations: Wheat / barley / lupins / wheat / barley / canolaWheat / lupins / wheat / canola

Short crop/pasture rotations:

Medics / wheat / medics / canolaMedics / medics / wheat / canola

CANOLA MANUAL 9

4. CHOICE OF CULTIVARS

4.1 Cultivar types

Cultivars are classifi ed primarily on the basis of the length of their growth season and this can vary from ultra-short (< 78 days to fl owering) and short (78 – 85 days to fl owering) to medium (86 – 95 days to fl owering) and long growth season cultivars.Classifi cation can also be done on the basis of herbicide tolerance. Conventional types have no specifi c tolerance; TT types are tolerant of triazine herbicides, while IT (Clearfi eld) types are tolerant of amazamox herbicides. Hybrid cultivars could lead to signifi cant increases in yield, but because they generally do not produce fertile seeds, new seed will have to be purchased every year. Resistance to disease, and particularly to blackleg, is an important cultivar property and, as such, is one of the most important selection criteria for new cultivars. The consequence is that all new cultivars have good resistance.

4.2 Recommended cultivars

The results of cultivar trials done by the Department of Agriculture: Western Cape in the Southern Cape and Swartland in 2007 are summarised in the tables below.

Canola in crop rotation with lupins

10 CANOLA MANUAL

TABLE 1SOUTHERN CAPE SEED YIELDS (kg/ha)

PLANTING DATE

Tyger-hoek 1

Tyger-hoek 2

Napier Cale-don

Rivers-dal

2007 2006 2005 2006/ 07

30/04 sd 25/05 sd 03/05 sd 04/05 sd 19/04 sd Ave. Ave. Ave. Ave..

Muster

2085 ab 1622 ab 2178 ab 2701 a 2403 a 2192 1

Hyola 61

1950 abcd

1894 a 2164 ab 2259 bcd 2558 a 2165 2 2354 5 2060 3 2259 2

Opal

2158 a 1827 a 2167 ab 2371 b 2184 a 2141 3 2412 2 2277 1

44C11

1754 cdefg

1409 bc 2191 a 2445 ab 2615 a 2083 4 2353 6 2090 2 2218 5

Outback

1958 abc

1570 ab 1866 bcd

2443 ab 2440 a 2055 5 2213 9 1900 4 2134 8

Spectrum

1673 cdefg

1554 ab 2242 a 2431 ab 2371 a 2054 6 2411 3 2220 1 2233 4

44Y06

1713 cdefg

1628 ab 2099 abc

2275 bcd

2450 a 2033 7 2465 1 2249 3

Jade

1858 bcde

1585 ab 2229 a 2320 bc 2104 a 2019 8 2275 8 2147 7

Comet

1482 gh 1686 ab 1421 fe 2027 cdefg

2316 a 1786 13 2116 12 1830 5 1951 10

Average

1845 1642 2062 2364 2382 2059

TT Average 2006 2007 2006 / 07

Thunder

1803 bcedf

1559 ab 1845 dc 2206 bcde

2481 a 1979 9 1870 16 1720 7 1924 11

CANOLA MANUAL 11

Tyger-hoek 1

Tyger-hoek 2

Napier Cale-don

Rivers-dal

2007 2006 2005 2006/ 07

TT Average 2006 2007 2006 / 07

Cobbler

1617 efg

1368 bcd

1939 abcd

1967 defg

2339 a 1846 12

ATR Stubby

1655 defg

1419 bc 1466 fe 1909 efg

2313 a 1752 14 1781 17 1700 8 1767 14

Tornado

1546 fg 1016 d 1649 de 1838 g 2326 a 1675 15 1910 14 1610 10 1793 13

Banjo

1243 hi 1126 cd 1193 f 1501 g 2173 a 1447 17

Average

CI Average 2006 2007 2006 / 07

45Y77

1533 fg 1745 ab 1698 de 2294 bc 2491 a 1952 10 2397 4 2175 6

44C73

1640 efg

1394 bcd

2012 abc

2179 bcdef

2391 a 1923 11 2008 13 1760 6 1966 9

Rocket CL

1640 i 1208 cd 1467 fe 1879 fg 2294 a 1698 16 2138 11 1620 9 1918 12

Average

1605 1449 1726 2117 2392 1858

Trial Average

1688 1501 1872 2179 2368 1922

Lsd:298.5

Lsd:380.4

Lsd:312

Lsd:308.5

Lsd:650.7

Cv:15.2

Cv:21

Cv:16.5

Cv:17.7

Cv:8.5

sd: Statistical difference – cultivars followed by the same letter do not differ signifi cantly from one another.

Lsd – lowest signifi cant difference at 95% confi dence level, Cv – coeffi cient of variation

12 CANOLA MANUAL

TABLE 2SWARTLAND SEED YIELDS (kg/ha)

Lang- gewens 1

Lang-gewens 2

Darling Philadelphia 2007 2006 2005 2006 / 07

PLANTING DATE

08/05 sv 22.05 sv 11.05 sv 11.05 sv Ave. Ave. Ave. Ave.

44Y06

3440 a 2318 ab

c

3541 a 3307 a 3151 1 2496 5 2824 1

Opal

3034 ab 2688 a 3480 ab 2314 efgh

2879 3 2419 7 2649 4

44C11

2897 bc 2475 abc

3152 bcd

2966 abc

2872 4 2534 3 2380 4 2703 3

Jade

2791 bc 2534 ab 3263 abc

2666 bcdef

2813 5 2352 8 2583 5

Spectrum

2866 bc 2437 abc 2948 cde

2619 cdefg

2718 6 2292 10 2630 2 2505 6

Muster

2548 bcd

1909 ed 3202 abcd

2720 bcde

2595 7

Outback

2894 bc 2110 cde

3095 cd 1916 h 2504 10 2435 6 2140 5 2469 7

Hyola 61

2067 edf 1839 ed 3099 cd 2411 defg

2354 13 2500 4 2700 1 2427 8

Comet

2029 ef 2227 bcd

2702 efg

2270 fgh

2307 14 2307 9 2480 3 2307 9

Average

2730 2282 3165 2577 2736

CANOLA MANUAL 13

TT Average 2006 2007 2006 / 07

Thunder

2504 cde 2391 abc 2471 gh 2195 gh 2390 11 1761 17 1880 9 2076 12

Tornado

2756 bc 1801 e 2672 efgh

2229 fgh

2365 12 1765 16 1740 10 2065 13

Cobbler

1790 f 1791 e 2512 fgh

2233 fgh

2082 15

Banjo

1713 f 1077 f 2321 h 1456 i 1642 16

Stubby

407 g 596 g 1990 gh 1474 i 1117 17 1837 15 1990 7 1477 14

Average

1834 1531 2393 1918 1919

CI Average 2006 2007 2006 / 07

45Y77

3430 a 2558 ab 3260 abc

3061 ab 3077 2 2555 2 2816 2

44C73

2430 cde 1814 e 3031 cde

2793 bdc

2517 8 2041 12 1980 8 2279 10

Rocket CL

2692 bc 2211 bcd

2873 def

2264 fgh

2510 9 2018 14 2090 6 2264 11

Average

2851 2194 3055 2706 2701

Trial Average

2488 2046 2918 2406 2464

Lsd:519.4

Lsd:391.7

Lsd:374

Lsd:441.5

Cv:10.9

Cv:9.8

Cv:24.9

Cv:12.5

sd: Statistical difference - cultivars followed by the same letter do not differ signifi cantly from one another.Lsd – lowest signifi cant difference at 95% confi dence level , Cv – coeffi cient of variation

The latest information will appear on the PRF web page (www.proteinresearch.net) every year.

