Garden Pests and Diseases Control

7/30/2019 Garden Pests and Diseases Control

1/28

P a g e | 1

PESTS DISEASES &

CONTROL

Capt. S.K.BHANDARI

Mobile: 9358525643

ASFIC


2/28

P a g e | 2

INSECTS PESTS DISEASES AND CONTROL

INDEXSUBJECT PAGE

Pesticides Introduction 3, 4Aphids 5, 6Mite 7, 8Caterpillars 8, 9Leafhopper 10, 11Leafminer 11, 12Mealybug 13, 14Nemotode 14, 15, 16

Scale 16, 17Thrips 18, 19, 20Stink Bugs 20, 21Weevels 22, 23Whiteflies 23, 24, 25Powdery Mildew 25, 26, 27Downey Mildew 27, 28


3/28

P a g e | 3

Pesticides IntroductionTerminology and DefinitionsPests Organisms such as insects, rodents, nematodes, fungi, weeds, birds, bacteria, viruses, etc., whichdamage the crops and reduce yield. Pests are injurious to human health and/or farmers economic efforts.

Pesticides Chemicals or mixtures of chemicals that are used for killing. repelling, mitigating or reducingpest damage.Herbicides Substances used for inhibiting growth of plants, plant parts, or to kill/destroy the plants.Defoliants Substances that initiate leaves to fall.Desiccants Substances that cause plant tissue to dry up.Fungicides Substances that prevent, destroy or inhibit the growth of fungi in crop plants.Insecticides Substances that prevent, inhibit, destroy, kill insects.Rodenticides Substances that prevent, inhibit, destroy, kill rodents (Class Mammalia)Miticides/Acaricldes Substances that prevent, inhibit, destroy, kill or mitigate mitesNematicides Chemicals that prevent, repel, inhibit or destroy members of the Class (Nematodes)Molluscicides Prevent, repel, inhibit or destroy members of the Phylum Mollusca such as snails.

Formulation The form in which a pesticide is sold for use.Active ingredient (a.i) is a part of a pesticide formulation which is the actual toxicant sometimes referredto as "technical grade" or "basic pesticide"Inert ingredients Substances, other than the active ingredient, which constitute a pesticide formulation.Classification of PesticidesPesticides may be classified according to:a) the target pest species.b) their chemical constitutionc) their site of actionSystemic poisons and Contact poisonsThese poisons enter the body directly through the cuticle by contact with the treated surface of the foliage,

stem, etc. These poisons act on the nervous system of the pest. These may also be applied directly on tothe body of the pest as a spray or dust. Examples: benzene hexachloride. dichloro diphenyl trichloroethane, endrin, quinalphos, carbamates, etc. Some of the known pesticides derived from plants also havecontact action.Examples: pyrethrum, rotenone, sabadilla. nicotine, etc.Stomach poisonsStomach poisons enter the body of the pest through the mouth during feeding into the digestive tract fromwhere these are absorbed into the systems. Stomach poisons are more effective against chewing insectsand useful in controlling insects with siphoning or sponging types of mouth parts (housefly for an example).Examples: dieldrin, sulfur, lead arsenate, etc.Classification based on site of action

By segmenting insecticides/acaricides and fungicides separately, insecticides/ acaricides can be classifiedon the basis of their routes of entry into the body system of the target pest.A. For spraying after mixing with water/oili) Emulsifiable concentrates (EC)ii) Wettable powders (WP or WDP)iii) Ultra low volume concentrates (ULV)

B. For dry application directly from the container


4/28

P a g e | 4

i) Dusts (D)ii) Granules (G)iii) Encapsulated granulesC. For application as a gas or vapori) Fumigants

ii) Smoke generators or tablets that vaporizeiii) Aerosols and pressurized spraysD. Other formulationsi) Seed protectants (dry or liquid)ii) Baits for rodents, slugs, flies, cockroaches, etc.These are concentrated solutions of the technical grade material containing an emulsifier to help theconcentrate mix readily with water for spraying. The emulsifier is a detergent that causes the suspension ofmicroscopically small oil droplets in water, to form an emulsion. When an emulsifiable concentrate is addedto water and agitated (i.e., stirred vigorously), the emulsifier causes the oil to disperse uniformly throughoutthe carrier (i.e., water) producing an opaque liquid. Liquid formulations are easy to transport and store, andrequire little agitation in the tank. However, care must be exercised in handling the toxic concentrates.

Emulsifiable concentrates (EC)Type of FormulationsFormulations contain the a.i. in a definite concentration together with other materials such as inertcarriers, emulsifiers, wetting agents, solvents, thickeners, encapsulants, etc. According to the intendedmode of application, the common formulations can be grouped as follows:They have unsuitable physical characteristics. They are generally waxy or lumpy solids or viscous liquids.In this form, they are difficult to apply.They have high purity levels and hence the required dose is difficult to disperse. The quantity involved isvery small to be evenly and effectively dispersed over a specified area.The toxicity of the a.i. is much higher compared to the formulations. Thus, application of a.i. is not onlyhazardous but also needs specialized tra ining and knowledge in handling.The a.i. does not have the ideal physiochemical characteristics which the formulations have.Pesticides are first manufactured as technical grade (active ingredient or a.i). In this form, they areunsuitable for direct use because of the following reasons:Pesticides nomenclaturePesticides usually have three different names.i) Chemical name or the name of the active ingredient in pure form,ii) Common name, andiii) Trade name/brand name or proprietary name.

APHIDS


5/28

P a g e | 5

Aphids Aphids Aphids Aphids

Aphids are small, soft-bodied insects with long, slender mouth parts that they use to pierce stems, leaves,and other tender plant parts and suck out plant fluids. Almost every plant has one or more aphid speciesthat occasionally feeds on it.IDENTIFICATIONAphids may be green, yellow, brown, red, or black depending on the species and the plants they feed on. Afew species appear waxy or woolly due to the secretion of a waxy white or gray substance over their bodysurface. Generally adult aphids are wingless, but most species also occur in winged forms, especially whenpopulations are high or during spring and fall. Although they may be found singly, aphids often feed indense groups on leaves or stems.

LIFE CYCLEAphids have many generations a year. Most aphids in mild climate reproduce asexually throughout most orall of the year with adult females giving birth to live offspring (often as many as 12 per day) without mating.Young aphids are called nymphs. They molt, shedding their skins about four times before becoming adults.There is no pupal stage. Some species mate and produce eggs in fall or winter, which provides them amore hardy stage to survive harsh weather. In some cases, these eggs are laid on an alternative host,usually a perennial plant, for winter survival.

When the weather is warm, many species of aphids can develop from newborn nymph to reproducing adultin 7 to 8 days. Because each adult aphid can produce up to 80 offspring in a matter of a week, aphidpopulations can increase with great speed.

DAMAGELow to moderate numbers of leaf-feeding aphids are usually not damaging in gardens or on trees.However, large populations cause curling, yellowing, and distortion of leaves and stunting of shoots; theycan also produce large quantities of a sticky exudate known as honeydew, which often turns black with the


6/28

P a g e | 6

growth of a sooty mold fungus. Some aphid species inject a toxin into plants, which further distorts growth.A few species cause gall formations.

