QI93027

South-West Queensland gardening guide

Information Series QI93027

South-West Queensland gardening guide Edited and Compiled by Julie Gordon, Peter Johnston and Chris Evenson Agricultural Production Group Charleville, West Region

Department of Primary Industries Queensland

ISSN 0727-6273 Agdex 280\20 Funded by the National Landcare Program © Queensland Government 1993 Charleville Pastoral Laboratory

Department of Primary Industries Department of Primary Industries GPO Box 46 PO Box 282 Brisbane Q 4001 Charleville Q 4470 Acknowledgements This booklet is a collection of notes and articles commonly used in handling most garden enquiries in South-West Queensland. Many of the articles were written by previous staff of the Charleville Pastoral Laboratory. These include Flora Smith and Peter Bowly. The assistance of Michelle Cook and Julie Capewell for typing is also gratefully acknowledged. Many thanks also to Jimmy Deignan for the artwork on the cover.

CONTENTS Page Gardening with bore water 1 Recommended pH ranges 6 Australian native plants for growing in 8 salt contaminated soil or with salt contaminated water Small herbacious species, (annuals 9 and perennials) for alkaline and/or salty soils Exotic trees, shrubs and creepers for 10 alkaline and/or salty soils Australian native plants for hot, dry 11 areas with limited water Growing better lawns 12 (i) The Water 12 (ii) Gypsum and Sulphur 12 (iii) Organic Matter 13 (iv) Watering 13 (v) Fertilisers 13 (vi) Lawn Grubs 13 Caring for your citrus trees in the South-West Queensland 14 Common pests and diseases of horticultural 15 crops in western Queensland Citrus and other fruits 17 (i) Queensland Fruit Fly 17 (ii) Red Scale 17 (iii) White Wax Scale 18 (iv) Citrus Aphid 18 (v) Citrus Gall Wasp 18 (vi) Spined Citrus Bug 19

Lawns 20 (i) Lawn Grubs 20 (ii) Felted Grass Coccid 20 (iii) Ants 20 (iv) White Grubs 21 (v) Broad Leafed Weeds 21 Trees and shrubs 22 (i) White Cedar Moth 22 (ii) Wood Borers 22 (iii) White Scale Insects 22 (iv) Powdery Mildew 22 (v) Grasshoppers and Locusts 23 Vegetables 24 (i) Curcurbits - Insect Pests 24 (a) Pumpkin Beetle 24 (b) Leaf-eating Ladybirds 24 (ii) Curcurbits - Fungal Diseases 25 (a) Powdery Mildew of Cucumber and Rockmelon 25 (b) Powdery Mildew of Marrow and Pumpkin 25 (c) Downy Mildew of Cucumber and Rockmelon 25 (iii) Aphids 25 (iv) Caterpillars 25 White Cabbage Butterfly (Cabbage grubs) 26 (v) Nematodes (eelworms) 26 Roses and other flowers 27 (i) Dieback in Roses 27 (ii) Caterpillars and other Leaf and Bud Eating Pests 27 (iii) Powdery Mildew 27 (iv) Two Spotted Mites 27 Which pesticides to buy? 28 The easy guide to chemicals 30 Your notes 32 FIGURES Soil pH 5

TABLES The easy guide to chemicals 30

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Gardening With Bore Water The first thing to remember when using bore water is that it will change the structure of the soil. This is because bore water is high in salts and extremely alkaline. The main soil types found in gardens in South-West Queensland are the sandy soils, sandy loams and the clays. The sandy soils are usually well drained and of a light free texture. This particular soil is very easy to manage when using bore water because the salts of the bore water are so readily leached out. The only physical problem encountered is the low water holding capacity. This is easily rectified with the addition of organic matter like leaf mould or compost. Sandy soils are generally acidic but like all soils the pH is governed by the type of water being used. In this soil it is relatively easy to control any excess alkalinity by the addition of Sulphur. In the Charleville, Eulo and Bollon areas, mulga soil is very common. This sandy-loam is a naturally very acidic and infertile soil. With good quality dam or river water, the addition of the appropriate fertilisers, and organic matter it can become quite a useful horticultural soil. However, with the use of bore water, it soon becomes alkaline and the surface can set as hard as cement and become impervious to water. This is caused by a chemical reaction between the salts in the bore water and the salts in the soil. Therefore the combination of mulga soil and bore water needs special cultural practices and careful selection of plant species. The common soil types in the Blackall, Cunnamulla and Augathella areas are the clay soils which are fairly fertile and usually alkaline. When bore water is added to these soils they quickly become very alkaline. They, like the mulga soils, set very hard which impedes the infiltration of water. When rain falls, the drainage is seldom good enough to allow leaching of the salts which are present in the soil due to the use of bore water. Therefore clay soils are possibly the most difficult soils to manage. The pH of the soils is a measure of its acidity or alkalinity. The pH is divided into 14 points, with 7 being the neutral point. Below 7 the soil becomes increasingly acid and above 7 increasingly alkaline. The relative acidity or alkalinity increases tenfold with each point ie. pH of 8 is 10 times more alkaline than the pH of 7 and a pH of 9 is 100 times more alkaline than 7. The pH of the soil has a strong influence on the nutrient availability. The best range is between 6.5 and 7.5. As you go further up or down the scale certain nutrients become unavailable (Figure 1).

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At the neutral pH level all nutrients are available. As the soil increases in alkalinity nutrients like nitrogen, iron, copper and others become unavailable, while at the other end of the scale, the acid end, other nutrients taper off. Therefore, the closer your soil is to neutral the more nutrients are available and the better your plants will grow. Plants respond differently to pH. The majority of species grow well between 6.5 and 7.5, that is, in the neutral range. Some are quite adaptable and will tolerate a pH from 6 to 8. Bulbs like Daffodils and Jonquils are in this category. However, some have a very special requirement and a narrow range eg. Azaleas require pH of 4.5 to 5.5, that is very acid, making them quite unsuitable for the alkaline conditions produced by bore water. When the pH is greater than 8.5, which is common with bore water usage, the range of species able to be grown is very restricted. The salts in the bore water cause a build up of salts in the soil which causes changes in the soil structure. This leads to hard setting of the soil and impermeability to water mentioned earlier. When the concentration of salts in the soil is too high the plants can actually perish for want of water. This happens because the membranes which convey water from the soil through to the plants are adapted to a certain solution strength of salt. When there is too much salt the water cannot pass through the membrane resulting in the plants death. Some plants are better adapted than others to salty conditions. These are mentioned in the list of salt tolerant plants included in this booklet. Those which occur on both salt tolerant and alkaline tolerant lists will be the most valuable plants for use when gardening with bore water. With problem water it is easier to use plants which are tolerant to salt and alkalinity problems rather than struggle with less suitable plants and have to use rather expensive chemical methods or time consuming mechanical measures. There are also a number of species, particularly native shrubs and trees, which after the establishment phase require little water (see the list of plants requiring minimum water). Some of these are quite attractive and are certainly worth consideration. It is usually best to choose plants which are adaptable to their surroundings rather than try to drastically change the environment. In small, special purpose areas, there are some steps which can be taken to grow less adapted plants. A necessary addition to most gardens are vegetables. Where there is a real problem with clay soils and bore water, it is often beneficial to form raised beds of well drained sandy soils on top of the heavy clay soil. This improves the drainage and keeps the salt content to a minimum. Do not mix the sandy soil into the clay. A bed 20 to 30 cm high is adequate for annual vegetables and flowers and some ornamental trees and shrubs. Some fruit trees such as stonefruit (peaches, nectarines, apricots and plums) require 30 to 40 cm of sandy soil while others such as citrus and grapes require 50 cm or more.