TABEL 2 SWARTLAND SAADOPBRENGSTE (KG/HA)

LANG- SV LANG- SV DARLING SV MALMES- SV GEMID- GEWENS I GEWENS II BURY DELD Hyola 75 2472 abcd 2523 abc 2838 a 2628 abc 2615 1 45Y77 2463 abcd 2529 abc 2577 abc 2651 ab 2555 2 44C11 2638 a 2612 abc 2508 abc 2376 abcde 2534 3 Hyola 61 2591 abc 2183 abcd 2700 ab 2525 abcd 2500 4 44Y06 2604 ab 2260 abcd 2433 abcd 2686 a 2496 5 Outback 2600 ab 2465 abc 2338 abcde 2336 abcde 2435 6 Opal 2371 abcde 2796 a 1973 cdef 2536 abcd 2419 7 Jade 2235 def 2735 ab 2146 bcdef 2293 abcde 2352 8 Comet 2325 bcde 2138 bcd 2067 bcdef 2696 a 2307 9 Spectrum 2280 de 2447 abc 2164 abcdef 2277 abcde 2292 10 45C75 2332 bcde 2079 cd 2513 abc 2110 cde 2258 11 44C73 2248 def 2202 abcd 1690 def 2023 de 2041 12 45C05 2113 efg 2131 bcd 1870 def 2001 e 2029 13 Rocket CL 2290 cde 1632 d 2027 cdef 2121 cde 2018 14 ATR Stubby 1916 g 1698 d 1576 efg 2160 bcde 1837 15 Tornado TT 1857 g 1747 d 1432 fg 2026 de 1765 16 Thunder TT 1953 fg 1776 d 1431 fg 1885 e 1761 17 K2 06\01 1202 h 814 e 887 g 1154 f 1014 18 Gemiddeld 2249 2154 2065 2249 2179 KV (%) 8.1 17.57 19.57 14.03 KBV (0.05) 302.66 628.21 661.83 523.95 Clearfi eld 45Y77 2463 abcd 2529 abc 2577 abc 2651 ab 2555 45C75 2332 bcde 2079 cd 2513 abc 2110 cde 2258 44C73 2248 def 2202 abcd 1690 def 2023 de 2041 Rocket CL 2290 cde 1632 d 2027 cdef 2121 cde 2018 Triasien tolerant ATR Stubby 1916 g 1698 d 1576 efg 2160 bcde 1837 Tornado TT 1857 g 1747 d 1432 fg 2026 de 1765 Thunder TT 1953 fg 1776 d 1431 fg 1885 e 1761 TT&CL Gem. 2151 1952 1892 2139 2033.7

5. ESTABLISHING CANOLA

5.1 Seed quality and seed treatment

Only certifi ed seeds of which the seed vigour, purity and quality are guaranteed should be planted. The use of own seed or “farm seed” from co-producers is not recommended. Own or “farm seed” can germinate more weakly, therefore giving rise to lower yields and even a product with a poorer quality that is not acceptable to the buyers. Since canola is 20 – 30% cross-pollinated, it can happen that cultivar purity declines rapidly. Own seed also poses the threat of contamination with weeds such as wild mustard, since their seeds do not differ much. Canola cultivars in South Africa are registered under the Plant Breeders’ Rights Act, which prohibits the sale of own seed and subjects it to penalties.

Since canola seedlings can be damaged by a variety of fungal diseases and insects, chemical treatment of the seed with fungicides and insecticides can be benefi cial, as is evident from the table below. Seed that is distributed by registered seed dealers has usually been treated. Agents mentioned in the table are not registered for use on canola. However, Cruiser has been submitted and its registration is expected.

Infl uence of seed treatment with different doses (X = recommended dose) of two chemicals and planting density (kg ha-1) on the establishment (plants m-2) of Canola at different localities

Seed treatment LanggewensKg seed ha -1

3 7 9 Ave

RoodebloemKg seed ha -1

3 7 9 Ave

ElsenburgKg seed ha -1

3 7 9 Ave

Control

SA Comb 0.5 XSA Comb 1.0 XSA Comb 2.0 X

Cruiser 0.5 XCruiser 1.0 XCruiser 2.0 X

37 44 60 47

39 48 67 5139 51 75 5538 53 60 50

46 53 71 5643 58 75 5942 53 70 55

50 75 80 68

48 77 94 7351 87 88 7546 88 94 76

54 75 95 7554 63 90 6956 74 88 72

42 57 70 56

38 58 54 5041 58 62 5449 52 59 53

41 55 62 5339 47 63 5040 61 76 59

Ave 40 51 68 53 51 77 89 72 41 55 64 53

SA Comb = combination of thiram, metalaxyl, imidachloprid and iprodione; Cruiser = thiamethoxam, fl udioxonil and metalaxyl

Photo left: Canola infl orescence

16 CANOLA MANUAL

5.2 Planting time

Since the cultivars that currently are planted mostly have an indeterminate infl orescence, the production of fl owers, pods and eventually also seed will continue as long as growth conditions are favourable. Yields therefore usually show a good relationship with the length of the growing season. Early planting times promote high yields and canola can be planted in the Western and Southern Cape as early as in the middle of April, as long as there is suffi cient soil moisture.

5.3 Planting density and row spacing

The ideal plant density for canola is 50 to 80 plants per square metre. To obtain this plant density, 4 to 6 kg seed per hectare are required. If planters are used for establishment or if hybrid cultivars are sown, the sowing density can be reduced to 3 to 4 kg per hectare. As is apparent from the table below, optimal planting densities can differ over years and between localities. Although, according to the data below, yield can decrease on average by only 1 –2% per 2.5 cm increase in row width, row widths should not be more than what are needed to handle the crop residue. Row widths of 200 – 250 mm are therefore recommended.

Infl uence of row width and planting density on canola yield

Row width Planting density(mm) (kg ha-1)

Langgewens2001 2002 2005

Roodebloem2001 2002 2003 2004 2005

170 4 6 8

724 1089 1844 906 1224 1752 989 1242 1883

1621 1592 1465 1448 1920

1817 1691 1403 1714 1974

1702 1810 1679 1718 1901

Ave 873 1185 1826 1713 1698 1515 1627 1932

225 4 6 8

827 1046 1657

825 1044 1695

826 1229 1705

1545 1339 1503 1630 2101

1294 1503 1756 1741 2045

1614 1687 1359 1686 1955

Ave 826 1106 1686 1484 1509 1539 1687 2034

340 4 6 8

809 1151 1663823 1054 1749837 1130 1679

1260 1245 1739 1339 19861391 1407 1529 1445 18781187 1601 1607 1323 1989

Ave 823 1112 1696 1279 1418 1625 1369 1951

CANOLA MANUAL 17

5.4 Planting method and planting depth

It is very important that canola seedlings emerge from the soil at the same time to ensure a uniform stand. Uniform emergence eventually ensures uniform ripening with minimum seed losses during harvest. The best results are obtained with a uniform planting depth in moist soil. Care should be taken that the seeds are not planted too deep, since this will delay emergence and lead to a lower yield potential. The longer seedlings take to appear above the soil surface, the larger is the risk for seedlings to die as a result of disease pathogens. In general, therefore, canola is planted more shallowly than wheat. If it is planted early, canola can be planted at a depth of 2 to 3 cm. When canola is planted later, the soil is colder and planting should be shallower (1 to 2 cm). It is very important that the seed is placed in moist soil.