Aphids may transmit viruses from plant to plant on certain vegetable and ornamental plants. Squashes,cucumbers, pumpkins, melons, beans, potatoes, lettuces, beets, chards, and bok choy are crops that often

have aphid-transmitted viruses associated with them. The viruses cause mottling, yellowing, or curling ofleaves and stunting of plant growth. Although losses can be great, they are difficult to prevent through thecontrol of aphids because infection occurs even when aphid numbers are very low: it only takes a fewminutes for the aphid to transmit the virus while it takes a much longer time to kill the aphid with aninsecticide.

A few aphid species attack parts of plants other than leaves and shoots. The lettuce root aphid is a soildweller that attacks lettuce roots during most of its cycle, causing lettuce plants to wilt and occasionally dieif populations are high. The lettuce root aphid overwinters as eggs on poplar trees, where it produces leafgalls in spring and summer. The woolly apple aphid infests woody parts of apple roots and limbs, often nearpruning wounds, and can cause overall tree decline if roots are infested for several years.

MANAGEMENTAlthough aphids seldom kill a mature plant, the damage and unsightly honeydew they generate sometimeswarrant control.CHEMICAL CONTROLInsecticidal soap, neem oil, provides temporary control if applied to thoroughly cover infested foliage. Toget thorough coverage, spray these materials with a high volume of water and target the underside ofleaves as well as the top. Soaps, neem oil, only kill aphids present on the day they are sprayed, soapplications may need to be repeated.Many other insecticides are available to control aphids in the home garden and landscape,including foliar-applied formulations of malathion, permethrin and acephate (nonfood crops only).Acephate has systemic activity, which means it moves through leaves, thus it can be effectivewhere aphids are hidden beneath curling foliage. The soil-applied systemic pesticide Acephate issometimes applied in roses for aphid control, but it is a highly toxic material to people. Use 1 partAcephate in 1 liter water.

When considering application of pesticides for aphid control, remember that moderate populations of manyaphids attacking leaves of fruit trees or ornamental trees and shrubs do not cause long-term damage. Lowpopulations can be tolerated in most situations and aphids will often disappear when natural enemies or hottemperatures arrive. Often a forceful spray of water or water-soap solution, even on large street trees,when applied with appropriate equipment, will provide sufficient control.

MITES


7/28

P a g e | 7

Mite Eggs Mite Red Mite Foliage Damage Mite Colony

These small creatures can normally not be seen by the naked eyes. It is only after the damage occurs thatwe observe that the cause is mites.IDENTIFICATIONThere are over 20 different types of mites but the common ones are cyclamen and broad mites. Thesemites are about one-fourth the size of spider mites and can't be seen without a microscope or a 20Xmagnifier. Adult cyclamen mites can be translucent white, pinkish orange, or pale yellow. Broad mites areoften translucent, yellowish, or greenish, and female broad mites have a white stripe down the center oftheir back. Broad mites have a tapered body that is widest between their second pair of legs and morenarrow toward the rear. Cyclamen mites have sides that are more nearly parallel, not sharply tapered.LIFE CYCLE

The mites, such as the two-spotted spider mite, lay as many as 100 to 200 eggs on the undersides ofleaves on one of approximately 180 host plants. Host plants include field crops, ornamental plants, weedsor house plants. The eggs take up to 20 days to hatch, although they may hatch in just a few days if theweather cooperates. Cool-weather spider mites often spend the entire winter in the egg stage whileattached to the host plant. The eggs begin hatching in the spring. The mite eggs hatch into tiny larvae withrounded bodies and three pairs of legs, a stage they stay in for several days while they rest and feed. Next,they molt into a nymph with four pairs of legs, resting and feeding before molting into a second nymphstage. Within a few days, the second-stage nymphs became adults. The entire process from egg hatchingto adult stage takes between 7 and 14 days. Adult spider mites sport four pairs of legs extending off asingle, oval body. Female spider mites have rounded abdomens while males have pointed abdomens.Some mites, such as the clover mite, only live for a few weeks as long as weather conditions stay in their

favor. Female two-spotted mites often live longer, spending the winter in a protected spot.

DAMAGE


8/28

P a g e | 8

Cyclamen and broad mites infest many hosts such as begonia, dahlia, geranium, gerbera, and verbena.Infested leaves become cupped, curled, dwarfed, and thickened. Leaves or flowers may becomediscolored, bronzed, or stiff. Infested buds discolor, deform, or drop. Internodes may be short, giving plantsa stunted or tufted appearance. When they feed on the sap of houseplants, spider mites cause damage bybiting into them. Spider mite infestation causes light speckles to appear on leaves. Heavy infestations can

stunt and even kill houseplants,MANAGEMENTEarly detection of spider mites, before damage is noticed, is important. The tiny spider mites can bedetected by taking a piece of white paper or cardboard and striking some plant foliage on it. The mites canbe seen walking slowly on the paper. If 10 or more mites per sample are common, controls may be needed.Syringing Since rainy weather seems to knock off spider mites, using a forceful jet of water from a hose(syringing) can perform the same task. A regular syringing can keep spider mites under control on mostornamental plants in the landscape. This technique also helps conserve natural predators.Chemical Control - "Soft Pesticides". Most spider mites can be controlled with insecticidal oils and soaps.The oils, both horticultural oil and dormant oil, can be used. Horticultural oils can be used on perennial andwoody ornamentals during the summer at the 1 to 2 percent rate. Higher rates of horticultural oil (3 to 4

percent) or dormant oil are useful for killing mite eggs and dormant adults in the fall and spring. Theinsecticidal soaps are useful in the warm season. Remember that mites are very tiny and soaps andoils work by contact only. Therefore, thorough coverage of the plant is necessary for good control.There are few products available to the gardener - Dicofol , Acephate), dimethoate , chlorpyriphosand malathion.

Broad and cyclamen mites are difficult to control with pesticides because they are protected from sprays bytheir habit of feeding in buds or within distorted tissue. Regularly inspect plants and disinfest or dispose ofinfested plants. Establish new plantings from mite-free stock and never plant new plants near infested ones.Horticultural oils, available at many garden supply stores, are the most effective spray against mites.

Insecticides are also effective. If your plant is severely infested with spider mites use ofDicofol ,Acephate), dimethoate , chlorpyriphos and malathion can control them. Spray 1 ml of the pesticide

in 1 liter of water for 15-20 days with a gap of 3-4 days..CATERPILLARS

Caterpillar Eggs Caterpillar Common Caterpillar Red Caterpillar Moth

Most flowers are susceptible to damage from caterpillars of one or more species. Caterpillars are theimmature or larval stage of moths and butterflies. Only the larval stage chews plants. Although adults

consume only liquids, such as nectar and water, they are important because they choose which plants tolay eggs on. Larvae have three pairs of legs on the thorax (the area immediately behind the head) and leglike appendages on some, but not all, segments of the abdomen.LIFE CYCLEMoths and butterflies have complete metamorphosis and develop through four life stages. Adults haveprominent, delicate wings covered with tiny scales that rub off and appear powdery when touched. Aftermating, the female moth or butterfly lays her eggs singly or in a mass on or near the host plant or nearbysoil. Eggs usually hatch in several days. The emerging larvae move singly or in groups to feeding sites on


9/28

P a g e | 9

the plant.Most caterpillars eat voraciously and grow rapidly. Some feed almost continuously. Others, such ascutworm larvae, hide in the soil during the day, emerging to feed at night. Caterpillars shed their old skinsabout five times before entering a nonactive pupal stage. Some species pupate in silken cocoons, andmost species pupate in a characteristic location, such as on the host plant or in litter beneath the plant.