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The sandy soil should be kept in place with logs, rocks etc. Beds should be large enough to accommodate the root system of the plant being grown, for example 4 m wide for a mature citrus tree. These beds dry out quickly. Trees should be planted in rows for ease of formation of beds. The soil structure can be improved by the addition of organic matter and the soil pH acidified by the use of Sulphur and Nitrogen in the form of Sulphate of Ammonia. Beds for annual flowers may be treated in the same way as the raised bed for the vegetable, and of course there are some annuals which are more suitable than others. These are included in the lists. Lawns can be maintained in reasonable condition, with the use of Gypsum to improve the soil structure, and Sulphate of Ammonia as the nitrogen fertiliser. When the water is of very poor quality and the soil heavy, it is sometimes best to restrict the area of lawn to special purpose areas, such as near a barbeque or in a narrow strip close to your vegetable patch. It's surprising how attractive a garden can be with only a small lawn area and large areas of shrubs and trees, which can be kept tidy with heavy mulches of leaves and manures. A more detailed section on lawn care is in this booklet. As a general rule for trees and shrubs it is best to concentrate on the ones which are suited to the environment by being adapted to alkaline and salty soils or by having an annual water requirement which is similar to the average rainfall. If you wish to have fruit bearing trees in your garden it may be helpful to have at least a couple of citrus trees, perhaps a lemon and an orange, or grapes. Raised beds are again the answer in clay soils, because of the drainage aspect which is an important factor when considering citrus. Some chemical manipulation can be carried out to advantage. Some other fruits such as dates are well suited to salty conditions in the lighter soils and some nut trees like almonds are fairly tolerant of alkaline conditions. If desired plants are not suited to local soil conditions chemical treatment of the soil may be necessary. This sort of treatment is rather expensive for large scale use and if not used correctly can be dangerous. In sandy soils chemicals such as Sulphur and Sulphate of Ammonia can be used very effectively to reduce the pH to an acceptable level. Water moves freely through this type of soil and even bore water helps to keep the salts moving. With care and common sense a sandy soil can remain productive almost indefinitely. Clay soils are rather a different proposition. The addition of Calcium Sulphate in the form of Gypsum to clay soils can be very beneficial. It improves the soil structure and the calcium is a necessary plant nutrient. Sulphur can also be very helpful to reduce pH. Wettable Sulphur is the best form to use because its soluble characteristics make it more readily available to the plants. Sulphur is the cheapest form of acid available at the moment.

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When adding nitrogen fertiliser always use Sulphate of Ammonia, because it has a more acidifying effect than Urea. A problem with the use of excess chemical fertilisers in clay soils is with the lack of drainage. It will increase the salts in the soil. The salts from the fertiliser together with the bore water salts will reduce the ability of the plant to extract the water from the soil, as previously discussed. So where there is a high content of salt in the soil it sometimes does more harm than good to add a lot of chemicals. When trying chemical treatment, start with a small amount, and be very careful. It may be better to supply nutrients as manure under theses conditions. Organic matter is a very important component of any soil as it helps hold moisture in sandy soil, improves the structure and drainage of clay soil, helps in chemical reactions and makes available plant nutrients. Leaf mould and animal manures are a good source of organic matter. These are more suitable for use if they have been composted first. Using fresh leaf mould and animal manure can be dangerous because the breaking down effect by microscopic bugs can cause severe nitrogen deficiency. Also if the organic matter is composted it will change the nutrients into a form which are most suitable and available to the plants. Most gardening books and manuals have good sections on the preparation of compost heaps. When using mulches or organic matter do not have the mulch right up to the trunks of the trees and shrubs as this will cause problems like collar rot to develop. Always stop the mulch at least 15 cm from the trunk. When collecting animal manure avoid areas where chemicals such as sheep or cattle dip or jetting fluids have been used. Some of the preparations can be toxic to plants and can cause a lot of problems in the garden. The application of bore water is a very critical point of the gardening. Probably the best advice is to use as little as possible. Where practical use those plants with a low water requirement or which are adaptable to salty or alkaline conditions. Where other species are required reduce the amount of water needed as much as possible by the use of mulches to reduce the amount of evaporation loss, which in this climate can be enormous. Where there is a need for large amounts of water, it is best supplied at less frequent intervals as it helps to wash the salts down away from the feeder roots. Sprinkling for only a few minutes every day only helps to concentrate the salts in the root zone. A good flood once a week is better than a little each day. Where a drip system is already in use, it is usually better to increase the rate of flow, let the plants have a good water, then turn it off and repeat it in a weeks time.

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With salty water, it is best to apply water to the ground rather than the foliage. Where spray application is necessary, such as lawns, it is better to water at night to minimise the salt burn on the leaves due to evaporation. In sandy soil, the occasional very heavy watering to leach out salts is beneficial. Lastly, very special purpose plants can be grown in pots using rain water. Useful plants such as strawberries, herbs and egg tomatoes all make quite attractive potted plants. A cumquat tree in a large tub will provide a lot of fruit for marmalade. Indoor and patio plants are a most attractive addition to any home. Fig 1. Soil pH ranges and its effects on plant nutrient availability. (a thicker line indicates greater availability of the nutrient). SOIL pH Acidic Neutral Alkaline