Canola can be established successfully with a variety of implements, as long as the following requirements are met:

Place the seed at a uniform depth on a fi rm, moist seedbed.

Spread the seed evenly in the planting row, as well as across individual rows.

The seeds should not be placed in direct contact with fertiliser.

Cover the seed with soil to the desired depth and compact it.

5.5 Preparing the seedbed

Canola prefers a fi rm and level seedbed with suffi cient depth in the root bed for maximum root development. If the soil is tilled in advance, the aim should be to create the abovementioned seed and root bed that is free of weeds. If the soil is compacted and plough pans had developed, these should be removed by deep tillage. If a ripple or wave effect is obtained with tine tillage or when the seedbed is very loose, a drag bar, harrow or roller should be used to ensure a level, fi rm seedbed. The seedbed should be tilled as early as possible, preferably before April, so that early weeds can germinate. Shallow tillage covers weed seeds and stimulates germination and emergence. During the fi nal seedbed preparation, late emerging weeds and volunteer cereals are controlled and eliminated mechanically or chemically. Excessive or deep tillage should be avoided, since it will dry out the soil.

As is evident from the table below, systems of minimum and no tillage can also be applied successfully if the application of N is suffi cient. Alternating between tillage methods to prevent the development of compaction layers appears to produce very good results.

18 CANOLA MANUAL

Infl uence of N fertilisation and method of tillage on the yield of canola in the Swartland production region (2001-2005)

N – Application rates (kg ha-1)Tillage method 20 60 100 Ave

Conventional mouldboard plough 980 1145 1261 1129

Conventional Tine* 1017 1078 1351 1149

Minimum **(Min) 613 909 1035 852

No Tillage(NT) 852 955 1198 1002

Min / NT*** 969 1129 1381 1160

Min / 2 x NT 860 1281 1364 1168

Min / 3 x NT 759 1211 1445 1138

Ave 864 1101 1290 1085

* Deep (150 mm) tine followed by a shallow (75 mm) tine ** Shallow (75 mm) tine followed by pre-planting herbicide sprays*** Minimum and no tillage are alternated All treatments were planted with a tine implement equipped with knifepoint openers

Canola can be planted directly

CANOLA MANUAL 19

6. FERTILISATIONIn order to obtain a better understanding of the nutritional requirements of canola, it is important to note the comparative removal of the most important nutrients by canola and wheat.

Nutrient removal fi gures of the most important nutrients by canola in comparison to wheat (kg ha-1 removed per ton of grain)

Crop Nitrogen Phosphorus Sulphur

Canola 40 7 10

Wheat 21 3 1.5

Per ton of grain produced, canola therefore removes much more nutrients from the soil than wheat and its fertilisation requirements will therefore also be higher. In order to make a meaningful recommendation for canola, it is necessary to undertake a full soil analysis that includes both the carbon percentage and stone fraction.

6.1 Nitrogen

Just as in the case of wheat, rainfall, crop rotation, soil texture, nitrogen content, planting date, method of establishment and the yield objective should be taken into consideration when the nitrogen requirement is determined.

Nitrogen fertilisation guidelines for canola

Area and Yield Kg N per ha for Canola after rainfall

rainfall PotentialLucerne*

One-year legume system

Cereal stubble***

SOUTHERN CAPE(65% rainfall)) < 350 mm350 - 425mm425 - 500 mm > 500 mm

1.25 t ha-1

1.5 t ha-1

2.0 t ha-1

2.5 t ha-1

1010 – 2020 – 3040 – 50

25 – 3030 – 3540 – 4550 – 55

30 – 5050 – 7060 – 9080 – 110

SWARTLAND(83% winter rainfall) < 325 mm325 - 425 mm > 425 mm

1.25 t ha-1

1.75 t ha-1

2.50 t ha-1

50 – 70**

70 – 90 90 – 110

70 – 90 90 – 110110 – 130

* Grazing in which grasses are controlled. ** Higher value of application on lighter soils. *** Includes minimum and no tillage..

20 CANOLA MANUAL

Nitrogen during establishment

Preferably use nitrate-based nitrogen or urea placed away from the seed.

Planter (band placed at seed) – 20 kg N ha-1 when sowing in 25 cm row widths.

Scale down to 15 – 18 kg N ha-1 for wider rows.

Broadcast – not more than 30 kg N ha-1 when sowing where rainfall < 350 mm.

Maximum of 40 kg N ha-1 when sowing where rainfall > 350 mm.

Nitrogen topdressing

The distribution of nitrogen fertilisers during the growth period of the canola crop has to be given special attention. In general, two topdressings are recommended. The fi rst topdressing must take place 30 to 40 days after emergence. On heavier soils it is recommended that at least ± 65% of the total topdressing should already be applied at 30 days after emergence. On lighter soils, which tend to leach easily, two equal topdressings are recommended, viz. at 30 days after emergence and at the onset of stem elongation. If there is more than usual rainfall till about 60 to 70 days after emergence, the second topdressing should be increased correspondingly. If silage canola is being produced, it is recommended that 40 kg N ha-1 be broadcast when sowing and 50 to 60 kg N ha-1 be given as topdressing at 30 to 40 days after emergence.

Canola under irrigation requires approximately 150 kg N ha-1, which should be applied as follows:

30 kg N ha-1 – broadcast at planting – 20 kg N ha-1 if band placed40 kg N ha-1 – 20 days after emergence40 kg N ha-1 – 30 days later40 kg N ha-1 – 50% fl ower bud formation

6.2 Phosphorus

A soil value of 36 mg kg-1 (citric acid) or 24 mg kg-1 (Bray 1) is taken as point of departure. At lower or higher soil analyses, adjustments are made taking into account the factors that determine yield potential. A maintenance fertilisation of 10 kg P ha-1 is recommended. In cereal crop rotation systems, applications can be adjusted downwards by 30%.

Conventional seedbed preparation of canola fi elds

CANOLA MANUAL 21

Phosphorus fertilisation guidelines for canola in a legume crop rotation system.

Phosphorus status of the soil (mg kg-1) P-fertilisation

Citric acidr Bray 1 for pH < 5.5 (kg Ph a-1)

1020304050+

614202834+

3024181510 (maintenance)

6.3 Potassium

As a guideline, the potassium content of soil is approximately 80 mg kg-1 for heavily textured, clayish and 60 mg kg-1 for lightly textured sandy soil. According to this guideline, potassium fertilisation will not often be needed. At lower analyses, potassium should be applied as for wheat. If the fertiliser is band placed, a too-high salt load could cause damage and it is recommended that potassium be broadcast and mixed into the soil.

Guidelines for potassium fertilisation according to soil analysis (citric acid or Bray 1, mg kg-1)

Heavily textured soils Lightly textured soils

Potassium (mg kg-1)K fertilisation

( kg ha-1 #)Potassium (mg kg-1) K-fertilisation (kg ha-1)

< 5050 – 80

> 80

3020

0 – 20

< 5050 – 80

> 80

30150

6.4 Sulphur

The sulphur requirement of canola is approximately four times that of wheat. Special attention therefore needs to be paid to the fertilisation programme in terms of sulphur. It is generally accepted that the sulphur requirement of canola is 15 to 20 kg S ha-1 per ton of grain yield per year. For sulphur supplementation in canola, the guidelines in the table below can be used. The time of sampling is important (shortly before planting), since the S content of soils often varies during the season. The carbon content provides a relatively good indication of the sulphur status of soils, with values < 1% indicating possible suboptimal levels.