The adult moth or butterfly emerges from the pupal case after several days to several months, dependingon the species and season. Some common caterpillars have only one generation per year outdoors; otherspecies have several generations each year and can cause damage throughout the growing season.

DAMAGECaterpillars chew irregular holes in foliage or blossoms or entirely consume seedlings, young shoots, buds,leaves, or flowers. Some caterpillars fold or roll leaves together with silk to form shelters. Caterpillar feedingcan kill or retard the growth of young plants.

MANAGEMENTHandpick. Eliminate nearby weeds, which may host caterpillars. Provide proper cultural care to allow olderplants to outgrow and replace any damaged tissue after infestations are controlled.

Uses systemic products such as Acephate (1 ml in 1 liter water) spray, which easily eliminate anycaterpillar that is feeding on ornamental plants. When heavily infested shrubs were sprayed with asolution of Imadaclorprid or use Permethrin. These applications should be made at about 10 to 14day intervals to effectively kill the different generations of caterpillars that are probably present.The effect of Imadaclorprid spray 0.050 ml in 1 liter of water last for 6 months.

LEAFHOPPERS


10/28

P a g e | 10

Leafhopper Eggs Leafhopper Nymphs Leafhopper Adult Leafhopper DamageRose Leafs

Leafhoppers feed on several flower hosts such as aster, chrysanthemum, dahlia, and nasturtium. Mostadult leafhoppers are slender and less than or about equal to 1/4-inch long. Some species are brightlycolored, while others blend with their host plant. Leafhoppers are active insects; they crawl rapidlysideways or readily jump when disturbed. Adults and nymphs and their pale cast skins are usually found onthe underside of leaves.IDENTIFICATIONLeafhoppers may sometimes be confused with aphids or lygus bugs. Look for leafhoppers or their castskins on the undersides of affected leaves. Look at their actions; they are faster than aphids and runsideways and jump. Lygus bug nymphs are light green and also move much faster than aphids. They can

be identified by their red-tipped antennae. Aphids can be distinguished by two tubelike structures, calledcornicles, protruding from the hind end.LIFE CYCLEFemales insert tiny eggs in tender plant tissue, causing pimplelike injuries. Wingless nymphs emerge andmolt four or five times before maturing in about 2 to 7 weeks. Leafhoppers overwinter as eggs on twigs oras adults in protected places such as bark crevices. In cold-winter climates, leafhoppers may die duringwinter and in spring migrate back in from warmer regions. Most species have two or more generations eachyear.

DAMAGE


11/28

P a g e | 11

Leafhopper feeding causes leaves to appear stippled, pale, or brown, and shoots may curl and die. Certainspecies secrete honeydew on which foliage-blackening sooty mold grows. Foliage can distort, discolor, andsometimes die. Some species vector pathogens. The aster leafhopper and other species vector the asteryellows phytoplasma, which infects many flower crops.MANAGEMENT

Because of their mobility, leafhoppers are difficult to control. Fortunately, control is rarely needed.Remove alternate hosts to reduce populations. Insecticidal soap or other insecticides applied whennymphs are small may be used if necessary to reduce populations but will not reduce virustransmission significantly. For heavy infestation use BIFEN 0.50 ml in 1 liter water. Spray every 15days. The effect will last for 6 months

LEAFMINERSLeafminer Pupua Leafminer Larva Leafminer Nymphs Leafminer Mines

Leafminers attack many different flower hosts, including aster, begonia, dahlia, impatiens, lily, marigold,petunia, and verbena. Adultare small, active, black and yellow flies. The most important species are theserpentine leafminer and the pea leafminer. Larvae are yellow cylindrical maggots.IDENTIFICATIONThe adult is a small, shiny black, clear-winged fly about 2.2 to 2.7 mm long. Head entirely black;mesonotum shining black; pleura and legs entirely black; squamae and fringe silvery white; halteresvariegated, primarily white, but knob with a conspicuous black area above; wing length about 2.2 to 2.7mm. Larvae are yellowish white, about 3 mm long, and make blotch-like tunnels within leaves where theselarvae are readily visible as they feed.LIFE CYCLE

In warm weather, leafminers may be more active. The life cycle is only 2 weeks long. Eggs are inserted intoleaves and larvae feed between leaf surfaces, creating a "mine." At high population levels, entire leavesmay be covered with mines. Mature larvae leave the mines, dropping to the ground to pupate. There canbe five to ten generations per year. Development continues all year, the population moving from one host toanother as new host plants become available each season.


12/28

P a g e | 12

DAMAGEAdult female leafminers puncture leaves and sometimes petals to feed on exuding sap. These punctureseventually turn white, giving foliage a stippled or speckled appearance. Larvae make a winding tunnel(mine) or sometimes a blotch between the lower and upper leaf surface. The mine becomes longer andwider as the larva grows. Mining usually has little impact on plant growth and rarely kills plants. Unusuallyheavy damage can slow plant growth and may cause infested leaves to drop.MANAGEMENTProvide proper care, especially irrigation to keep plants vigorous. Clip off and remove older infested leaves.Plant resistant species or varieties. Leafminers are often kept under good control by natural parasites.

Insecticides are not very effective for leafminer control. For heavy infestation spray 1 ml Cyphermithrinin 1 liter water or Biflex 0.50 ml in in liter water every 15 days till eradicated.

MEALYBUGS


13/28

P a g e | 13

Mealybug Eggs Mealybug Nymphs Mealybug Adult Mealybug Danmage

Most adult female mealybugs are wingless, soft-bodied, grayish insects about 0.05 to 0.2 inch long. Theyare usually elongate and segmented, and may have wax filaments radiating from the body, especially at thetail. Most females can move slowly and are covered with whitish, mealy or cottony wax. There are severaldifferent speciesIDENTIFICATIONThe ground mealybug is white and 2.4 to 3.9 millimeters long. It resembles a springtail, but moves muchmore slowly and cannot jump. The ground mealybug has slender waxy filaments that form a sort of nettingover some individuals. The ground mealybug also secretes a small amount of wax, which can give the soila somewhat bluish appearance when the mealybugs are abundant. Pritchards mealybug is snow white and

1.6 to 2.1 millimeters long and oval. It has small to non-existent eyes.LIFE CYCLEMost female mealybugs lay tiny yellow eggs intermixed with white wax in a mass called an ovisac.Mealybug nymphs are oblong, whitish, yellowish, or reddish and may or may not be covered with waxyfilaments. Most species feed on branches, twigs, or leaves. Depending on the species, host, and climate,they may overwinter only as eggs or as females, or as all stages. Most mealybugs have severalgenerations a year.