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Recommended pH Range for Some Plants Flowers and Ornamental Shrubs Abelia 6.0 - 7.5 Grape Hyacinth 6.0 - 8.0 Ageratum 6.0 - 7.0 Honeysuckle 6.5 - 7.5 Alyssum 6.0 - 7.0 Hyacinth 6.0 - 8.0 Amaranthus 6.0 - 8.0 Liliums 5.5 - 7.0 Anemone 5.5 - 7.0 Lobelia 6.0 - 7.5 Anthirrhinium 6.0 - 7.0 Magnolia 5.0 - 6.0 Azaleas 4.5 - 5.0 Mignonette 5.0 - 8.0 Balsam 6.0 - 7.0 Morning Glory 6.0 - 7.5 Begonia 6.0 - 7.0 Nasturtium 5.5 - 7.5 Bottle Brush 6.0 - 7.5 Oleander 6.0 - 7.5 Cactus 7.0 - 8.0 Palms 5.0 - 6.5 Calendula 6.0 - 7.5 Pansy 5.5 - 6.5 Camellia 4.5 - 5.5 Passion Flower 6.0 - 8.0 Canna 6.0 - 8.0 Petunia 6.0 - 7.5 Carnation 6.0 - 7.5 Phlox 5.5 - 7.5 Chrysanthemum 6.0 - 7.0 Poinsettia 5.0 - 7.0 Cineraria 6.0 - 7.5 Poppy 6.0 - 7.5 Coleus 6.0 - 7.0 Portulaca 5.5 - 7.5 Cotoneaster 6.0 - 7.0 Primula 6.5 - 7.5 Crocus 6.0 - 8.0 Ranunculus 6.0 - 8.0 Cyclamen 5.5 - 6.5 Rose 6.0 - 7.0 Daffodil 6.0 - 6.5 Salvia 6.5 - 7.5 Dahlia 6.0 - 7.0 Stock 6.5 - 7.5 Daisy 6.0 - 7.0 Sweet Pea 7.0 - 8.0 English Ivy 6.0 - 8.0 Syringa 6.5 - 7.5 Foxglove 6.0 - 7.5 Viola 6.0 - 7.5 Freesia 5.5 - 7.5 Wallflower 6.0 - 7.5 Gentian 6.0 - 8.0 Wistaria 6.0 - 7.5 Gerbera 6.5 - 7.5 Zinnia 6.0 - 7.5 Gladiolus 6.0 - 8.0 Ornamental Trees Ash 6.0 - 7.5 Poplars 6.0 - 7.5 Elm 6.0 - 7.5 Weeping Willow 5.0 - 6.0 Locust 6.0 - 7.5 Agricultural Crops Clovers 5.5 - 7.0 Rice 5.0 - 6.5 Lucerne 6.0 - 8.0 Sunflower 6.0 - 7.5 Oats 5.5 - 7.0 Wheat 5.5 - 7.5

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Vegetables Artichoke 6.5 - 7.5 Lettuce 6.5 - 7.5 Asparagus 6.5 - 7.0 Marjoram 6.0 - 8.0 Bean 6.5 - 7.5 Onion 6.0 - 7.0 Beetroot 7.0 - 8.0 Parsley 6.0 - 7.0 Broccoli 6.0 - 7.0 Parsnip 5.5 - 7.0 Brussels Sprouts 6.0 - 7.5 Pea 6.0 - 7.5 Cabbage 6.5 - 7.5 Pumpkin 5.5 - 7.0 Carrot 6.5 - 7.5 Radish 6.0 - 7.0 Cauliflower 6.0 - 7.5 Shallot 5.5 - 7.0 Celery 6.0 - 7.0 Spinach 7.0 - 8.0 Chives 6.0 - 7.0 Swede 6.0 - 7.5 Cucumber 5.5 - 7.0 Sweet Corn 5.5 - 7.5 Garlic 5.5 - 8.0 Tomato 5.5 - 7.5 Leek 7.0 - 8.0 Turnip 5.5 - 7.0 Fruit Almond 6.0 - 7.0 Peach 6.0 - 7.5 Citrus 6.0 - 7.5 Plum 6.5 - 7.5 Gooseberry 6.5 - 7.5 Strawberry 6.5 - 7.5 Rock Melon 6.5 - 7.5 Walnut 6.0 - 8.0 Passion Fruit 6.0 - 8.0 Watermelon 6.5 - 7.5

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Australian Native Plants for Growing in Salt Contaminated Soil or with Salt Contaminated Water

Botanical Name Common Name Acacia acuminata Raspberry Jam Wattle Acacia harpophylla Brigalow Acacia longifolia Sydney Golden Wattle Acacia pendula Myall Acacia podalyriifolia Queensland Silver Wattle Acacia spectabilis Glory Wattle Angophora costata Smooth Barked Apple Atriplex nummularia Old Man Salt Bush Bauhinia carronii Bauhinia Brachychiton populneum Kurrajong Brachychiton rupestre Bottle Tree Callistemon citrinus Scarlet Bottlebrush Callistemon rigidus Stiff Bottlebrush Cassia artemisioides Silver Cassia Cassia sturtii Dense Cassia Dodonaea spp. Various Hop-Brushes Eremophila maculata Native Fuchsia Eremophila polyclada Flowering or False Lignum Eucalyptus calycogona Gooseberry Mallee Eucalyptus camaldulensis River Red Gum Eucalyptus citriodora Lemon Scented Gum Eucalyptus forrestiana Fuchsia Gum Eucalyptus leucoxylon Yellow Gum Eucalyptus leucoxylon var. rosea Red Flowered Yellow Gum Eucalyptus macrandra Long Flowered Marlock Eucalyptus ochrophloia Yapunyah Eucalyptus salmonophloia Salmon Gum Eucalyptus salubris Gimlet Gum Eucalyptus sideroxylon Mugga Ironbark Eucalyptus tessellaris Carbeen Eucalyptus torquata Coral Gum Eucalyptus viridis Green Mallee Gossypium sturtianum Desert Rose Grevillea robusta Silky Oak Hakea purpurea Purple Hakea Lagunaria patersonii Norfolk Island Hibiscus Melaleuca armillaris Bracelet Honey Myrtle Melaleuca bracteata White Clud Tree Melaleuca lincerufolia Snow in Summer Pittosporum phylliraeoides Berrigan or Butterbush

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Small Herbaceous Species, both Annual and Perennials, for Alkaline and/or Salty Soils

Flowers Vegetables Petunia Beetroot Gypsophilia Asparagus Carnations Spinach Calendula Silver Beet Statice Cabbage Hollyhock Cauliflower Marigold Broccoli Livingstone Daisy Tomato Straw Flowers Gazanias Mesembryanthemum spp. (Pig Faces) Succulents Many bulbs eg. Daffodils, Freesias, Snowdrops, Jonquils.

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Exotic Trees, Shrubs and Creepers for Alkaline and/or Salty Soils Botanical Name Common Name Atriplex cinerea Saltbush Atriplex ralimus Mediterranean or Saltbush Bougainvillea spp. Various named varieties Cupressus glabra Smooth Ariona Cypress Duranta repens Sky Flower Ficus carica Culinary Fig Fraxinus velutina Velvet Ash Jacaranda mimosifolia Jacaranda Lantana spp. Various named varieties Ligustrum spp. Privets Morus spp. Mulberry Nerium oleander Named Oleanders Olea africana Golden Olive Olea europaea Common Olive Olea spp. Fruiting Olive Phoenix dactylifera Date Palm Plumbago capensis Blue Plumbago Punica granatum Pomegranate Schinus molle Pepper Tree Spartium junceum Spanish Broom Tamarix aphylla Athel Tree Tamarix parviflora Tamarisk Vitis vinifera Grapes Wisteria spp. Wisteria Yucca spp. Yucca