22 CANOLA MANUAL

Guidelines for sulphur fertilisation according to sulphur content of soils

Sulphate S (mg kg-1 in soil)

Interpretation for fertilisation recommendation

< 6 Defi cient: S application higher than specifi c crop requirement (> 15-20 S ha-1)

7-12 Suffi cient: S application at maintenance level (15 kg S ha-1)

> 12 More than suffi cient: S application less than maintenance level (10 kg S ha-1)

Sulphur should preferably be applied in combination with nitrogen as topdressing during the growth season. The latter is particularly important on highly leached soils with a carbon content of < 1%. Alternatively, an application of 300 kg ha-1 gypsum (Ca2SO4) can be made – either on top or worked in shallowly – before sowing in soils with a history of defi cient sulphur content. This will be suffi cient in most cases. It is important to note that plants can only take up sulphur in the water-soluble form (SO4=).

6.5 Other plant nutrients

Canola is susceptible to boron and molybdenum defi ciencies, particularly if molybdenum defi ciencies are accompanied by a low pH. Defi ciencies can be counteracted by applying sodium molybdate (150 g ha-1 as foliar sprays) and solubor (1 kg ha-1 as foliar sprays). The practice of seed treatment with molybdenum is not recommended, since suffi cient molybdenum is usually not applied with this method. The use of boron as a soil application in the canola year is not recommended, since it can hamper the germination of the seeds. The copper, zinc and manganese requirements of canola are higher than those of wheat.

Soil analysis norms for trace elements that are currently used for canola (ppm or mg per kilogram, EDTA soluble)

Element Defi cient Low Suffi cient

Copper 0.3 0.3 – 0.5 0.5

Zinc pH < 5.5 pH > 5.5

< 0.5< 0.7

0.5 – 0.7 0.7 – 1.0

>0.7>1.0

Manganese pH < 5.5 pH > 5.5

< 5.0< 10.0

5 – 010 – 20

25

Boron (warm water) 0.2 – 0.3 0.3 – 0.5 0.5

Certain factors, such as soil texture, pH, liming, leaching, high carbon content and soil colour can often be used as an indication of possible defi ciencies. The larger fi gures are used in the case of soils with a higher potential..

CANOLA MANUAL 23

Leaf analysis norms for canola

N > 3.5% Suffi cientK > 2.2% Suffi cientP > 0.3-0.6% Suffi cientCa > 1.4-3.0% Suffi cientMg > 0.2-0.6% Suffi cientNa > 0.03-0.5% Suffi cientS > 0.5% Marginal > 0.5-0.8% Suffi cientCu > 3-5 mg kg-1 Suffi cientZn > 20 mg kg-1 Suffi cientMn > 30-200 mg kg-1 NormalB > 20-50 mg kg-1 NormalMo > 0.25-0.5 mg kg-1 Suffi cient

(Source: “Interpretation of Plant Analysis”, CSIRO Publishing, PO Box 1139, Collingwood, VIC 3066, Australia)Analyses should be evaluated in the context of vigour and possible spray residues

Supplementation of trace elements

Trace element supplementation is necessary when the soil is analysed as being “low” or “defi cient”. Defi ciencies of trace elements can be supplemented by foliar sprays or soil applications.

The residues of soil applications usually persist much longer than those of foliar sprays. In calcareous soils with a high pH, manganese in the soil becomes inaccessible to plants and it will have to be applied as a foliar spray.

Important aspects to be borne in mind for the successful supplementation of trace elements are:

Defi ciencies should be identifi ed correctly. Plants should be growing actively (not be under moisture stress) and the leaf area should be

suffi cient Plants should be dry and it should not be very hot during supplementation. At least 2 – 3 hours should pass after foliar spraying before there is rain or irrigation to ensure

suffi cient uptake by the plant. The specifi cations of the manufacturers should be followed thoroughly to ensure success

. Trace elements should not be mixed with herbicides. If mixtures of trace elements are used, the lower dose of the different elements should be used

in order to prevent a salt load that is too high, which can cause leaf scorch. Proper wetting of the plant is very important for the best results, i.e. use the recommended quantity

of water if possible.

24 CANOLA MANUAL

Trace element recommendations for canola

Trace elementsFoliar sprays500 litre water per hectare

Soil applicationkg per hectare

Zinc (Zn) 1 – 2 kg Zinc oxide 3.5 – 7 kg Zinc oxide

Manganese (Mn) 2 – 4 kg Manganese sulphate Ineffective

Boron (B) 2 – 4 kg Borax or 0.5 – 1.0 kg Solubor

Not recommended

Copper (Cu) 1 – 1.5 kg Copper oxychloride 2.5 – 5.0 kg Copper oxychloride (take care on sandy soils)

Molybdenum (Mo) 100 – 150 g Sodium molybdate orAmmonium molybdate

250 – 500 g Sodium molybdate orAmmonium molybdate

Plant populations of 50-80 plants m-2

CANOLA MANUAL 25

7. WEED CONTROL

7.1 General

Canola is at present the most important annual rotation crop that is available to offer producers an alternative in their struggle against the growing problem of herbicide resistance.

The aim in a well-planned anti-resistance strategy should be to control the grass weeds in the canola phase effectively and to make sure that the fi elds are free of broadleaved weeds in the cereal phase. If this strategy is carried out effectively, diffi cult broadleaved weeds such as wild radish and spiny emex will be limited to a minimum.

7.2 Control strategies and agents

Weed control should begin as early as during seedbed preparation by removing all the weeds that have already germinated, either mechanically or chemically, before sowing. Early cultivation after the fi rst rain stimulates the germination of weeds.

Herbicides for application before emergence of canola and weeds

ACTIVE INGREDIENT TRADE NAME HERBICIDE CLASSIFICATION

GROUP

REMARKS

Metazachlor Butisan S K3Annual grasses + some BLW*

Simazine[NB – only triazine-resistant cultivars]

Simazol SCSimanex 500 SC

C1Annual BLW + and certain

grasses

Terbutilazine + Simazine[NB – only triazine-resistant cultivars]

Tylsimex 500 SC C1Annual BLW + certain grasses

Trifl uralin Crew K1Annual grasses and certain

BLW

* BLW – [annual] broad-leaved weeds

26 CANOLA MANUAL

For the best results with pre-emergence herbicides, the following are important:

Time between last cultivation / planting / spraying of herbicide and follow-up rain to wash the herbicide into the soil should be as short as possible.

Rainfall during or shortly after application [10 – 15 mm for leaching in] of herbicide. Seedbed should be free of weeds, clods and plant residue from the previous season. Seedbed should be fi rm.

Herbicides for use after emergence of canola and before emergence of weeds

ACTIVE INGREDIENT TRADE NAME HERBICIDE

CLASSIFICATION GROUP REMARKS

Propyzamide Kerb K1 Annual grassesNB – to 3-leaf stage

Herbicides for use after emergence of canola and weeds

ACTIVE INGREDIENT TRADE NAMEHERBICIDE

CLASSIFICATION GROUP REMARKS

Imazamox[NB – only Clearfi eld

canola]

Cysure B Annual BLW and grasses

Clopyralid Lontrel O Annual BLW

Ethamet sulphuronmethyl

Lomex B Annual BLW

Haloxyfop-methyl Gallant Super A Annual grasses

Propaquizafop Agil A Annual grasses

Quizalofop-P-ethyl l Co-Pilot A Annual grasses

Quizalofop-P-tefuryl Pantera A Annual grasses

Tepraloxydim Aramo A Annual grasses

For good results the weeds should be growing actively. Note the size of the weeds that is specifi ed on the label. Post-emergence herbicides require good foliage wetting. Water volumes should therefore not be reduced, particularly with regard to a dense stand of weeds. Also take note of shielding of the herbicide by the crop plants if it is applied later, since it can cause ineffi cient wetting of the weeds.