DAMAGE

Mealybugs tend to congregate in large numbers, forming white, cottony masses on plants. High populationsslow plant growth and cause premature leaf or fruit drop and twig dieback. Honeydew production and blacksooty mold are the primary damage caused by most mealybugs.MANAGEMENT


14/28

P a g e | 14

Provide proper cultural control so that plants are vigorous and can tolerate moderate mealybug feedingwithout being damaged. Naturally occurring predators and parasites provide good c ontrol of manymealybug species. Chemical control using systemic insecticides like Acephate (1 ml in 1 liter water)or Biflex (0.50 ml in 1 liter water) to be sprayed on the leaves, stem and the soil.

NEMATODES

Nematodes Nematodes Damge (LeftOnion Right Bulb) Nematode Root Damage Nematode LeafDamage Above Ground

Nematodes are microscopic, eel-like roundworms. The most troublesome species in the garden are thosethat live and feed within plant roots most of their lives and those that live freely in the soil and feed on plant

roots.Although there are many different species of root-feeding nematodes, the most damaging ones to gardensare the root knot nematodes. Root knot nematodes attack a wide range of plants, including many commonvegetables, fruit trees, and ornamentals. They are difficult to control, and they can spread easily fromgarden to garden in soil on tools and boots or on infested plants.IDENTIFICATION

Since you can not see nematode damage directly (without using a shovel!), you need to rely on visible

symptoms including wilting during the warmest period of the day, chlorosis, stunted growth, and general

lack of vigor. Ornamentals may have branch tip dieback and lose their leaves earlier than normal. And if

you have a large enough area, you may also note that damage is uneven, with affected plants among

healthy ones due to uneven distribution of nematodes.

In general, nematodes don't kill plants (they wouldn't have survived as long as they have if they did). But

they reduce the vigor of the plant and make it more likely to be harmed by other factors. And because the

symptoms are the same ones you see for "traditional" problems, a good rule of thumb is to analyze general

factors such as irrigation, nutrients, and visible symptoms of disease before suspecting nematodes (unless

you know there's a history of nematodes in your soil.LIFE CYCLEPlant-feeding nematodes go through 6 stagesan egg stage, 4 immature stages, and an adult stage.

Many species can develop from egg to egg-laying adult in as little as 21 to 28 days during warm summermonths. Immature stages and adult males are long, slender worms. Mature adult females of some speciessuch as root knot nematode change to a swollen, pearlike shape, whereas females of other species suchas lesion nematode remain slender worms. Nematodes are too small to be seen without a microscope.


15/28

P a g e | 15

DAMAGERoot knot nematodes usually cause distinctive swellings, called galls, on the roots of affected plants.Infestations of these nematodes are fairly easy to recognize; dig up a few plants with symptoms (seebelow), wash or gently tap the soil from the roots, and examine the roots for galls. The nematodes feed anddevelop within the galls, which can grow as large as 1 inch in diameter on some plants but usually aremuch smaller.

The formation of these galls damages the water- and nutrient-conducting abilities of the roots. Galls cancrack or split open, especially on the roots of vegetable plants, allowing the entry of soil-borne, disease-causing microorganisms. Root knot nematode galls are true swellings and cant be rubbed off the roots ascan the beneficial, nitrogen-fixing nodules on the roots of legumes. Root knot nematodes can feed on theroots of grasses and certain legumes without causing galling.

Aboveground symptoms of a root knot nematode infestation include wilting during the hottest part of theday even with adequate soil moisture, loss of vigor, yellowing leaves, and other symptoms similar to a lackof water or nutrients. Infested vegetable plants grow more slowly than neighboring, healthy plants,beginning in early to midseason. Plants produce fewer and smaller leaves and fruits, and ones heavilyinfested early in the season can die.

Although nematodes can kill annual plants, they rarely kill woody plants. Nematode injury to woody plants

usually is less obvious and often more difficult to diagnose. Infested fruit and nut trees can have reducedgrowth and yields. Woody landscape plants that are heavily infested can have reduced growth and branchtip dieback and can defoliate earlier than normal.MANAGEMENTManagement of nematodes is difficult. The most reliable practices are preventive, including sanitation andchoice of plant varieties. You can reduce existing infestations through fallowing, crop rotation, and soilsolarization. However, these methods reduce nematodes primarily in the top foot or so of the soil, so theyare effective only for about a year. They are suitable primarily for annual plants or to help young woody


16/28

P a g e | 16

plants establish. Once nematodes infest an area or crop, try to minimize damage by adjusting plantingdates to cooler times of the season when nematodes are less active. Try to provide optimal conditions forplant growth including sufficient irrigation and soil amendments to make plants more tolerant to nematodeinfestation. Chemical treatment is carried out by applying 0.50 ml of Biflex in 1 liter of water in thesoil after digging it. This lasts for 6 months.

SCALEScale Eggs Scale Adult Scale Colony Scale Damage OrangeLeaf Curl

Scale insects can be serious pests on trees, shrubs, and other perennials. The impact of infestationsdepends on the scale species, the plant species and cultivar, environmental factors, and natural enemies.Populations of some scales can increase dramatically within a few months, such as when honeydew-

seeking ants or dusty conditions interfere with scale natural enemies. Plants are not harmed by a fewscales, and even high populations of certain species apparently do not damage plants. Soft scales andsome other species excrete honeydew, a sweet, sticky liquid produced by insects that ingest largequantities of plant sap. Sticky honeydew and the blackish sooty mold growing on honeydew can botherpeople even when scale populations are not harming plants.IDENTIFICATIONScales are unusual looking and many people do not at first recognize them as insects. Adult female scalesand most immatures (nymphs) are immobile, wingless, and lack a separate head or other recognizablebody parts. Immature scales and adult females have a characteristic round or oval to elongate andflattened or humped appearance. Immature males are often a different color and shape than females,especially in later nymphal stages (instars). Adult male scales are tiny, delicate insects with one pair of

wings. Adult males are rarely seen, do not feed, and live only a few hours.LIFE CYCLEFemales of many scale species reproduce without mating (there are no males). At maturity, adult femalesproduce eggs that are usually hidden under her body or cover. Eggs hatch into tiny crawlers (mobile first -instar nymphs), which are yellow to orangish in most species. Crawlers walk over the plant surface, areblown by wind to other plants, or can be inadvertently moved by people or birds. They settle down andbegin feeding within a day or two after emergence.Settled nymphs may spend their entire life in the same spot without moving as they mature into adults.Nymphs of other species can move slowly but rarely do, such as when species that feed on deciduoushosts move from foliage to bark in the fall before leaves drop. For species with multiple generations, allscale life stages may be present throughout the year in areas with mild winters.

