Cabbage Integrated Pest Management : An Ecological Guide.

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Major Diseases of CabbageNitrogen (N) deficiencyIn cabbage plants, symptoms are usually a purple glow on the leaves. Symptoms are located throughoutthe plant, although the older leaves usually show symptoms most clearly. When nitrogen deficiencyoccurs early in the growing season, the plants may stay small in size and head formation may bedistorted. In light, sandy soils, nitrogen deficiency can easily occur after heavy rainfall. The rain will washthe nitrogen out to deeper layer of the soil where it is inaccessible for the crop.Adding nitrogen (chemical fertilizer) is usually sufficient to overcome nitrogen deficiency for the shortterm. Adding organic material to the soil improves nutrient holding capacity of the soil and it therefore amore permanent solution.Nitrogen (N) excessToo much nitrogen leads to tall, weak plants. Plants basically grow “too fast” and become weak andtherefore more susceptible to diseases. Sometimes, no cabbage heads develop. In addition, too muchnitrogen may result in a high concentration of nitrate in the leaves which is detrimental for humanhealth L.Phosphorous (P) deficiencySymptoms of phosphorous deficiency are plants that stay small in size. Leaves are dark green to bluishgreen in color. Sometimes, a purple color at the undersides of the leaves can be seen. Symptoms arelocated throughout the plant. It is difficult to correct deficiency symptoms with additional fertilizer applicationonce the symptoms are there. Proper fertilization before the crop is transplanted and use of lots of (welldecomposed)organic material is the best prevention.Potassium (K) deficiencySymptoms of potassium deficiency are a bluish-green coloration followed by yellowing and scorching ofthe leaf margins, accompanied by poor heading. The symptoms are located mainly at the older leaves.Potassium deficiency symptoms are liable to occur on land recently broken up from grass, on light soils,on heavy soil with deficient drainage and in land heavily manured with nitrogenous materials.Boron deficiencyCabbage heads may be small and yellow. The stems of cabbage may be cracked and corky. Leaves maybecome dry and papery. Light soils are more susceptible to boron deficiency, especially in very dryperiods. Also, soils with high pH are more susceptible to boron deficiency.Boron can be added to soils separately but a soil test is advisable to ensure that boron levels are not toohigh.Magnesium (Mg) deficiencyThe symptoms of magnesium deficiency are pale marbled areas between the veins (chlorosis), sometimesaccompanied by a purple color of the leaves. The pale areas finally dry out into brown dead patches. Thesymptoms are located mainly at the older leaves.Growth and maturity may be greatly checked and the plants may become badly affected with diseaseslike downy mildew.171 Cabbage Ecological Guide - 2000
Major Diseases of CabbageDeficiency of magnesium may occur both on acid soils and on soils containing ample supplies of lime,especially where this has been added. It is most prevalent on light soils under conditions where themagnesium is readily leached away, like in wet seasons. The deficiency may become apparent afterseveral years of routine manuring with inorganic fertilizers.In acid soils, magnesium limestone may be applied to counteract the deficiency. Other magnesiumcontaining fertilizers like magnesium sulfate can also be used, preferably before the seedlings aretransplanted. The turning-in of green manures and the use of farmyard manure or compost also tend topreserve supplies of magnesium in the soil.List of related disease exercises from CABI Bioscience/FAO manual:3-A.1. Study of symptom development of leaf spots: classroom exercise3-A.2. Study of symptom development of leaf spots: field exercise3-A.3. Effect of infection of the seed bed3-A.4. Effect of the use of infected planting material3-A.5. Test effect of hot water seed treatment3.B.1. Seed drenching/coating to manage damping-off3-A.6., 3.B.2 and. 3.D.2. Use of subsoil to manage diseases in the nursery3-A.7., 3. B.3. and 3.D.4. Soil solarisation to manage diseases in the nursery3-A.8., 3. B.4. and 3.D.3. Steam sterilisation to manage diseases in the nursery3-D.5. Test effect of soil solarisation in the field3-A.9. Test effect of infected crop debris in the field3-E.4. Sanitation measures to manage cabbage soft rot3-A.10. and 3-E.2. Effect of rain on the spread of diseases3-A.11. and 3.E.1. Spread of diseases by farming tools3-A.12. and 3-E.5. Test different cultivars for resistance to diseases3-A.13. Pruning and plant compensation3-E.3. Pruning of infected shoots versus fungicide application3-A.14. Restricted fungicide use to manage leaf spots3-A.16. Study of spread of a fungal leaf spot3-D.1. Pot experiments to test whether root diseases are soil-borne3-D.6. Effect of liming on clubroot of cabbage3-F.9. Virus or nutrient deficiency?Cabbage Ecological Guide - 2000172
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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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Major Agronomic PracticesSome farme
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Major Agronomic PracticesEffects of
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Major Agronomic PracticesAn example
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Major Agronomic Practicesseed beds,
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Major Agronomic Practicesthis layer
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Major Agronomic PracticesPotting se
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Major Agronomic PracticesTransplant
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Major Agronomic Practices3.9 Water
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Major Agronomic PracticesHowever, w
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Major Agronomic PracticesSome examp
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Ecology of Insect Pests and Natural
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Major Cabbage Insect Pests5MAJOR CA
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Major Cabbage Insect PestsDiadegma
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Major Cabbage Insect PestsTrap crop
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Major Cabbage Insect PestsThe sad s
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Major Cabbage Insect PestsPlant dam
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Major Cabbage Insect PestsJ Free bi
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Major Cabbage Insect Pestsbeetles.
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Major Cabbage Insect Pestsinstars f
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Major Cabbage Insect Pests¤Points
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Major Cabbage Insect PestsSome NPV
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Major Cabbage Insect PestsAdults ar
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Major Cabbage Insect PestsThe adult
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Major Cabbage Insect PestsLarval de
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Major Cabbage Insect PestsLife cycl
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Major Cabbage Insect Pests5.10 Whit
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Major Cabbage Insect PestsParasitic
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Major Cabbage Insect PestsRelated e
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Major Natural Enemies of Cabbage In
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Page 142 and 143: Disease EcologyThe disease triangle
Page 144 and 145: Disease Ecologygrowth malformations
Page 146 and 147: Disease Ecology7.8 Control or manag
Page 148 and 149: Disease Ecologycontaminated seeds :
Page 150 and 151: Disease EcologyTrichoderma species
Page 152 and 153: Major Diseases of Cabbage8MAJORDISE
Page 154 and 155: Major Diseases of CabbageRole of en
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Page 168 and 169: Major Diseases of Cabbage8.7 Downy
Page 170 and 171: Major Diseases of Cabbage8.8 Black
Page 174 and 175: Weed Management9WEEDMANAGEMENTSUMMA
Page 176 and 177: Weed ManagementBroadleaf weeds or g
Page 178 and 179: Weed Managementcompost or it may be
Page 180 and 181: Weed Management· Check details of
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Page 184 and 185: Rodent ManagementRats are a common
Page 186 and 187: Rodent Management10.4 Rat managemen
Page 188 and 189: Rodent Management10.4.4 Biological
Page 190 and 191: Key to Some Common Cabbage Insect P
Page 192 and 193: Literature and Internet Reference L
Page 200 and 201: PESTS & DISEASES COMMON TO CABBAGEP
Page 202 and 203: Plate 3Fig. 13 : Advanced symptoms
Page 204 and 205: deficiency symptoms ---------------
Page 206: chemical --------------------------
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