Canola is very sensitive to broadleaf herbicides [particularly sulphonyl ureas], which are used for wheat, and the spray equipment should be cleaned thoroughly with chemical detergents beforehand. Avoid drifting of the herbicides in the direction of canola when adjacent fi elds are sprayed. Also take note of the withholding periods of the herbicide[s] that were used in the previous year on the fi elds designated for canola.

CANOLA MANUAL 27

8. DISEASES AND DISEASE CONTROL

8.1 Seedling dieback (Fusarium spp., Pythium spp., Rhizoctonia solani)

Pre- and post-emergence dieback of canola is caused by a complex of organisms. Typical symptoms of this disease are sudden wilting and seedlings that fall over or dry out. Dieback takes place as a result of rotting at the surface of the soil. The disease usually occurs in the fi rst 4 – 6 weeks after planting and seedlings that survive to the 3 – 4 leaf stage will usually continue growing. It is known that 80-100% infection of seedlings can occur and yield losses of up to 30% have been reported overseas.

The following practices can reduce losses as a result of seedling dieback: Avoid planting during cold, wet conditions, which hamper the germination of the seeds and seedling

growth, since these conditions promote disease infestations. The spreading of Pythium spp. is favoured particularly by wet conditions. In cases where plantings are eradicated by this disease, successful seedling establishment can be achieved by replanting, as long as the soil temperature and moisture conditions are favourable.

Plant the seed at the recommended planting depth. Seeds that are planted too deep give rise to delayed seedling emergence and the seedlings are therefore exposed to pathogens for a longer period of time.

Use seed of good quality. Seedlings from poor quality seed are more susceptible to seedling dieback.

Seed treatment. Treatment of seeds with fungicides protects the seedlings for the fi rst 6 weeks after planting.

An integrated control strategy that includes the abovementioned practices can make a large contribution to the successful control of this disease. Little is currently known about the effect of resistant cultivars and crop rotation on the incidence and development of seedling dieback.

8.2 Blackleg (Leptosphaeria spp. / Phoma lingam)

Blackleg is caused by two Leptosphaeria species, viz. Leptosphaeria maculans and Leptosphaeria biglobosa. Leptosphaeria maculans is more aggressive than Leptosphaeria biglobosa and both species consist of different strains. The asexual phase of the fungus is known as Phoma lingam. The fungus survives primarily in canola residue that is left on the fi elds at the end of the growth season. After enough rain has fallen at the start of the growth season, spores are released from the stubble and transported by wind to the young seedlings, where they attach to the cotyledons, leaves or hypocotyls and infect them. The fungus then spreads and causes characteristic greyish lesions (Phoma leaf lesions) with small black specks (fruiting bodies) that contain the asexual spores of the fungus. The fungus grows from the lesions through the petiole into the stem, where

28 CANOLA MANUAL

it causes stem and crown lesions later in the season. This phase is usually the most dangerous, since the upwards and downwards transportation of water and nutrients is disrupted. This gives rise to a decrease in seed formation. Losses worldwide are estimated at about 10%, although it could be much higher. When the stem is considerably weakened as a result of infection, the plant will lodge. Rain can also cause the spores to be splashed from leaf lesions to nearby plants and thereby cause secondary infections. Pod infections result in infected seeds..

The following management practices can be applied:

Plant resistant cultivars that are adapted to your environment.

Use a crop rotation system in which canola is only cultivated on the same soil once every 4 years

. Canola should be planted as far as possible from the fi elds on which it was cultivated in the previous year.

Use certifi ed seed, since the disease is seed borne.

The fungus’s host series is limited to the cabbage family (Cruciferaceae). Cruciferous weeds such as wild radish and wild mustard, which can act as alternative hosts for the pathogen, should therefore be controlled effectively.

Volunteer canola is also infected by the fungus and should therefore be depastured or removed as soon as possible. The re-growth of volunteer canola can then be controlled with a contact herbicide.

Canola residues can be removed at the end of the growth season by burning it, burying it (cultivation) or depasturing it. These practices do not fi t in with minimum or no tillage, however, and should only be used in exceptional cases.

The above practices can give rise to a reduction in losses as a result of blackleg. Attention should also be paid to the fact that the loss of resistance might have taken place earlier, and that it is particularly possible if the same cultivars are repeatedly exposed to high disease pressure. No chemical treatment of blackleg is currently registered in South Africa.

8.3 Stem rot (Sclerotinia sclerotiorum)

Sclerotinia sclerotiorum has a very wide range of hosts and attacks lupins among others. The symptoms appear during fl owering or thereafter. However, the fungus can also infect seedlings or young plants under favourable conditions. Warm, moist conditions promote the development of the disease. The sclerotia survival structures are the most important source of inoculum for the fungus and can survive in or on the soil for up to seven years. This means that crops that are attacked by this fungus should not follow each other in short rotation systems. The tendency to plant canola after lupins in order to utilise nitrogen left behind in the soil by the lupins can cause big problems.

Sclerotia are often formed in and on the pods, and contaminated seeds can transfer the disease. As a result, the recommendation is to use only certifi ed seeds..

CANOLA MANUAL 29

The most characteristic symptoms of the disease occur at the bottom of the stems of plants and later also on the pods. In the case of canola, light bleached spots with a slightly grey middle portion can be seen on the stems – usually at the point of attachment of the leaves or lateral branches. The fungus does not form spores on the affected plants, but a dense bundle of white hyphae, in which sclerotia can often be seen, are formed under favourable conditions. These sclerotia fall on the ground, where they later germinate and then form spores that infect the plants initially. No further spore formation takes place on the infected plants. Hyphae that grow on the soil can infect other plants, however. This is why the disease characteristically occurs in spots. Later cultivation spreads the sclerotia. Affected plants usually ripen prematurely and die back. This causes a lower yield and seed weight.

Besides for crop rotation and the use of certifi ed seed, attention should also be paid to weed control in the management of stem rot. Large weed populations increase the moistness between plants, which means conditions are more favourable for the development of disease. It is also important to note that the cultivars that currently are used do not have resistance to stem rot..

Left: Sclerotinia stem rot on canola

Above: Black leg lesion on canola seed leaf

9. INSECT PESTS AND CONTROL

9.1 Insect pestsRedlegged earth mite /black earth mite (Halotydeus destructor) and Blue oat mite (Penthaleus major)

April/May/June

Adult insects of both species feed on young seedlings and cause characteristic silver/white fl ecks and malformation of the cotyledons and young leaves. Heavy infestations can cause considerable damage to crops in a few days.

Regular inspections for damage and the activities of mites during the fi rst 3 to 5 weeks after emergence are important, particularly if environmental temperatures are high. Seed treatment with dimethoate just before planting provides a degree of protection, but usually requires follow-up sprays when they emerge and about two to three weeks thereafter.

Redlegged earth mite is the most serious pest of canola seedlings. Heavy infestations will thin the stand, delay growth and eventually impair yield. However, rapidly growing canola seedlings and more mature canola plants can handle a reasonable degree of infestation.