Armored Scales. Most armored scales have several generations a year. Armored scales overwinterprimarily as first-instar nymphs and adult females. Except for crawlers and adult males, armored scalesspend their entire life feeding at the same spot. Settled armored scales lose their legs, molt, and form theircharacteristic covers, which they gradually enlarge as they grow.Soft Scales. Most soft scales have one generation each year and overwinter as second-instar nymphs.The multi-generational brown soft scale is an important exception Brown soft scale females and nymphs ofvarious size can be present throughout the year. Most immature soft scales retain their barely visible legs


17/28

P a g e | 17

and antennae after settling and are able to move, although slowly. At maturity, females of certain softscales, the woolly sac scales (Margarodidae), and some other species produce distinct external cottony orwax-covered egg masses.

DAMAGEWhen plants are heavily infested with scales, leaves may look wilted, turn yellow, and drop prematurely.Scales sometimes curl leaves or cause deformed blemishes or discolored halos in fruit, leaves, or twigs.Bark infested with armored scales may crack and exude gum. Certain armored scales also feed on fruit, butthis damage is often just aesthetic. Soft scales infest leaves and twigs but rarely feed on fruit. A majorconcern with soft scales is their excretion of abundant honeydew, which contaminates fruit, leaves, andsurfaces beneath plants. Honeydew encourages the growth of black sooty mold and attracts ants, which inturn protect scales from natural enemies.

MANAGEMENTScales are often well controlled by beneficial predators and parasites, except when these natural enemiesare disrupted by ants, dust, or application of persistent broad-spectrum insecticides. Preserving(conserving) the populations of parasites and predators (such as by controlling pest-tending ants) may beenough to bring about gradual control of scales as natural enemies become more abundant. If scalesbecome too numerous, a well-timed and thorough spray using horticultural (narrow-range) oil applied eitherduring the dormant season or soon after scale crawlers are active in late winter to early summer shouldprovide good control. Complete spray coverage of infested plants (such as the underside of leaves) isneeded to obtain good control. Thorough spray coverage is especially critical when treating armored scalesand oak pit scales, as these scales are generally less susceptible to pesticides than soft scales.In case of severe infetstaion Chemical Control should be applied. Application of 0.50 ml Biflex orImidacloprid in 1 liter water is very effective and lasts for 6 months. This can be used as a foliarspray or as a soil application.


18/28

P a g e | 18

THRIPSThrips Eggs Thrips Larva Thrips Nymphs Thrips Rose Bud

Damage

Thrips, are tiny, slender insects with fringed wings. They feed by puncturing their host and sucking out thecell contents. Certain thrips species are beneficial predators that feed only on mites and other insects.Beneficial species include black hunter thrips and the sixspotted thrips. Pest species (often in the familyThripidae) are plant feeders that scar leaf, flower, or fruit surfaces or distort plant parts. Other species ofthrips feed on fungal spores and pollen and are innocuous.IDENTIFICATIONMost adult thrips are slender, minute (less than 1/20 inch long), and have long fringes on the margins ofboth pairs of their long, narrow wings. Immatures (called larvae or nymphs) are similarly shaped with a

long, narrow abdomen but lack wings. Most thrips range in color from translucent white or yellowish to darkbrown or blackish, depending on the species and life stage. A few species are more brightly colored, suchas the distinctive reddish orange abdomen of larvae of the predatory thrips.

In many species, thrips feed within buds and furled leaves or in other enclosed parts of the plant. Theirdamage is often observed before the thrips are seen. Discolored or distorted plant tissue or black specks offeces around stippled leaf surfaces are clues that thrips are or were present. However, some abioticdisorders, pathogens, and certain other invertebrates can cause damage resembling that of thrips. Forexample, lace bugs, plant bugs, and mites also stipple foliage, and lace bugs and certain plant bugsproduce dark, watery fecal specks. Look carefully for the insects themselves to be certain that pest thripsare present and the cause of damage before taking control action.

Thrips are poor fliers but can readily spread long distances by floating with the wind or being transported oninfested plants.LIFE CYCLEThe thrips life cycle includes the egg, two actively feeding larval (nymphal) stages, nonfeeding prepupal(propupal) and pupal stages, and the adult. Thrips have a metamorphosis that is intermediate betweencomplete and gradual. Last-instar larvae change greatly in appearance, and they are often called pupaeeven though thrips do not have a true pupal stage.Thrips eggs are elongate, cylindrical to kidney-shaped, and relatively large in relation to the female.Females of most plant-feeding species insert their tiny eggs into plants, commonly into leaves or budswhere larvae feed. The pale prepupae and pupae of most species drop to the soil or leaf litter or lodgewithin plant crevices. Greenhouse thrips pupate openly on lower leaf surfaces while pupae (and eggs) of

some gall-making species, such as Cuban laurel thrips, occur on leaf surfaces but are enclosed withindistorted plant tissue. Thrips have several generations (up to eight or more) a year. The life cycle from eggto adult may be completed in as short a time as 2 weeks when the weather is warm.


19/28

P a g e | 19

DAMAGE

Thrips prefer to feed in rapidly growing tissue. Feeding by thrips typically causes tiny scars on leaves andfruit, called stippling, and can stunt growth. Damaged leaves may become papery and distorted. Infestedterminals may discolor, become rolled, and drop leaves prematurely. Petals may exhibit color break,

which is pale or dark discoloring of petal tissue that was killed by thrips feeding before buds opened. Thripscause silvery to brownish, scabby scarring on the avocado and citrus fruit surface, but this cosmeticdamage does not harm the internal fruit quality. Feces may remain on leaves or fruit long after thrips haveleft. Where thrips lay eggs on grapes, dark scars surrounded by lighter halos may be found on the fruit.Thrips feeding on raspberries, apples, and nectarines can deform or scar developing fruit; sugar pea podsmay be scarred or deformed. Citrus thrips feeding severely distorts blueberry shoot tips and foliage,reducing fruit yield.In comparison with woody shrubs and trees in landscapes, herbaceous ornamentals and certain fruit andvegetable crops are generally more susceptible to serious injury from thrips feeding and thrips -vectoredviruses, especially when plants are young. Thrips feeding on woody plants can damage fruit and verynoticeably affect plants cosmetic appearance. But thrips rarely kill or threaten the survival of woody plants

unless the thrips populations are very high and cause serious feeding damage resulting in premature leafdrop or stem dieback.MANAGEMENTHealthy woody plants usually tolerate thrips damage; however, high infestations on certain herbaceousornamentals and developing fruits or vegetables may justify control. If control is necessary, use anintegrated program of control strategies that combines the use of good cultural practices and conservationof natural enemies with the use of least-toxic insecticides, such as narrow-range oils. In case of heavyinfestation uses of chemical insecticides become necessary. Spray CPP, Cypermithrin or Acephate 1 ml


20/28

P a g e | 20

in 1 liter water every 15 days till eradicated. Use of Biflerx or Imidacloprid 0.50 ml in in liter waterwill last for 6 months.STINK BUGSStink Bug Laying Eggs Stink Bug Nymphs Stink Bug Adult Brown Stink Bug Adult Green

The Stink Bug is also known as a shield bug because of the shield-like shape of its body. It also gets itsname from the pungent odor it emits when squashed, jostled, cornered, scared or injured. In large groups,stink bugs are considered agricultural pests because they suck juices from their host plants and causedamage to crops.