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Australian Native Plants for Hot Dry Areas with a Minimum of Water Botanical Name Common Name Acacia acuminata Raspberry Jam Wattle Acacia aneura Mulga Acacia salicina Willow Wattle Bauhinia carrinii Bauhinia Brachychiton populneum Kurrajong Brachychiton rupestre Bottle Tree Callistemon brachyandrus Gold-Dust Bottlebrush Callistemon citrinus Scarlet Bottlebrush Callistemon rigidus Stiff Bottlebrush Cassia artemisioides Silver Cassia Cassia nemophila Desert Cassia Cassia nemophila Butterbush or Slipper Bush Cassia sturtii Dense Cassia Casuarina cristata Belah Casuarina cunninghamiana She-oak or River-oak Dodonaea boroniifolia Fern-leaf Hop-bush Eremophila latrobii Crimson Turkey Bush Eremophila maculata Native Fuchsia Eremophila polyclada False Lignum Eucalyptus camaldulensis River Red Gum Eucalyptus forrestiana Fuichsia Gum Eucalyptus leucoxylon Yellow Gum Eucalyptus leucoxylon var. rosea Red-Flowered Yellow Gum Eucalyptus macrandra Long-Flowered Marlock Eucalyptus sideroxylon Mugga Ironbark Eucalyptus tessellaris Carbeen Eucalyptus torquata Coral Gum Eucalyptus viridis Green Mallee Hakea purpurea Purple Hakea Pittosporum phylliraeoedes Butterbush or Berrigan

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Growing Better Lawns Keeping a lawn lush, green and healthy is not easy but it can be done. With careful use of fertilisers, soil amendments and watering, a lot of the problems in lawns can be prevented. The Water The quality of artesian bore water is one of the major problems in keeping a lawn vigorous. The problem is that there are small amounts of Sodium Bicarbonate and Sodium Chloride in the water. These salts accumulate in soils which are watered with the bore water. Two conditions results which are undesirable for lawn growth. 1. The soil becomes hard and water penetration becomes very slow. This accentuates

the salt problem because the affected areas are watered little and often, with much of the water lost by evaporation, and therefore wasted.

2. The soil becomes very alkaline. A pH level above 8.5 is commonly found. This

reduces plant growth and if very high (above 9.0) may cause unthriftiness and plant death.

Soils affected in this way develop a black scale on the surface. The grass is often

yellow and grows poorly despite frequent watering. Gypsum and Sulphur Gypsum (Calcium Sulphate) is a useful soil conditioner to offset the effects of salty bore water. It is quite cheap if it can be obtained in 50 kg bags. Gypsum does two things; the calcium substitutes for the sodium in the soil and softens the soil. The sulphate produces an acid reaction thereby reducing the alkalinity. Sulphur is much more powerful in reducing the alkalinity (only 1/5 as much as Gypsum is needed) but has little effect on soil hardness. Consequently, a combination of the two is useful to overcome the problems of watering with bore water.

Three handfuls of Gypsum and one of Sulphur per square metre are needed on

the lawn each year to offset normal watering with bore water. This is based on 11 handfuls per kilo (5 per lb). For anyone interested in large areas, this is equal to 800 kg/ha of Sulphur and 2500 kg/ha of Gypsum.

In garden beds the Gypsum and Sulphur should be dug in for faster results. For lawns this is not possible so watering in is the best way to incorporate the Gypsum and Sulphur. If a problem has already developed, and the soil is very hard, this treatment can be repeated two or three times during a summer season at monthly intervals. Gypsum will take a while to soften the soil as it will be incorporated only slowly into hard soil.

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Organic Matter Adding manure, or compost to soils will help to prevent soil becoming hard. It also improves soil structure and fertility and helps in maintaining a suitable pH. Watering Watering practices can reduce the build up of salts at the surface. The aim should be to minimise evaporation and the consequent waste of water.

1. Watering in summer should not be done during the heat of the day. More

than half of the water from sprinklers is either lost to evaporation or used rapidly by plants. This leaves only a little to wash through the soil to remove the harmful salts from the root zone of the plants. Watering at night is best.

2. Watering should be as infrequent as possible with large applications at each

watering. This will wet the soil to a considerable depth, thereby reducing evaporation and evenly distributing the salt throughout the soil. Fertilisers The most important nutrient required by lawns is Nitrogen. There are many different sources of this nutrient but Urea, Sulphate of Ammonia and Nitram are commonly used. Care should be taken with Nitrogen fertiliser to apply the right amount. Too much will damage the lawn. Sulphate of Ammonia is the best nitrogen fertiliser to use with bore water. The Sulphur counteracts the effects of bore water by acidifying the soil and the ammonia supplies the nitrogen. Every two years, a mixed fertiliser such as Tropic or Q5 containing Nitrogen, Phosphate and Potassium should be used. Fertilisers are often quite expensive when bought in small packets. Purchasing 20 or 50 kg bags is a much cheaper way of fertilising the lawn. Some of the fertilisers will absorb water from the air, and set hard. If opened bags are being kept from one year to the next, seal them with masking tape and put them in a dry place. Lawn Grubs

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Lawn grubs become prevalent in wet summers and are the most serious pests of lawns. The lawn grub is the larvae of a light grey brown moth measuring about 2.5 cm across the outstretched wing. The grubs feed at night and shelter below the lawn surface during the day. Their presence can be detected by placing a wet bag out on the lawn overnight and examining them early in the morning. If grubs are present they will be seen under the bag. Alternatively, a water jet from a hose will flush grubs to the surface. Lawn grubs like well kept lawns. Those which are watered and mowed frequently often suffer the worst damage. When the grubs are active, it is best to leave the mowing for sometime, add a Gypsum and Sulphur treatment or manure which will deter the moths for a while and let the lawn take its course. If the grubs become too bad then they can be sprayed. Trichlorfon sold as a Dipterex or Lawn Grub Killer is the best. Spraying in the late afternoon gives good results. Repeat sprayings two weeks apart may be needed while the grubs are present. Sheep and cattle dips should not be used to spray lawn because of the health risk to humans and pets. Caring For Your Citrus Trees in the Charleville Area Keep all grass away from base of trees and don't pile grass clippings or mulch too high up the trunk. Apply fertiliser two times per year, first application around June/July and the second in November/December. Use a general purpose fertiliser such as Tropic which contains all the essential nutrients. The rate of application depends on the age of the tree. For each year of age 0.5kg of fertiliser is applied to each tree. For example a two year old tree receives 2 x 0.5kg = 1 kg of fertiliser. A maximum of 3 kg is used for well grown trees. Use a trace element fertiliser designed for citrus once a year. Apply this in November/December following the directions on the pack. The fertiliser should be spread in a broad band around the tree. With young trees start about 10 cm fron the base of tree and continue out to about 50 cm past the edge of the canopy. Older trees have a longer root system and therefore the band should be wider. The effect of bore water on citrus trees results in the leaves yellowing, becoming dull and curling up. Later the margin may die back and turn brown particularly near the tips. Leaf fall and twig die back may be severe. Fruit tends to fall off and to be smaller than normal. To help this problem in citrus, as with the same problem around the whole garden, the use of Gypsum and Sulphur is ideal. Both Gypsum and Sulphur (Sulphur in the form of wettable Sulphur or Flowers of Sulphur) are available at most hardware shops. These should be applied at the rate of three handfuls of Gypsum to one of Sulphur per square metre.

