Cabbage Integrated Pest Management : An Ecological Guide.

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Major Cabbage Insect PestsThe sad story of chemical control of DBMChemical control has been the major control tactic used in the past. Due to the many generationsthat DBM can produce in a season, it can also develop resistance to insecticides very quickly. Moreand more, insecticides became ineffective in controlling DBM. Some insecticides to which DBM hasdeveloped resistance include cypermethrin, deltamethrin, fenvalerate, diazinon, permethrin andphenthoate. For example, in Taiwan,DBM has developed resistance against33 out of the 34 available insecticides!It seems like the insect could developpesticide resistance more quickly thanthe chemical industry could developnew pesticides!Due to the ineffectiveness ofinsecticides, farmers began to spraymore often, at higher doses, with differentchemicals and with mixtures andcocktails of pesticides. The result?Higher costs for farmers to buy thepesticides, more health risks from applying sometimes very dangerous chemicals, more environmentalpollution and eventually more resistance of DBM against these pesticides. The big winner of thegame? DBM! Still a major pest in many regions. The other winners of the game? Other insects suchas armyworms and the cabbage webworm, once minor pests of cabbage, could become majorproblems because all natural enemies were destroyed.¤Points to remember about diamondback moth:1. Diamondback moth (DBM) is the most serious pest of tropical cabbage areas.2. Very effective biological control of DBM is possible through parasitoids.3. Parasitoid release should be part of a larger IPM programme, that includes farmer training.4. Pesticides are not effective for DBM control.5. Natural enemies are killed by pesticides.6. Bt is usually very effective for DBM control, but brands should be rotated (resistance!).Related exercises from CABI Bioscience/FAO manual:4-A.14-A.2.4-A.3.4-A.4.4-A.5.4-A.6.4-A.7.4-A.8.4-A.124-A.13Life cycle of caterpillar pestsDiamondback moth injury symptoms on cabbagePlant compensation studyAssessment of impact of ground-dwelling predatorsMeasuring the parasitism level of caterpillarsParasitisation on diamondback moth of cabbageEffect of parasitisation on feeding behavior of diamondback mothRainfall as mortality factorMixed cropping examples: tomato/beans and cabbage/mustardComparison of biological and chemical pesticides used in caterpillar control.81 Cabbage Ecological Guide - 2000
Major Cabbage Insect Pests5.2 Aphids - Brevicoryne brassicaeDescriptionCabbage aphids are a serious pest on most cruciferous crops including a wide range of cruciferousweeds.(from Stoll, 1987)The wingless aphids are up to about 2.5 mm long, grayish-green in color, with a dark head and blackstripes on the body. The aphid is covered with a grayish-white colored waxy powder, which is alsosecreted onto the surface of host plants.The winged aphids are slightly longer than the wingless ones and have a dark-colored head and body.The veins on the wings appear brown in color. The aphids have small syphons (looking like small antennae)at the back of their body. Syphons are a good way to recognize aphids.Colonies of these aphids are usually found on the undersides of cabbage leaves.Unlike other aphid pests of vegetables, the cabbage aphid is a one-host aphid : it remains on cruciferouscrops throughout its life.The aphids can reproduce asexually: that means that males and females do not have to mate in order toproduce young. One female gives birth directly to small nymphs. That means large numbers of aphidscan be produced in a very short time! Only in cool areas, eggs are produced after mating. The eggsoverwinter and young nymphs emerge when the temperature rises. All winged aphids are females. In thetropics, most unwinged aphids are probably also females. Most reproduction in the tropics will be asexualso males are not needed.Life cycleIn the cooler areas of its distribution, the cabbage aphid overwinters as small, shiny black-colored eggslaid particularly around leaf scars of stems of plants that remain in the field throughout the winter. Whenthe temperature rises, the aphids hatch and colonize the new emerging flowering stems or harvestedvegetable crops that have not been ploughed in. Then, winged aphids fly away to colonize new hostplants. They produce wingless aphids. These aphids produce more young aphids that form new colonies.They feed on the tender, actively growing shoots and leaves, often on the underside of leaves where theyare protected from the sun and rain. When aphid numbers outrun food supply, winged forms reappear andmigrate to nearby plants to renew the growth cycle. This happens regularly during the growing season.Warm, dry weather favors a rapid build-up of aphid colonies.Cabbage Ecological Guide - 200082
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Why this guide?About this guideThis
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Introduction1.4 Cabbage: a bit of h
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Cabbage Crop DevelopmentPresently t
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Cabbage Crop Development2.2 Suscept
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Major Agronomic Practices3MAJOR AGR
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Major Agronomic Practices3.2.3 Seed
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Major Agronomic PracticesUse protec
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Major Agronomic Practices3.4.2 Soil
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Major Agronomic Practicesthan 7, th
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Major Agronomic Practices3.4.7 Soil
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Major Agronomic PracticesSome of th
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Major Agronomic PracticeslllCreates
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Major Agronomic PracticesWhen a com
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Major Agronomic PracticesIn additio
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Page 75 and 76: Major Cabbage Insect Pests5MAJOR CA
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Major Natural Enemies of Cabbage In
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Disease Ecology7.1 Plant diseases a
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Disease Ecology7.3 How diseases spr
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Disease EcologyThe disease triangle
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Disease Ecologygrowth malformations
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Disease Ecology7.8 Control or manag
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Disease Ecologycontaminated seeds :
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Disease EcologyTrichoderma species
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Major Diseases of Cabbage8MAJORDISE
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Major Diseases of CabbageRole of en
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Major Diseases of CabbageOnce there
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Major Diseases of Cabbage· Practic
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Major Diseases of Cabbage¤Points t
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Major Diseases of Cabbagespores wit
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Major Diseases of Cabbage¤Points t
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Major Diseases of Cabbagebut does n
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Major Diseases of Cabbage8.7 Downy
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Major Diseases of Cabbage8.8 Black
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Major Diseases of CabbageNitrogen (
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Weed Management9WEEDMANAGEMENTSUMMA
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Weed ManagementBroadleaf weeds or g
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Weed Managementcompost or it may be
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Weed Management· Check details of
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Weed ManagementTherefore, to date,
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Rodent ManagementRats are a common
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Rodent Management10.4 Rat managemen
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Rodent Management10.4.4 Biological
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Key to Some Common Cabbage Insect P
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Literature and Internet Reference L
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PESTS & DISEASES COMMON TO CABBAGEP
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Plate 3Fig. 13 : Advanced symptoms
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deficiency symptoms ---------------
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chemical --------------------------
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Cabbage Integrated Pest Management : An Ecological Guide.

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