The four species of stink bugs are considered to be beneficial instead of pests:

The Anchor Bug preys upon the Mexican bean beetle, Japanese beetle and other insects; the Two SpottedStink Bug preys upon Colorado beetle larvae; the Spined Soldier bug feeds on caterpillars and other slowmoving arthropods; the Arboreal Stink Bug patrols tree trunks for ants and insects.IDENTIFICATIONTrue Stinkbugs usually have thickened forewings with membranous tips. When they rest, the dissimilarparts of their folded wings overlap. Most stink bugs can be recognised by the characteristic triangle or X-shape on the back formed by their folded wings. True bugs have sucking mouthparts, which on plant-feeding species point downward, perpendicular to the plane of the insect's bodyLIFE CYCLEAdult Brown Stink Bugs mate in early spring and females lay a mass of eggs weekly under the leaves ofthe host plant. She can lay up to 400 eggs in her lifetime. Eggs are light yellow to yellowish red. Nymphs

are tick-like in appearance. They go through five nymphal instars before becoming adults and have redeyes and an abdomen that changes color during each of the instars.

Stink bugs hibernate during cold winter months and will emerge in the spring as temperatures rise. Adultsmate in the spring and females will lay eggs on plants. These eggs will be laid in groups and are not plantspecific.Young will go through 5 stages to reach adulthood and this will occur in about three months.


21/28

P a g e | 21

DAMAGEAs a pest, the Brown Stink Bug will attack apples, cherries, raspberries, peaches, figs, mulberries, citrusfruits and persimmons. Feeding on fruit trees causes "cat facing" which will damage the fruit. They havealso been found on ornamental plants, weeds, soybeans and green beans. The Brown Stink Bug will overwinter in homes entering through small openings in windows and door frames, under roof shingles, in crawlspaces and attics.MANAGEMENTChemical control spray Cypermithrin or Deltamethrin, 1 ml in 1 l iter water.

Experts say that the best stink bug control is prevention. Those worried about stink bug infestation can startby keeping the yard clean of any unnecessary plants. Weeds and overgrown bushes should be taken careso stink bugs will not have any place to feed or lay eggs.To prevent a stink bug invasion, all holes, cracks and crevices around house should be tightly sealed withcalk. The bugs are also known for using the attic and air conditioner to get inside the house. During fall,before they migrate inside the house, it is best to treat the exterior and attic of the house with multi-purposeinsecticide such as Biflex 0.50 ml in 1 liter water.. Window a/c unit should be removed and the windowsseal properly.Two popular pest control options: Permethrin is a pest repellant that paralyzes the nervous system of manyinsects and kills all stages of the insects growth. Imdeachlorprid 0.50 ml in 1 liter water. This will keep the

stinkbugs away for 6 months.


22/28

P a g e | 22

WEEVILS

Weevil Eggs Weevil Pupa (above) &Larva Below

Weevil Adult Weevil Citrus Damage

Weevils feed on many flower hosts, including aster, begonia, carnation, chrysanthemum, dahlia, geranium,impatiens, lily, primrose, and vinca. Weevils are inconspicuous. Larvae are whitish or green grubs and livein soil. Adults are dull gray, blackish, or brown and feed at night, hiding in litter during the day. The head ofadult weevils is elongated into a snout and their antennae are elbowed and clubbed. Adults do not fly.IDENTIFICATIONThere are more than 1,000 species of weevils or snout beetles in California. The most common pest weevilspecies in California is the black vine weevil,.Other important species include the cribrate weevil, , fullerrose beetle, obscure root weevil, strawberry root weevil, vegetable weevil, and the woods weevil.The adultweevils have a snout and are about one-fourth inch long. They vary from reddish-brown to gray to almostblack in color. A distinguishing feature is the presence of two spurs on the front femur of each leg. Theadult weevil is usually dull in color and herbivorous, characterized by a prolongation of the anterior part ofthe head into a rostrum (a beaklike extension). The apex of the rostrum contains the biting mouthparts, andtwo clubbed antennae are attached in depressions at each side. The oval body is covered with a rough,hard integument, and a single median suture traverses the lower part of the head. Weevils exhibit completemetamorphosis; the larvae are white, semicircular, fleshy grubs with vestigial legs, strong jaws, andrudimentary eyes; they feed entirely on plant life, causing much damage to crops. The adults usuallyhibernate for most of the winter.LIFE CYCLEAdult weevils spend the winter in ground trash near old cotton fields. Each female can lay up to 200 eggs(laying each egg in a separate cotton square or boll). The entire life cycle of egg to adult can be completedin 3 weeks or less. There are multiple (5 or more) generations per year.Females can produce eggs without mating, commonly laying them on or into soil near host plants. Thefemale adults must feed for about a month before laying eggs. The larvae develop in soil through 6 instarsover a period of 2 to 8 months. They are whitish grubs with a brown head and commonly have a C-shapedposture.Black vine weevil overwinters primarily as a late-instar larva. A few individuals of this and other species canoverwinter as adults. Weevils overwintering as late instars form pupae in spring. Adults emerge from thesoil about 2 weeks after pupation and begin feeding during the night.DAMAGEAdult weevils chew foliage, causing characteristic notching on leaf edges. The serious damage is caused

by larvae. Young larvae chew the outer surface of young roots. More mature larvae chew older roots andbasal stems, girdling plants near the soil surface and causing decline in mature plants and death in youngplants.MANAGEMENTDestroy adults to prevent more serious damage. Grow species or cultivars that are less susceptible toweevil damage, and avoid replanting susceptible crops at infested sites. Grow older plants that are morelikely to be infested away from younger plants susceptible to weevils. Provide cultural care to keep plantsvigorous and better able to tolerate damage. Check roots before planting to make sure they are free from


23/28

P a g e | 23

larvae. Trim branches that provide a bridge to other plants or the ground and apply a 6-inch band of stickymaterial to trunks to prevent flightless beetles from feeding on foliage. Application of Cypermithrin orDeltamithrin or CPP 1ml in 1liter water spray applied to leaves can control adults.WHITEFLIESWhite Flies Eggs White Flies Pupa White Flies Larva White Flies Colony

The silverleaf whitefly is slightly smaller (about 0.96 mm in the female and 0.82 mm in the male) andslightly yellower than most other whitefly pests of flowers. The head is broad at the antennae and narrowtowards the mouth parts. The wings are held roof-like at about a 45 angle, whereas other whitefliesusually hold the wings nearly flat over the body. Hence, the silverleaf whitefly appears more slender thanother common whiteflies.Whiteflies are tiny, sap-sucking insects that are frequently abundant in vegetable and ornamental plantings.