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Common Pests and Diseases of Horticultural Crops in Western Queensland There are many diseases and pests which attack horticultural crops. Adequate control may be obtained by carrying out correct cultural practices and by a few established pest and disease control procedures. It is no accident that pest and disease problems are usually less severe in neat nurseries or gardens than in unkept ones. The chances of pests and disease attacking horticultural plants are reduced when the surrounding area is clean and in good order. Weeds not only compete with the crop for moisture and nutrients, but provide cover for pests and diseases. Diseased plants should not be dug into the soil or left to lie in the area, but should be burnt to destroy the disease causing organisms. Chemicals are no remedy for poor cultural practices, and the grower cannot hope to reap the full benefits from applied insecticides, fungicides or herbicides unless they practice correct cultural procedures. Lack of vigour because of low soil fertility is often associated with a disease outbreak. Attention should constantly be given to the provision of better soil fertility and improved soil structure for healthy plant growth. Practices which should be considered to help alleviate poor growth are: (i) The addition of artificial fertiliser at planting time and in the spring; (ii) The addition of animal manure or compost; and (iii) The building up of beds to give greater topsoil depth and better drainage. Other factors which may be the cause of lack of vigour include trace element deficiency, too much or too little moisture and nematode (eelworm) infestation. Crop rotation, that is, the planting of a succession of different types of crops, is a cultural practice which tends to prevent any undue increase in the pest and disease population associated with one particular crop. A two year rotation will greatly assist in suppressing soil-borne disorders. Most materials which are used for insect and disease control are also poisonous to humans. Therefore anyone using these materials should follow carefully the directions shown on the container, and observe all warning and precautions. When using some preparations, a mask should be worn to prevent inhalation of the vapour and protective clothing should be worn to prevent the spray from contacting the skin. When the operation is completed, clothing should be changed and any exposed areas of the skin should be washed thoroughly. When spraying edible crops a period of two weeks (or

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as otherwise directed) should be allowed between the last pesticide application and harvest. All treated fruits and vegetables should be thoroughly washed before use. Only those pests and disease which are common in this area and about which frequent enquiries are received, will be discussed in this review. Where trade names of chemicals have been quoted (italics), these are intended only as examples and should not be regarded as recommendations for particular commercial preparations. Most chemicals can be bought at hardware stores or stock and station agents. If the particular chemical which is required is not in stock, most shops will order what is needed. The application rates and concentrations which are stated on the container should be followed carefully.

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Citrus and Other Fruits (i) Queensland Fruit Fly The Queensland Fruit Fly (Batrocera tryoni) is a major pest in citrus orchards and home gardens. It also attacks stone fruits and the fruits of many native trees and shrubs. The adult fruit fly has a wasp-like appearance, the body being reddish-brown with lemon-yellow patches on the middle portion of the body. It is somewhat larger than a house fly. The insects may be easily seen in trees on sunny days when conditions are suitable for egg laying. The elongate - oval eggs are laid in batches of six or seven, under the skin of the fruit, usually shortly before ripening occurs. The larvae which emerge from the eggs feed on the flesh of the fruit and rots develop. The fruit eventually becomes unfit for consumption. Control - Spray when flies are observed, with dimethoate, for example Rogor or with fenthion, for example Lebaycid or Baytex. Dimethoate should not be used on Meyer lemons, Seville oranges or cumquats because it causes the tree to shed flowers, fruit and leaves. Both chemicals are toxic to bees, so avoid spraying when bees are active. An alternative (much less disruptive spray) would be yeast autolysate and maldison or chlorpyrifos applied at 50 ml per tree to a one square metre patch low down on the tree at weekly intervals. Also apply to nearby shrubs throughout the garden to increase the area treated. To make the spray add the following ingredients to one litre of water: Yeast 20 ml Maldison 5 ml or Chlorpyrifos 2 ml The use of a trap such as Dakpot containing maldison to indicate the presence of flies is recommended but it should be realised that this traps only the male fruit flies. (ii) Red Scale The main scale pest of citrus trees in Western Queensland is Red Scale (Aonidiella aurantii). This scale is flattish, reddish and circular with a diameter of about 2 mm. The female is wingless but the male is winged. Living young (crawlers) are produced by the female and these select their own feeding site and secrete the scale cover. Leaves, fruit, twigs, limbs and main branches may be attacked. The limbs and main branches are infested only in the case of open, poorly foliaged trees, as the scale shows a distinct preference for exposed, sunny sites. It is not usually found in appreciable numbers on limbs and main branches if the tree is carrying a reasonably good amount of foliage. Affected trees lack vigour, twigs die back and the fruit must be cleaned before use.

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(iii) White Wax Scale White Wax Scale (Grascardia destructor), also occurs and attacks a wide range of plants, both cultivated and native. This is a soft scale, the adult being about 5 mm in diameter, and is found mainly on mature wood. Living young are produced and these settle on the current seasons growth. Direct injury by the scale is less important than contamination of the fruit by a sooty mould which occurs in association with white scale. Control - These scales may be controlled by using an oil spray in mid November and again (if necessary) in late December. Do not apply during the heat of the day as the oil will cause severe burning and may even kill the plant. A narrow range oil such as Caltex Lovis or Ampol Octron may be better than white oil. For Red Scale use 150 ml of oil in 10 l water. For White Wax Scale use 90 ml of oil in 10 l water. Spray leaves, branches and trunks. Use early in the morning or late in the afternoon. Spraying during the heat of the day when temperatures are over 32oC can damage the trees. Do not spray when the trees are short of water. It is preferable to irrigate a few days before spraying. (iv) Citrus Aphid Citrus Aphids are soft, black or greenish black, sap sucking insects, about 3 mm (one tenth inch) in length, which are found on the young shoots and flowers. They cause distortion of the leaves which become crinkled and scorched in appearance, and dieback of the shoots occurs. Growth is retarded and fruit set affected. A characteristic feature of an aphid colony is a sticky fluid which is produced. This is partly sap from damaged plant tissues and partly a fluid secreted by the insects. The fluid provides a medium which is suitable for the growth of dark coloured moulds which can cover much of the surface of affected shoots. The fluid also attracts ants which are therefore found in association with aphid infections. Aphids should not cause too many problems for home gardens. Control - Lady birds will control aphids given half a chance. However, if growth is severely infested, Pirimor at 2.5g in 100 l applied to young growth is a biologically safe control method. (v) Citrus Gall Wasp This is a very small, black wasp which lays its eggs in young twigs during the spring and early summer months, causing conspicuous swellings or gall to develop on the twigs. Small white larvae emerge from the eggs and feed within the gall tissue of the twigs during summer and winter, until they are fully grown in spring. Each cavity in the gall contains a single larva. When fully grown the larvae pupate for a brief period and then the wasp emerges through holes made in the surface of the gall. The wasps appear in September and October and lay eggs within a week after emergence, usually

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on the tree on which they lived. Spread to other trees in slow because of this tendency to remain on the same tree. Control - None of the chemical methods so far tested have proved successful in commercially controlling this pest. One preventative action available is to prune infected parts during autumn and winter, when the insects are present only as larvae within the galls, before the emergence of the wasps in spring. Pruned twigs should be burnt. Another preventative step is to introduce parasites of the gall wasp to your garden. These are available from Mr Dan Papacek `Bugs for Bugs' 28 Orton Street, Mundubbera 4626. (vi) Spined Citrus Bug The Spined Citrus Bug is green with a prominant thorn or spine on each of the front corners of the body just near the head. They are about 20 mm long and green in colour. This makes them difficult to see amongst green foliage. The nymphs are yellow and black and become greener as they develop into adults. Both the adults and nymphs suck sap from the young shoots and fruit of lemon, orange and mandarin trees. Fruit drop results and even just a few bugs on each tree can cause severe damage. Control - Spray in the late afternoon with Maldison (Malathion) (2 ml/1L of water) and for each litre of water add 10 ml of white oil. Alternatively bugs could be hand picked from the tree. However, care should be taken to avoid the caustic fluid these bugs eject.