Cabbage aphid (Brevicoryne brassicae)

April to October

Although other aphid species can also attack canola, the cabbage aphid is currently the primary species that feeds on canola. Aphids migrate from host weeds around canola fi elds and the populations can accumulate very rapidly if the weather is warm. Cold weather delays the accumulation of populations and they can even become smaller if it rains well. Canola is extremely susceptible to aphid contamination during the early growing stages. Heavy and longstanding contamination during the fl owering and podding stages can also prevent fl ower formation and seriously impair the set and fi lling of pods. Oil quality and seed vigour can also be infl uenced. It is particularly important to protect canola from aphids under conditions of moisture stress.

Regular monitoring of aphid infestation levels is important. Look carefully between the young leaves at the growth tip during the rosette phase, since even very low aphid infestations can inhibit the growth of the canola plant during this stage. Mature canola has a higher tolerance to aphids. When a decision needs to

Bird damage on canola pods

32 CANOLA MANUAL

be taken whether or not to spray, it is important to determine the number of infested plants rather than the quantity of aphids.

Lucerne fl ea (Sminthurus viridis)

April/May/June

Lucerne fl eas are small, wingless insects that can jump relatively long distances if they are disturbed. The eggs that are transferred from the previous season hatch during the autumn months. Heavy infestations of lucerne fl eas are common after a legume-pasture phase.

The insects eat small round holes in the cotyledons and young leaves. Heavy infestations can delay seedling growth and even cause young plants to die. Regular monitoring of cotyledons and young leaves is important.

Diamond-back moth (Plutella xylostella)

July - September

Depending on the environmental temperature, the adult insect (small moth with diamond pattern on closed wings) is usually noticed by the end of the stem elongation phase. Under hot weather conditions the infestation can occur as early as in the rosette phase. The light green larvae, which often hang from a silk thread, eat holes in the leaves. Pods are also attacked, but the damage is usually superfi cial and the pods are seldom drilled through. However, the damaged pods tend to dehisce more easily..

Cotton bollworm (Helicoverpa armigera.)

August – September

Larvae differ in colour, varying from light green to dark brown, with corrugated skin and small, short black hairs. Heavy cotton bollworm infestation is usually associated with heavy aphid contamination, since the moths feed on the honeydew that is secreted by the aphids. Small larvae seldom cause serious damage to the pods, since they only feed on the surface of leaves and pods. Larger larvae (longer than 1 cm) bore into the pods and cause yield losses. Crops should be monitored from the fl owering stage. Look for damage to the pods rather than only at the number of larvae that are present.

9.2 Snails and isopods

Canola is known to be particularly vulnerable to attacks by snails. Although various types of snails can cause damage, the most damage is caused by the slug species Deroceras reticulatum, Deroceras panormitanum and Milax gagates.

CANOLA MANUAL 33

The largest damage is caused just under the soil surface to the seeds and seedlings just after planting by snails and isopods (Porcellio laevis), when the snails eat the seed embryo or eat through the small stem of the seedling. The result is that the seed does not germinate, or that the seedling dies shortly after emergence. This can have immense economic consequences, as the eaten spots need to be replanted and treated with chemicals to maintain the yield and prevent the colonisation of open fi eld by weeds. Snails can cause immense damage because they are voracious eaters and manage to eat plant material amounting to 30 to 50% of their body mass in one night.

Snails are also polyphagous, which means that although they prefer soft, green material (seedlings), they also eat stubble and all types of animal and plant residues that are present in the soil. Snails are hermaphrodites and have the ability to procreate on their own, at which time they lay between 100 and 550 eggs, depending on the specie. Snails are long-lived (they live 9 to 18 months) and can adapt their biological activity to wait for more favourable weather and environmental conditions. Lastly, 85 to 90% of the snail’s body consists of water, which is favourable for the transfer of various viruses, bacteria and fungi to plants through their slime.

The activities of snails are infl uenced by environmental factors such as wind, air temperature, soil surface temperature, humidity and soil moisture content. Heavy rainfall during the summer and autumn increases the risk for damage by snails. Production factors such as the increasing use of conservation farming practices (minimum or no tillage); fallow fi elds; crop rotation where a crop favourable to snails precedes a highly susceptible follow-up crop (e.g. canola before wheat); lower snail resistance in new canola cultivars; reduced glucosinolate content and invasion by new snail species may all contribute to increased damage by snails.

Although the degree of contamination therefore differs between seasons, it is increased by the presence of crop residues that cover the soil. In this way, drying out is delayed and soil temperatures are lower. Natural veld, uncultivated fallow fi elds and soil strips surrounded by wire fences can also serve as a source of contamination. Control measures should therefore also be implemented in these areas.

The isopods that occur naturally in the canola-producing regions of the Western Cape fulfi l an important role in conservation farming systems in that they promote the degradation and recirculation of harvest residues. According to investigations, isopods are more common in pastures than in canola fi elds and their numbers are further reduced by soil disturbance during the planting process. Damage is caused when the isopods that are attracted to the surface of the soil after the fi rst autumn rains eat some of the young, juicy canola in an effort to avoid dehydration in subsequent hot and dry periods. The canola stems are damaged or eaten off in this manner, with the result that the seedlings lodge. Because the crop has an apical growth habit, it cannot re-sprout and therefore dies. If infestations are heavy, canola fi elds can literally disappear overnight. Isopods can also feed underground on the germinating canola seeds, with the result that the seedlings do not even emerge. Because of the unpredictability of rainfall in this region, and because of the reduction in yield potential if planting takes place late, postponing planting to prevent damage is not a solution to this problem.

Carbaryl-containing snail bait will result in 100% control the isopods eating it. The endeavour of current research is to fi nd a technique to protect the seed and young seedlings for the fi rst three weeks after planting

34 CANOLA MANUAL

by means of a chemical seed treatment. If it should be successful, only the isopods that are in direct contact with the seed or seedling will be controlled.

9.3 Control measures

Before planting

The post-emergence spraying of insect pests that feed on the underground parts of germinating seedlings, e.g. false wireworm, black maize beetle and to a certain extent cutworms or those that shelter under straw, stones or clods, e.g. isopods, millipedes and earth beetles, is generally unsuccessful. If these pests occur on the farm/fi elds historically, the only possible solution is to apply chlorpyrifos, before planting, through broadcast application of at least 1.0 L ha-1 and incorporation into the soil.

Producers who experience serious problems with snails have found that scattering snail bait before planting contributes to a reduction in the population as long as no alternative source of food is available. Slugs in particular, which live in the soil, are attracted at night. Problems with snails are usually experienced on cool, southern slopes and particularly in stony areas. Continuous weed control during the post-harvest period and before planting appears to have a negative effect on snail populations. Snails penetrate the fi eld primarily from the outside in, and it can be benefi cial to treat the area adjacent to the fi elds and keep it clean.

At planting

Seed treatment with dimethoate provides a degree of protection against redlegged earth mite, lucerne fl ea and aphids that feed on the cotyledons and young leaves of germinating plants. Research is at present under way to register other insecticides as seed treatments. Under favourable conditions, especially if environmental temperatures are high, heavy infestations, particularly in young crops, can cause considerable damage within a few days. Regular inspections from germination onwards therefore are essential. If the characteristic silver/white fl ecks and misshapen cotyledons and leaves are noticed, a follow-up spray should be applied.