They excrete sticky honeydew and cause yellowing or death of leaves. Outbreaks often occur when thenatural biological control is disrupted. Management is difficult.IDENTIFICATIONWhiteflies usually occur in groups on the undersides of leaves. They derive their name from the mealy,white wax covering the adults wings and body. Adults are tiny insects with yellowish bodies and whitishwings. Although adults of some species have distinctive wing markings, many species are most readilydistinguished in the last nymphal (immature) stage, which is wingless.LIFE CYCLEwhiteflies that were undoubtedly silverleaf whiteflies. Developmental times from egg deposition to adultemergence appears to be primarily controlled by temperature, humidity, and host plant. These times willvary from 16 to 38 days depending on these factors. The number of eggs laid by each female over her

lifetime varies considerably, but appears to be around 80 to 100. Crawlers hatch from the eggs and crawlabout until they insert threadlike mouthparts into the underside of the leaf to feed. They tuck their legs andantennae underneath and settle down closely to the leaf surface.Crawlers molt into scale like nymphs that also suck out sap. Nymphs molt a second and third time. Thefourth stage eventually becomes a non-feeding pupa. The adult whitefly develops within the pupa. Adultsemerge from the pupa through a T-shaped slit about a month from the time the egg was laid. Females liveabout two weeks

The eggs are inserted on end in the undersides of new leaves. The eggs are whitish to light beige with theapex tending to be slightly darker.Nymphs: The nymphal stages appear glassy to opaque yellowish and may or may not have dorsal spines,

depending on leaf characteristics. The body is flattened and scale-like with the margin relatively near theleaf surface. There is not a marginal palisade of waxy spines.Pupae: The pupa or fourth nymphal instar will be somewhat darker beigeish-yellow and opaque and 0.6 to0.8 mm long. Pupae are relatively more plump compared to previous nymphal stages. The apex of anteriorand caudal spiracular furrows have smalls amount of white wax deposits. The caudal setae are prominent,and the caudal end is somewhat acute. Dorsal spines are present when the host leaf is hairy and absentwhen the host leaf is smooth.


24/28

P a g e | 24

DAMAGEDirect damage is caused by the removal of sap, and indirect damage as a disease vector. The silverleafwhitefly is a vector for several important virus diseases of lettuce and melons in the southwestern UnitedStates. Both the adult and nymphal stages contribute to direct damage. Chlorotic spots sometimes appearat the feeding sites on leaves, and heavy infestations cause leaves of cucurbits and stems of poinsettias toblanch and wilt. The excretion of honeydew and the subsequent development of sooty mold fungi also

reduces the appearance, photosynthesis, and other physiological functions of the plant. Even though thesilverleaf whitefly is considered an economic pest, economic thresholds have not been generated for thispest on ornamental plants.Whiteflies suck phloem sap. Large populations can cause leaves to turn yellow, appear dry, or fall offplants. Like aphids, whiteflies excrete honeydew, so leaves may be sticky or covered with black sooty mold.The honeydew attracts ants, which interfere with the activities of natural enemies that may control whitefliesand other pests.Feeding by the immature silverleaf whitefly can cause plant distortion, discoloration, or silvering of leavesand may cause serious losses in some vegetable crops. Some whiteflies transmit viruses to certainvegetable crops. With the notable exception of the citrus whitefly, whiteflies are not normally a problem infruit trees, but several whiteflies can be problems on ornamental trees . Low levels of whiteflies are not

usually damaging. Adults by themselves will not cause significant damage unless they are transmitting aplant pathogen. Generally, plant losses do not occur unless there is a significant population of whiteflynymphs.MANAGEMENTControl of silverleaf whiteflies is difficult because the eggs and older immature forms are resistant to manyaerosol and insecticide sprays (in addition, the adults are extremely resistant to dry pesticide residue). Forgood control, the pesticide mixture must be directed to the lower leaf surface where all stages of thewhiteflies naturally occur. One must make regular applications of pesticides to control crawlers and second


25/28

P a g e | 25

stage nymphs until the last of a whole generation of immature whiteflies has hatched. However, some ofthe pyrethroid pesticides are somewhat more effective and need not be applied as often.The best strategy is to prevent problems from developing in your garden to the extent possible. In manysituations, natural enemies will provide adequate control of whiteflies; outbreaks may occur if naturalenemies that provide biological control of whiteflies are disrupted by insecticide applications, dusty

conditions, or interference by ants. Avoid or remove plants that repeatedly host high populations ofwhiteflies. In gardens, whitefly populations in the early stages of population development can be held downby a vigilant program of removing infested leaves, vacuuming adults, or hosing down (syringing) with watersprays. Aluminum foil or reflective mulches can repel whiteflies from vegetable gardens and sticky trapscan be used to monitor or, at high levels, reduce whitefly numbers. If you choose to use insecticides,insecticidal soaps or oils such as neem oil may reduce but not eliminate populations. Chemical insecticideslike Biflex and Imidachlorprid spray 0.50 ml in 1 liter water will control it for 6 months.POWDERY MILDEWPowdery Mildew RoseDamage

Powdery Mildew SquashDamage

Powdery MildewOrnimental Damage

Powdery MildewDamage

Powdery mildew is a common disease on many types of plants and is prevalent under the diverseconditions found in many areas India. Different powdery mildew fungi cause disease on different plants.These fungi tend to infect either plants in the same family or only one species of plant.IDENTIFICATION ANDDAMAGE

You can recognize this disease by the white, powdery spore growth that forms on leaf surfaces and shootsand sometimes on flowers and fruits. Powdery mildews may infect new or old foliage. This disease can beserious on woody species such as rose, crape myrtle, and sycamore where it attacks new growth includingbuds, shoots, flowers, and leaves. New growth may be dwarfed, distorted, and covered with a white,powdery growth. Infected leaves generally free moisture.

Wind carries powdery mildew spores to new hosts. Although relative humidity requirements for germinationvary, all powdery mildew species can germinate and infect in the absence of free water. In fact, water onplant surfaces for extended periods inhibits germination and kills the spores of most powdery mildew fungi.Moderate temperatures of 60 to 80F and shady conditions generally are the most favorable for powderymildew development. Powdery mildew spores and mycelium are sensitive to extreme heat and sunlight,

and leaf temperatures above 95F may kill the fungus. die and drop from the plant earlier than healthyleaves.LIFE CYCLEAll powdery mildew fungi require living plant tissue to grow. On perennial hosts such as roses, powderymildew survives from one season to the next as vegetative strands in buds or as spherical fruiting bodies,called chasmothecia, on the bark of branches and stems.Most powdery mildew fungi grow as thin layers of mycelium on the surface of the affected plant parts.Spores, which you can see with a hand lens, are part of the white, powdery appearance of this fungi and
http://www.ipm.ucdavis.edu/PMG/P/D-SF-PCLA-FU.005.htmlhttp://www.ipm.ucdavis.edu/PMG/P/D-SF-PCLA-FU.005.html


26/28

P a g e | 26

are produced in chains on upper or lower leaf surfaces or on flowers, fruits, or herbaceous stems. Incontrast, downy mildew, another fungal disease that produces visible powdery growth, has spores thatgrow on branched stalks and look like tiny trees.