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Lawns (i) Lawn Grubs (Grass Caterpillars) The Lawn Grub which attacks most species of lawn grass is the larva of a light grey-brown moth measuring about 2.5 cm (1 inch) across the outstretched wings. The fully grown larvae (caterpillars or grubs) are about 2.5 cm long and greyish-green with darker spots on each body segment. They feed at night and shelter at the base of the turf mat during the day. The symptoms of grub infestation are a browning-off of the lawn and a dry, wilted appearance. The ground in the affected area is sometimes littered with pieces of leaf as well as the pellet-like excreta. Early warning of the lawn grub attack may be obtained by placing wet bags overnight on the lawn and examining them early next morning. If any grubs are present they will be found clinging to the bag or to the surface of the lawn beneath the bag. Control - Spray when the grubs are first noticed, before damage to the lawn is severe with trichlorfon (Dipterex or Lawn Grub Killer) or endosulfan (Endogrub). For small areas, such as home lawns, small quantities, applied with hand sprays, will be quite successful. Repeated sprayings are usually needed during summer. Best results are obtained by spraying in the late afternoon. This way most of the grubs are dead before morning and therefore not as attractive to birds. Also the chemical has largely dissipated before children and pets are on the lawn again. (ii) The Felted Grass Coccid The Felted Grass Coccid attacks a wide range of grasses including both green and blue couch. This pest is common in the area, but usually does not cause severe damage. It is usually found at the edges of lawns, particularly near concrete borders or steps. However, it sometimes spreads into the main part of the lawn, causing the grass to turn yellow and bare patches to develop. The insect is globular in shape, about 2 mm (1/16 inch) in diameter, with a white felt-like covering. It is found at or near ground level on stems or runners. Control - Use a dimethoate (Rogor)/white oil spray. (iii) Ants Ants can be very troublesome in lawns, destroying the turf and causing large bare patches, which are then suitable for invasion by weeds. Control - Ants are seldom troublesome where spraying to control lawn grubs is carried out. When necessary spray with fenthion (Lebaycid) at the recommended concentration.

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(iv) White Grubs These are the larvae of a Scarab beetle which lay eggs in the soil, frequently close to trees or tree stumps. The grubs are fleshy and white with a darker brownish head and blueish-grey terminal section of the abdomen. They are 2 cm to 2.5 cm (3/4 inch to 1 inch) in length and thicker than a pencil and are normally curled into a half-moon position. They feed on the roots of grasses and other plants. Affected plants lack vigour, brown off, are easily pulled out of the ground and death may result. If an affected plant is dug up, the grubs will be found among the roots which they are destroying. White grubs can cause the death of many vegetable and flower seedlings also. Control - Treat the soil surface with chlorpyrifos (Lorsban) at the concentration recommended on the container. As the grubs range in depth from just under the surface of the oil to a depth of 20 cm (8 inches) it is necessary to water the surface well after application to ensure that the insecticide is washed into all parts needing treatment. (v) Broad-leafed Weeds in Lawns There are many broad-leafed weeds which are pests in lawns, including thistles, daisies, cudweed and khaki weed. Khaki weed (Alternanthera repens) is very common and readily colonises bare patches. It has a thick tap root and a creeping habit. Roots form at each stem joint, and a mat-like growth is formed. The leaves are dull green and roundish. The flowers are straw coloured and when mature are stiff, with sharp points, and break off easily. If lawns are watered and fertilised regularly to promote vigorous grass growth, and if insect control is carried out when necessary, weeds are less likely to be troublesome. Control - A selective herbicide such as 2, 4-D is effective for the control of most broad-leafed weeds. Spraying should be carried out when the weeds are young and could be followed about a week later by an application of nitrogen, fertiliser, for example sulphate of ammonia to promote lawn growth. Many products containing 2, 4-D are marketed, some of these being, Shirweed 50 and Amicide 50. Kikuyu lawns are somewhat sensitive to 2, 4-D. Local experience has shown that a mixture of dicamba and MCPA gives effective control of broad-leafed weeds in kikuyu lawns without adversely affecting the grass growth. Commercial preparations which contain dicamba and MCPA include Hortico Clover and Bindi Lawn Weeder, Yates Bindi Weed Killer and Selley Weed-B-Gon.

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Trees and Shrubs (i) White Cedar Moth (or Hairy Grub) This pest is very common in Western Queensland and the larvae may completely defoliate trees, usually during the period from January to March. The moth lays its eggs on the bark and foliage. The brown, hairy larvae are 2.5 cm (1 inch) to 4 cm (1 1/2 inches) long, and feed during the night sheltering near the base of the tree during the day. In the evening they may be seen, in large numbers, moving up the trunk of the tree. When full grown they find a sheltered place under bark or in crevices of posts or buildings and there, construct their pupal cocoons. When a tree has been completely defoliated, the larvae will leave it and can often be seen moving in procession to another tree. White cedar appears to be the only host of this pest. Contact with the hairs on the grubs causes skin irritation to some people. Control - The larvae may be trapped in a folded bag, placed around the trunk of the tree, and then destroyed. Alternatively a maldison (Malathion) foliage spray may be used, or the grubs may be sprayed where they shelter on the ground during the day, or when they are moving up the trunk in the evening. (ii) Wood Borers There are a number of different species of borers, but the damage caused by each is similar and is treated in the same way. The injury to the tree usually occurs near a branch fork, or where the bark is cracked or has been broken. The hole made by the borer in the tree is usually surrounded by wood dust and sap from the tree and web like fibres left by the borers. Control - Prune and burn infested twigs and small branches. Where the borer holes occur in large branches or in the trunk, trim around the damaged area to properly expose the hole, but do not extend the damaged area during the trimming. Then brush the area clean and insert flexible copper wire into the hole twisting it to kill any larvae which are present. Inject methylated sprits, or maldison at the recommended concentration into the hole, by means of an eye dropper or an oil can. Seal pruned twigs and injured areas with bitumastic paint, heavy greases, grafting mastic or creosote. (iii) White Scale Insects These are similar to the white scale found on citrus trees and may be controlled by use of the same white oil spray. (iv) Powdery Mildew

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This fungus occurs on many shrubs in other areas, but in this area is seldom seen on shrubs other than the Crepe Myrtle (Lagerstroemia). It occurs as grey floury patches on leaves and twigs, and the leaves are often grossly distorted. Control - Dust with Sulphur, when first noticed and as necessary after that. (v) Grasshoppers and Locusts Several species occur in this area from time to time and can be very destructive to most horticultural crops if they are present in plague proportions. In the last few years they have caused severe defoliation of trees and shrubs in home gardens, therefore they have been included in this section. The main species are the Australian Plague Locust and the Spur Throated Locust. Control - Control is difficult unless it is carried out before the grasshoppers reach the flying stage. When flying grasshoppers invade the garden in large numbers, some control can be obtained by using an insecticide spray such as maldison (Malathion), fenitrothion (Folithion 1000 Insecticide Spray), or diazinon (Diazinon 800).