Rapidly growing canola seedlings and more mature plants are more resistant and can endure higher infestation levels. If snail bait that was applied before planting dissociates and becomes inactive, a second application of snail bait should be considered as soon as snail activity is noticed again. Early post-emergence

Monitor on a regular basis for any signs of insect damage. If damage is noticed, the causative insect should be identifi ed, since the various pests may require different treatments.

If redlegged earth mite, lucerne fl ea or aphid damage is noticed, a suitable pesticide should be sprayed against the specifi c insects. If snails [slugs, conical snails or dune snails] are responsible for the damage, a further application of snail bait should be considered. If cutworms are identifi ed, a corrective spray, for example with pyrethroids, could possibly solve the problem.

CANOLA MANUAL 35

As soon as the plants have reached the 3- to 4-leaf stage and are growing actively, the chances are good that they will outgrow the insects of the seedling phase.

Vegetative to rosette phase

Aphids are the most common pest feeding on canola during this period, with cabbage aphid being the primary specie. Aphids migrate from host weeds around crop fi elds and populations can increase rapidly if weather conditions are warm. Cold weather delays the accumulation of populations. Aphid populations can even reduce under cold conditions accompanied by rain.

During the early growth stages, canola is extremely susceptible to aphid damage. Regular monitoring of infestation levels is important. Note should be taken of aphids between the young leaves at the growth tip, particularly during the rosette phase, since even a few aphids during this stage can impair the growth of the canola plant. If a decision has to be taken on whether or not to spray, it is advisable to determine the number of infested plants rather than the number of aphids per plant and to use this as the norm for infestation. It is particularly important to protect canola against aphids during conditions of moisture stress.

Flowering and podding stages

In addition to aphids that can cause stress in the plants all the time, diamond-back moth larvae and Canadian bollworms are the insects that cause the most damage.

Canadian bollworm eggs are laid singly on the upper surface of the leaves, primarily from the fl owering stage. The night-fl ying moth, with reddish brown to light brown front wings and creamy white back wings, can lay as many as 1000 eggs during her lifespan of 5 to 8 days. The white eggs become darker and hatch after ± 6 days. After hatching, the small larva [shorter than 1 mm] moults six times within 14 – 18 days to grow into an adult larva of approximately 3 cm, after which it falls to the ground to pupate. The pupa stage lasts ±20 days, after which the moth appears to start the following life cycle.

Because of the excessive and prolonged use of pyrethroids for the control of Canadian bollworm, some populations are more resistant to them and it therefore is not controlled effectively. If there is a history of poorer results with pyrethroids in the region, insecticides from another chemical group [e.g. methomyl] should rather be considered.

9.4 Important warning with regard to bees

Canola fl owers are a preferred food source for bees. Bees travel up to 5 km to fi nd canola fi elds for feeding

Producers should please note that, when canola is fl owering and sprays against insect pests are considered, the choice of insecticide and time of application should be made so that it has the least possible impact on the bees.

36 CANOLA MANUAL

Chemical agent

Insect pest Contact effect as a result of direct spray contact with wet residue (< 1 hr after spraying)

Contact effect of dry residue (1 – 24 hrs after spraying)

Residual effect (> 4 hrs)

Remarks

Alpha-cypermethrin

Diamond-back moth/Bollworm

High Low Low Ground application: Do not apply to fl owering crop while bees are active or within 1 hr before expected bee activity. Aerial application: Do not apply to fl owering crop or any other crop adjacent to fl owering crop while bees are active or within 1 hr before expected bee activity..

Beta-cyfl uthrin Diamond-back moth/Bollworm

High Low Low Ground application: Do not apply to fl owering crop while bees are active or within 1 hr before expected bee activity. Aerial application: Do not apply to fl owering crop or any other crop adjacent to fl owering crop while bees are active or within 1 hr before expected bee activity.

Chlorpyrifos Aphids/Diamond-back moth

High High High Ground application: Do not apply to fl owering crop. Aerial application: Do not apply to fl owering crop. Do not apply to any crop adjacent to fl owering crop while bees are active or within 1 hr before bee activity.

Cypermethrin Diamond-back moth/Bollworm

High Low Low Ground application: Do not apply to fl owering crop while bees are active or within 1 hr before expected bee activity. Aerial application: Do not apply to fl owering crop or any other crop adjacent to fl owering crop while bees are active or within 1 hr before expected bee activity..

Demeton-S-methyl

Aphids High Medium Low Ground application: Do not apply to fl owering crop. Aerial application: Do not apply to fl owering crop. Do not apply to any crop adjacent to fl owering crop while bees are active or within 1 hr before bee activity..

Threat to bees of insecticides used in fi eld crops

CANOLA MANUAL 37

Chemical agent


Contact effect of dry residue (1 – 24 hrs after spraying)


Remarks

Dimethoate Aphids High Medium Low Ground application: Do not apply to fl owering crop. Aerial application: Do not apply to fl owering crop. Do not apply to any crop adjacent to fl owering crop while bees are active or within 1 hr before bee activity.

Gamma-cyhalothrin



Lambda-cyhalothrin



Methamidofos Aphids/Diamond-back moth

High High High Ground application: Do not apply to fl owering crop. Aerial application: Do not apply to fl owering crop. Do not apply to any crop adjacent to fl owering crop while bees are active or within 1 hr before bee activity.

Methomil Aphids/Diamond-back moth/Bollworm


38 CANOLA MANUAL

Chemical agent


Kontak effek met droë residu (1-24u na bespuiting)


Remarks

Omethoate Aphids High Medium Low Ground application: Do not apply to fl owering crop. Aerial application: Do not apply to fl owering crop. Do not apply to any crop adjacent to fl owering crop while bees are active or within 1 hr before bee activity.

Oxydemeton-methyl

Aphids High Medium Low Ground application: Do not apply to fl owering crop. Aerial application: Do not apply to fl owering crop. Do not apply to any crop adjacent to fl owering crop while bees are active or within 1 hr before bee activity..

Pirimicarb Aphids Low Low Low Do not apply to fl owering crop during high bee activity..

Tau-fl uvalinate Aphid/Bollworm

Low Low Low Do not apply to fl owering crop during high bee activity..

Insecticides and fungicides for seed treatment

Seed treatment

Not applicable Not applicable Not applicable

Not applicable.

Snail baits (various)

Snail control Not applicable Not applicable Not applicable

Not applicable

Fungicides Disease control

Low Low Low Do not apply to fl owering crop during high bee activity..

Herbicides Weed control

Not applicable Not applicable Not applicable

Apply herbicides before crop is in fl ower..

10. HARVESTING CANOLA

10.1 Harvest techniques

Canola can be harvested directly or fi rst swathed and then threshed. Direct harvesting and swathing each have their own advantages and disadvantages that should be considered thoroughly before harvest time. This, together with the availability of equipment, should help to determine the fi nal decision made by the producer.

The advantages of swathing are as follows:

More uniform ripening, especially in uneven stands and where soil types differ. Faster and more uniform drying of plants reduces problems with moisture. Easier and earlier harvesting of the crop. Reduced seed losses during ripening and harvesting of the crop.

According to Australian and Canadian literature, defoliants can be used as a replacement for swathing. Care should be taken, however, as the action of the defoliants is rapid and the risk of seed losses due to shattering is larger than in a crop that is permitted to dry out normally. Since such applications have to take place by way of aerial spraying, adjacent fi elds can easily become damaged. If they are swathed, the cutting height should be above the branching of the plants so that a fork is formed in which the wind row can lie so that it is not blown by the wind or sink too deeply into the stubble. Better air fl ow is ensured and the quantity of material that has to be handled by the swather and combine harvester is less. Cutting should preferably take place with the normally prevailing wind direction and it also should be picked up from the side where the pods lie.