MANAGEMENTThe best method of control is prevention. Avoiding the most susceptible cultivars, placing plants in full sun,and following good cultural practices will adequately control powdery mildew in many situations. Someornamentals do require protection with fungicide sprays if mildew conditions are more favorable, especiallysusceptible varieties of rose.Fungicide ApplicationsIn some situations, especially when growing roses, you may need to use fungicides, which function asprotectants, eradicants, or both. A protectant fungicide prevents new infections from occurring, whereas aneradicant can kill an existing infection. Apply protectant fungicides to highly susceptible plants before thedisease appears. Use eradicants at the earliest signs of the disease. Once mildew growth is extensive,controlling the situation with any fungicide becomes more difficult.Fungicides. Several least-toxic fungicides are available, including horticultural oils, neem oil, jojoba oil,sulfur, potassium bicarbonate, and the biological fungicide Serenade. With the exception of the oils, thesematerials are primarily preventive, although potassium bicarbonate has some eradicant activity. Oils workbest as eradicants but also have some protectant activity.Oils. To eradicate mild to heavy powdery mildew infections, use a horticultural oil such as JMS Stylet Oil,Saf-T-Side Spray Oil, Sunspray Ultra-Fine Spray Oil, or one of the plant-based oils such as neem oil or


27/28

P a g e | 27

jojoba oil. Be careful, however, never to apply an oil spray within 2 weeks of a sulfur spray, or it may injureplants. Also, you never should apply oils when temperatures are above 90F or to water-stressed plants.Some plants may be more sensitive than others, and the interval required between sulfur and oil spraysmay need to be even longer.

Sulfur products have been used to manage powdery mildew for centuries but are effective only whenapplied before the disease appears. The best sulfur products to use for powdery mildew control in gardensare wettable sulfurs that are specially formulated with surfactants similar to those in dishwashing detergent(e.g., Safer Garden Fungicide). However, you shouldnt use dishwashing detergent with sulfur. Additionally,sulfur can damage some ornamental cultivars. To avoid injuring any plant, do not apply sul fur when thetemperature is near or higher than 90F, and do not apply it within 2 weeks of an oil spray. Other sulfurproducts, such as liquid lime sulfur or sulfur dust, are much more difficult to use, irritate skin and eyes, andare limited in the types plants you safely can use them on.

Biological fungicides are commercially available beneficial microorganisms formulated into a product that,when sprayed on the plant, destroys fungal pathogens. These products have some effect in killing the

powdery mildew organism but are not as effective as the oils or sulfur in controlling it.How to Use. Apply protectant fungicides to susceptible plants before or in the earliest stages of diseasedevelopment. Once mildew growth is mild to moderate, it generally is too late for effective control withprotectant fungicides. These are effective only on contact, so applications must thoroughly cover allsusceptible plant parts. As plants grow and produce new tissue, additional applications may be necessaryat 7- to 10-day intervals as long as conditions favor disease growth.

If mild to moderate powdery mildew is present, you can use horticultural and plant-based oils such as neemor jojoba oil.DOWNEY MILDEW

Downey MildewDamage Downey Mildew SpotsDamage Downey Mildew BelowLeaf Damage Powdery MildewDamage

Downy mildews have gained a strong foothold in the horticultural industry. They are currentlycausing serious losses in many floricultural crops including rose, cut and bedding plant, pansy, viola,alyssum, salvia, and rosemary. Despite the sound-alike name of the powdery mildews, the two groups offungi have little in common, attacking different plants, under very different conditions. Downy mildew

diseases thrive when the weather conditions are wet and cool. Most of the fungi that cause these diseasesare host specific, attacking only one kind of plant. The fungus that causes downy mildew on roses cannotcause the disease on snapdragons and visa versa. The fungus that causes downy mildew on violas causesthe same disease on pansies as the two plants are very closely related. Some of the downy mildews aremore aggressive than others. For example, downy mildew on snapdragons appears to spread much fasterand cause more serious losses quickly than the downy mildew on pansy and viola. Since the fungus growswithin the plant tissues and not on the surface it can escapenotice until the conditions are ideal for sporulation. At this time, the fruiting structures of the fungus emerge


28/28

P a g e | 28

from the undersides of leaves and create the grayish-colored, downy coating. On some plants, this may bethe first indication that they are infected with a downy mildew fungus. In other plants, distortion of newleaves, downward curling and overall stunting occur which can mimic aphid damage. In contrast, rosesdevelop reddish-black spots on leaves, petals, and stems, well in advance of sporulation.LIFE CYCLE

Some downy mildew diseases are known to start from contaminated seed (sunflowers) but most have notbeen proven to be seed-borne as yet (snapdragon). In addition, there are many weed hosts of certaindowny mildew fungi which attack cultivated crops and some epidemics start on weeds around theproduction area. Rose downy mildew sometimes starts on bare-rooted, apparently healthy stock. Rosecanes infected with the fungus may not be obvious and symptoms may appear only when environmentalconditions are ideal. Since exposure of spores to 80 F for 24 hours kills them, a heat treatment of canes,seeds or other propagation stock, might be effective. Killing the pathogen within the plant would be moredifficult and the temperatures needed might damage the plant as well.ENVIRONMENTAL CONCERNSDowny mildew is most severe when nights are cool and days are warmer with high relative humidities.Humidity management is sometimes possible and always desirable when growing plants in a greenhouse.

It is critical to keep the relative humidity below 85% to decrease sporulation on infected plants and stopgermination of spores on healthy plants.

This can be done in greenhouses by venting and raising the temperature at key times during the day,especially at sunset when the greenhouse air is warm and moisture laden and the outside air is cool anddrier. Venting followed by heating will fill the greenhouse with warmer, drier air. Fans can speed leaf dryingbut also spread downy mildew spores. Other methods (perhaps fungicides or removing infected plants)should be used in combination with fans to minimize disease spread. The optimal temperature fordevelopment of rose downy mildew is 64 F and snapdragon downy mildew develops best withtemperatures between 40 and 60 F. Temperature optima for other ornamental downy mildew fungi are notknown at this time. A few of those known for non-ornamental crops include: crucifers (45-60 F), lettuce (50-70 F), and soybean (50-80 F). Thus, although the temperatures are close, they are not identical and eachdisease must be studied to determine the optimal range for that spores on plants in the trash pile. Placeplants in plastic trash bags as they are collected from the growing area to keep spores from beingdislodged and spread in air currents.MANAGEMENTSanitation requirements for downy mildew diseases are stringent. Infected plant tissues such as leaves,stems and flowers may drop to the ground where the spores can remain viable for various periods of time.Remove all infected plants and discard well away from your production area. If you collect debris in a pileclose to production you may continue to experience new infections starting with formation of spores onplants in the trash pile. Place plants in plastic trash bags as they are collected from the growing area tokeep spores from being dislodged and spread in air currents.USE OF FUNGICIDES

The most important thing about using a fungicide for downy mildew control is to recognize therelationship between these fungi and other plant pathogens. The fungicides which are effective for watermolds have the best activity against the downy mildew fungi as well. Fungicides have been tested forcontrol of downy mildew on roses throughout the world. In general, dithiocarbamates (such as Dithane andsulfur dusts, and sometimes copper products have been recommended.

Garden Pests and Diseases Control

Documents

Transcript of Garden Pests and Diseases Control