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Vegetables (i) Insect pests of Curcurbits (Pumpkin and Melon Family) (a) Pumpkin Beetles The Banded Pumpkin Beetle is orange-yellow, with two large black spots on each wing cover. It is about 6 mm (1/4 inch) long and 3 mm (1/8 inch) broad. The Plain Pumpkin Beetle is slightly larger and more slender and is uniform yellowish-brown colour. Pumpkin beetles are particularly destructive to the seedlings, flowers and small fruit of curcurbit crops, and the growth of established plants may be checked by the beetles feeding on the leaves, flowers and newly formed fruit. They show a distinct preference for the young leaves and tendrils and often cluster together when feeding. Leaves may be eaten so that only the main veins remain. When the beetles feed on flowers, fruit set is affected and when a young fruit is attacked it will wither and fall. The small, oval, yellow eggs are laid on dead leaves or small clods of earth under the food plants. After about ten days, the long, narrow, cream coloured larvae hatch and attack the main roots system and subsidiary roots, and the greater part of the body remains outside and may be easily seen when infested roots are examined. The roots become swollen, discoloured and mis-shapen and plant growth is retarded. The larvae also penetrate the lower surface of fruit which are touching the ground, and produce blemishes through which fungi can enter the tissues, causing rots to develop as the fruit ripens. When full grown (12 mm) the larvae pupate in the soil and the beetle later emerges. Control - Spray with carbaryl (Bugmaster)at the dilution rate of 0.1 per cent. (b) Leaf Eating Ladybirds in Curcurbits This beetle is oval in shape, about 6 mm (1/4 inch) long and yellowish-brown in colour. The wing covers are marked with from 24 to 28 conspicuous black spots which distinguish it from the harmless or beneficial ladybirds which are found on other plants. These have fewer or no spots. Its movements are sluggish and it does not fly readily. The oval, yellowish eggs are laid in clusters on the under surface of foliage or developing fruit. The yellowish larvae emerge and feed on nearby leaves. These larvae, when fully grown are about 1 cm (1/3 inch) long and the body is profusely covered with dark, many branched spines, giving a hairy appearance. Pupation occurs on the host plant or in adjacent trash. All stages of this pest may be present on the food plant, mainly the foliage, although flowers and developing fruit may be injured. The beetles feed mainly the upper surface of the leaves. The larvae are confined to the underneath of the leaves, destroying the green tissues and leaving veins linked to be a grid-like, almost colourless film. Injury lowers the yield and exposes the maturing fruit to the sun, causing scald. The larvae also damage the rind of the fruit. Control - Spray with carbaryl (Bugmaster) at a dilution rate of 0.1 per cent.

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(ii) Fungal Diseases of Curcurbits These usually only occur in this area in unusually wet seasons. (a) Powdery Mildew of Cucumber and Rockmelon White fungus growth on stems, leaf stalks and leaves. Control - Spray with Oxythioquinox (Morestan) when noticed and thereafter at 7 to 10 days intervals, as necessary. Other suitable fungicides are Triadimefon (Bayleton Garden Fungicide) and Chlorothalonil and Fenarimol (Zero Fungicide). It is good to alternate the use of fungicides to minimise the risk of resistance to fungicides developing. (b) Powdery Mildew of Marrow and Pumpkin White patches on older leaves and stems, causing loss of foliage. Control - Dust with dusting Sulphur when disease appears and weekly thereafter as required. Oxythioquinox (Morestan) or Triadimefon (Bayleton Garden Fungicide) are also suitable. (c) Downy Mildew of Cucumber and Rockmelon Yellow or brown, angular spots, starting on older leaves and causing defoliation. Control - Spray with Chlorothalonil and Fenarimol (Zero Fungicide), Mancozeb (Dithane M-45) or Zineb (Zineb 80) fungicide spray, when noticed and thereafter at 7 to 10 days intervals, as necessary. The disease is favoured by warm moist weather. (iii) Aphids on Vegetables Small, soft insects, usually green or greenish black, clustered under leaves, or on shoots or flower stalks and buds. Control - Spray with dimethoate (Rogor). (iv) Caterpillars or Grubs on Vegetables There are many different types which occur from time to time, and which can cause sever damage. Control - Most species of these pests can be controlled by spraying with carbaryl (Bugmaster) diazinon (Diazinon 800) or endosulfan (Endosulfan). (a) White Cabbage Butterfly or Cabbage Grub

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The larvae of this butterfly are velvety green grubs, up to 4 cm (1.5 inches) long, which devour the leaves of cabbages and related species. They leave behind obvious black excrement. Control - Dipel Bacterial Spray should be used when grubs or butterflies are seen. (v) Nematodes - (eelworms) These pests are not confined to vegetables, but attack flowers, shrubs and trees as well. However, as most of the enquiries received here have been about root knot nematodes in vegetables, they will be dealt with in this section. Vegetables which are grown in this area and which are affected by root knot nematodes include beetroot, cabbage and related crops, carrots, parsnips, lettuce, tomatoes and curcurbits such as pumpkins, melons and cucumbers. Nematodes are microscopic, the majority of soil nematodes ranging in length from 0.5 to 2 mm and in width from 10 to 50 microns. The above ground symptoms of root nematode infestation are lack of vigour and reduced tolerance to drought. With trees, foliage may be small and leaf-drop and dieback may occur. Below the ground, numerous irregular swellings or galls on the roots are a characteristic symptom. Where fleshy tissues are present, extensive tissue destruction causes rot to develop. Excessive root branching may occur, causing the development of a densely matted root system on plants which are normally strongly taprooted. Control - Cultural Practices. Crop rotation with resistant crops is effective in reducing the damage caused by many nematodes. The incorporation of large amounts of organic matter into the soil and the use of an organic surface mulch reduces the severity of injury because these practices create conditions which are favourable to the natural enemies of nematodes. Organic material should be incorporated into the soil well before planting and crops should not be planted until decomposition is complete. The use of a period of bare fallow, with the soil kept weed free, especially during hot weather, will reduce the nematode population. In orchards and vineyards the use of nematode resistant rootstocks, for example, certain varieties of peach and grape, help to overcome the nematode problem Chemical Control - The nematicide fenamiphos (Nemacur Granular NematicideR) can be applied at or before planting to control nematodes in annual vegetables and flowers. The granules are spread evenly over the bed, forked into the top 15 cm and watered in. For established trees and shrubs, granules are sprinkled on the soil in the root zone and watered in. Nemacur Granular NematicideR is poisonous and should be handled with care, as per label directions.