Success can also be achieved with direct harvesting. Careful and timely monitoring of the stand for ripeness during the harvesting process is of cardinal importance. If drying facilities are available, harvesting can begin at 14% moisture. However, canola can only be stored with a moisture content of lower than 8%.

10.2 Time of harvest

Canola is ready for harvesting as soon as the pods start yellowing, the seeds become darker in colour and if there is a rustling in the pods if they are shaken. As soon as the canola plant becomes mature, it usually ripens quickly and the optimum harvest period can be as short as a few days. Ripening begins at the base of the stalk and moves upwards. Do not wait until the plants are killed by frost before the harvesting process starts, since this could lead to larger seed losses and even have a negative infl uence on the oil content. Therefore ignore the green pods that might be found at the top ends of some plants.

40 CANOLA MANUAL

Canola is usually ready for swathing at about 14 to 28 days after fl owering is complete (fewer than 10% of the fl owers are still visible). Swathing should take place when 40 – 60% of the seeds have changed colour. Suffi cient pods in the middle of the main stem of the plant should be sampled at different places in a fi eld to draw the correct conclusions.

The seeds should be fi rm when they are rolled between the fi ngers and they should also have a moisture content of between 30 and 35% (35% is optimal). Some of the cultivars do not have a defi nite main stem and it is recommended that the pods at the middle of the highest pod-bearing lateral branches are sampled. Swathing too early can lead to losses in terms of yield, oil percentage, protein content and the quality of the oil. The swathed canola can be harvested when the moisture content of the seeds drops below 8% (7 – 10 days). If drying facilities are available, it can be harvested at an even higher moisture percentage.

10.3 Harvest losses

Harvest losses can be the result of pods that dehisce before and/or during the harvesting processes, but also as a result of seeds that “leak” from the combine harvester and the grain tanks. Canola seeds are very small and can easily “fl ow” through any opening in the combine harvester or grain tank. Grain tanks and combine harvesters should always be checked carefully for possible leakages and then be sealed.

The dehiscence of pods is determined by their moisture content, as well as by the temperature and humidity of the air. Pods will therefore tend to dehisce more in the dry, hot part of the day. For this reason, canola should preferably be harvested on cool days or during the cooler times of the day.

Other practices, such as a vertical cutting blade on the one side of the combine harvester to cut entangled pods, as well as extended threshing tables, have also been used successfully. It is benefi cial to move the pick-up reel of the combine harvester slightly to the back so that the pods can be fed in once they have moved across the threshing table. For the best results the pick-up reel should be rotated at forward speed. The correct adjustments to the combine harvester are extremely important. The combine harvester should therefore only be used according to the specifi cations given for rapeseed in the applicable manual.

If canola is picked up after it has been swathed, the picker should be set as horizontally as possible so that the wind row is disturbed as little as possible. The speed of the picker should be slower than in the case of winter cereals, otherwise the material will be sucked into the main auger, with associated seed losses. If possible, the speed of the picker should be the same as the forward speed of the combine harvester. The mat above the picker should also be placed higher, since the canola wind row has a greater volume than winter cereal wind rows.

According to the Australian literature, losses of 20 – 30 kg ha-1, that is to say < 5% of the yield, are acceptable.

CANOLA MANUAL 41

Sclerotinia lesions on canola stems

Canola fi eld in full bloom

11. UTILISATION OF CANOLA11.1 Human nutritionCanola seed contains approximately 36 to 46% high-quality vegetable oil and 20 to 24% protein. Canola oil is known worldwide for its good health properties and is used increasingly as cooking oil and in the production of margarine. Canola contains very low levels of saturated fatty acids and relatively high levels of oleic acid and linolenic acid. Of all the vegetable oils that have been used for human consumption, canola oil has the highest percentage of omega 3-fatty acids, which have been scientifi cally proven to reduce LDL cholesterol levels.

11.2 Animal feedBoth full-fat canola (the unprocessed seed) and canola oilcake (the residue after the oil has been pressed mechanically from the seed) are high-quality products that are utilised very well by farm animals.

The protein content of locally produced full-fat canola is approximately 24%, with an oil content of 36%. The canola oilcake that is available in South Africa has a protein content of about 36%, with an oil content of less than 1.0%. The so-called percentage of bypass protein of canola oilcake is approximately 28% and is comparable to the value of soybean oilcake.

The relative monetary value of full-fat canola as animal feed in contrast to soybean oilcake (47% protein) varies from 58% for dairy cattle and 94% for poultry to 100% for pigs. Canola oilcake, in contrast, varies from 53% for poultry and 60% for dairy cattle to 65% for pigs.

Studies undertaken at Elsenburg and at the University of Pretoria indicate that the optimum inclusion rate of full-fat canola is approximately 12% in the complete diets of lambs and 6% in the complete diets of dairy cows. Canola oilcake can be used at 15% in the complete diets of sheep and at 12% in the complete diets of dairy cattle.

Regarding monogastric animals, the ideal inclusion levels of full-fat canola and canola oilcake in the diets of pigs is 12 – 18%. For ostriches it is approximately 10% and for chickens the maximum inclusion levels appear to be between 5 and 10%. With the inclusion of full-fat canola in the diets of chickens, pigs and dairy cows, a healthier fat and milk fat profi le is obtained because it contains a higher concentration of unsaturated fats than saturated fats.

For the best utilisation of full-fat canola, the canola seeds should be mixed with the grain during the milling process. According to local research results, canola stubble fi elds can provide sheep with better grazing than wheat stubble fi elds. The canola residue is utilised well by the grazing animals and, with the correct supplementary feeding, grazing densities of more than two ewes per hectare can be maintained for more than three months.

11.3 BiofuelBecause of rising prices of mineral oils and concern about environmental pollution, there is increasing interest in the use of canola oil as a source of bio-diesel. According to European information, approximately 1050 kg of canola oil is required to produce 1000 kg bio-diesel and 100 kg glycerine. Although canola oil is used for the manufacture of bio-diesel on a commercial scale in a number of European countries, the profi tability thereof in South Africa is still being investigated.

Canola in crop rotation with legume pastures

44 CANOLA MANUAL

ACKNOWLEDGEMENTS

Contributions to the publication from the following are acknowledged with gratitude:

Mr Chris Cumming Bayer Crop Science

Dr Mark Hardy Department of Agriculture, Western Cape

Dr Tertius Brand Department of Agriculture, Western Cape

Dr Sandra Lamprecht ARC Research Institute for Plant Protection

Dr Geoff Tribe ARC Research Institute for Plant Protection

Prof GA Agenbag Stellenbosch University

Mr Piet Lombard and

the Cultivar evaluation

team of the Department of Agriculture, Western Cape

The compilers of the pamphlet “Canolaverbouing in die Wes- en Suid-Kaap”

The compilers of the pamphlet “Bemestingsriglyne vir canola in die Wintereënstreek”

The compilation of these production guidelines was made possible through the fi nancial support of the Protein Research Foundation (PRF) and THRIP. The PRF strives to make a real contribution to the promotion of the local production of vegetable oil and protein on a competitive basis in order to satisfy the growing protein requirements, and that will lead to an increase in the living standards of all people in South Africa.

The PRF trusts that the information contained in these production guidelines will help to stimulate canola production in South Africa – to the benefi t of all role players who are involved in the canola industry and also in related industries.

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