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Roses and Other Flowers (i) Dieback in Roses This is a fungal disease which is common in all districts. The stem dies back from a cut end, turning dark brown or black. There is usually a purplish band between the live and dead material. Control - As soon as this disease is noticed, prune well below the affected parts, dipping the blades of the secateurs into a fungicide liquid after each cut. Then swab the freshly cut ends with a paste of a copper fungicide, for example Bordeaux Powder Fungicide. Vigorous plants are less susceptible to attack by this fungus, therefore correct fertilisation and the control of insect pests help to lessen the incidence of dieback. (ii) Caterpillars and other Leaf and Bud Eating Pests These occur on most flowers from time to time. Some can severely defoliate plants and destroy flower buds completely. Control - A trichlorfon (Dipterex) spray is effective against most of these pests. Treat when the pests are first noticed, and thereafter weekly, or as necessary. (iii) Powdery Mildew This is a fungus which can be troublesome on many flowers which grow in this area, including roses, nasturtiums, sweet peas, zinnias and verbena. It starts as whitish spots and develops into grey or white floury patches on leaves, stems and flower buds. Distortion of the affected parts may occur and patches may die. Control - Dust with dusting Sulphur, or apply triforine or chlorothalonil and Fenarimol (Zero Fungicide), when noticed and weekly thereafter as required. When treating roses, particular attention should be given to the underside of the leaves. (iv) Twospotted Mites Twospotted Mites live in colonies beneath the leaves of roses. They are very small (0.5 mm long) and can be seen with a hand lens. When the population is very high their webs become visible and the leaves yellow. The life cycle is very short and in summer populations of mites can double in about a week, this is the reason for mite outbreaks in early spring. Control - Mites on completely unsprayed roses are often controlled by natural enemies and are not always a problem. If they do become a problem dicofol (Kelthane) can be used or predatory mites may be introduced. The latter is available from Bio Protection Pty Ltd, PO Box 35, Warwick 4370, Telephone (076) 661592, Facsimile (076) 661639.

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Which Pesticide to Buy? (Reprinted from the Queensland Agricultural Journal July-August 1988) Using pesticides alone to protect plants against pests is not the most effective strategy. Management of pests, rather than eradication, is more efficient. Plants can tolerate some pest activity before resort to pesticides becomes necessary. Removing dead and rotting plant material and keeping the garden free of weeds that may harbour pests helps prevent them multiplying. It may even be possible to remove some insects from the plants by hand or with a hose. But, when pests are visible in damaging numbers and a pesticide application is needed, choose the pesticide carefully. With so many garden pesticides available, the home gardener can sometimes be uncertain which best suits his needs. A given pest can often be controlled by a variety of chemicals. Some pesticides are selective, being effective against only a few pests. Choosing such chemicals may lead to a cupboard full of products, each used occasionally and eventually deteriorating with lengthy storage. A better plan is to choose chemicals that have a broad range of activity against a number of pests. In this way, pesticides in store are fewer and the gardener gets best value for money. The formulation of pesticides must also be considered when choosing. Dusts or sprays can be used to control pests. Dusts do not need mixing and are easy to apply. However, it is sometimes difficult to get good coverage of some plants with a dust, and it is easily washed off by rain or overhead watering. Spraying gives a better and more even coverage of the plant, and therefore more efficient control. Recently, `ready-to-use' spray formulations which require no mixing or dilution have become available in aerosol and atomiser packs and may be useful in certain situations. Biological pesticides are also available to the home gardener and may be an alternative choice in some situations. Such pesticides enable the gardener to conduct germ warfare against certain pests by spraying them with disease organisms specific to these pests. For example, Dipel (R) (a bacterium) may be used to control leaf-eating caterpillars. The choice chemical pesticides includes carbaryl, dimethoate, Sulphur, pyrethrins, dicofol, white oil, fenthion, trichlorfon and fenamiphos. Metaldehyde and methiocarb are used specifically for slugs and snails. All these chemicals appear on the labels of popular pesticides, and all are of comparatively low human toxicity if used correctly. Carbaryl, a broad-spectrum insecticide with a short residual life, can be used close to harvest. It is effect against some caterpillars and leaf-eating beetles and ladybirds, but does not control caterpillars attacking plants of the cabbage family. Dimethoate is also a broad spectrum insecticide and miticide. It is effective against fruit fly, aphids, thrips, jassids and mites. Fenthion also controls fruit fly. Though lacking as wide a range of activity as dimethoate, it does not injure Meyer lemons and cumquats as does dimethoate.

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Sulphur controls mites on many garden plants. It should not be used in hot weather as it tends to burn tender plant tissue. Pyrethrin is a useful contact insecticide as it can be applied to within one day of harvest. It is relatively less toxic to humans, but not as effective as some other formulations. Dicofol controls mites on many garden plants. White oil is an important component in sprays for citrus scale control. Trichlorfon may be used to control caterpillar pests (for example bean pod borer, cutworms, lawn grubs and macadamia flower caterpillar) and fruit spotting bugs. Fenamiphos is a nematicide effective against pests such as root knot nematode. Its granular formulation is considered the safest form to use. However, it should always be handled with great care, including the use of protective clothing. The home gardener can deal with most pest infestations with these chemicals. There is duplication of activity against some pests, and some of these materials could be omitted without seriously interfering with the overall range of protection. For all chemicals the same rules apply: keep all safely locked up and secure from children, and always be careful when handling or mixing pesticides. One reason for their inclusion on this list is that all chemicals are fairly safe to use. But all insecticides are poisonous to man in some degree. Treat them with respect.

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The Easy Guide to Chemicals

est Chemical Trade Name P INSECTS Ants Diazinon PCO Neocid 800 Chlorpyrifos Deter Aphids Maldison Malathion Pirimicarb Pirimor Endosulfan Endopest Cabbage grubs Diazinon Diazinon 200 Fruit Fly Dimethoate Rogor Gall Wasp Pruning and burning Hairy grubs and Maldison Malathion or Maldison Wood borers Lawn grubs and Endosulfan Endogrub or Endopest Cutworm Trichlorfon Dipterex, or Lawn grub killer Leaf miners Dimethoate Rogor Endosulfan Endosulfan Locusts and Chlorpyrifos Lorsban Grasshoppers Fenitrothion Folithion 1000 Diazinon Diazinon 800 or Gesapor Carbaryl Carbaryl Mites Omethoate Folimat Maldison Malthion Scale Insects Maldison Malathion or Maldison White oil White oil Termites Chlorpyrifos Deter or Dursban White grubs Chlorpryifos Lorsban

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est Chemical Trade Name P FUNGI, MILDEW OR NEMATODES Downy mildew Chlorothal + Fenarim Tayzero Banalaxyl + Mancozeb Galben Nematodes Fenamiphos Nemacur Granular Nematicide Powdery mildew - Cucurbits Oxythicoquinox Morestan Chlorothalonil & Zero Fungicide Fenarimol Dusting Sulphur Various Triadimefon Bayleton Garden Fungicide Roses Triforine Saprol Chlorothalinol & Fenarimol Tayzero Sulphur Sulphur spray WEEDS Broad leaf weeds 2, 4-D Amicide 50 or Shirweed 50 Grass Type weeds Glyphosphate Roundup or Zero This list is only a guide and other chemicals may well be available.

Always read the label directions then follow them.

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Notes

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Notes

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Notes