Cabbage Integrated Pest Management : An Ecological Guide.

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Disease Ecology7.8 Control or management?It is important to realize that diseases require another way of thinking in order to have long-term control.Diseases must be managed, not controlled. But what is the difference and why is that important toknow?Management means a range of activities that support each other. Many or these activities should bedone before transplanting of the crop, some even before sowing the seeds. Disease management is along-term activity, sometimes it is a planning for several years. It is mainly focused on preventing thedisease from coming into a field. It also aims at keeping disease pressure low in case a disease ispresent. Management usually needs the cooperation of several farmers working together to reduce overalldiseases in an area.Control is a short-term activity, focused on killing a disease or stopping the spread of it. The trouble withdiseases is that you only see them when you see the symptoms. That means infection already occurredat least a few days before. It also means that plants that look healthy today, may have disease symptomstomorrow. Once a plant is infected, it is difficult to actually kill the pathogen. Especially when pathogenslive in the soil and attack plants through the root system, they can only be controlled by proper managementtechniques like crop rotation or cultural methods. And those kind of methods usually have to bedone before transplanting the crop!Spraying fungicides, a typical short-term activity, may be a control option but only for a limited number ofdiseases and usually only partially. So a combination with cultural practices like sanitation is essential!It should be noted that some fungicides can kill natural enemies, including predators and parasitoids(see box in section 4.9).In order to make a good disease management decision, you have to know a few basic things about thedisease. Things like: where does it come from, how does it spread? Knowing this will give you a clue howto manage it. Soil-borne diseases are managed different from wind-borne diseases!Diseases can never be completely eradicated -but populations can be reduced to low levels!But before talking about control, think about: how important is this disease, what damage does it do tomy overall yield at the end of the season? What would be the effect of this disease to the crop in the nextseason? A few leafspots here and there may not reduce your yield. At what growth stage does thedisease appear? What are the weather conditions, are they favorable for a quick spread of the leafspot?Yes, you may be able to temporarily stop the spread of those leafspots by applying fungicides. But whatare the costs of those fungicides? What are the negative side-effects of fungicides to the natural enemypopulation? How much extra income do you estimate you can win by a few spotless cabbages? That iswhat counts in the end!7.9 Disease management: where to start?Disease management starts with the identification of the problem. Once you have found the cause of theproblem, and it is a disease, the easiest way is to check if there are any resistant crop varieties available(see section 3.2). Also, if you know that the disease is giving a lot of problems in one season but not inanother, it may be worth considering not to grow the crop in the susceptible season. Not growing the cropat all for a few years (crop rotation) is another often recommended practice in disease management,especially for soil-borne diseases (see section 3.12).145 Cabbage Ecological Guide - 2000
Disease EcologyWhen resistant varieties are not available, find out some more details on the disease. Start for examplewith: where does the disease come from? How does it spread?Knowing characteristics of a disease will give you clues on how to manage it !The table 7.9 below will summarize some sources and carriers for a number of important cabbagediseases.Table 7.9 : A summary of some sources and carriers for important cabbage diseasesDISEASEcontaminatedseedsotherinfectedplantsSOURCE(S) and/or CARRIER(S)diseasedcropresiduessoilcontaminatedwatercarriedby windcontaminatedtools, people,animalsdamping off - + + + + - +black rot + + + - + - +soft rot - + + - + - +Alternarialeafspot+ + + - - + +club root - + + + + - +downymildew- + + - - + +black leg + + + - + + +By checking the “+” symbols, you can see what the important sources and carriers for a disease maybe. Next thing is to see if these sources/carriers can be influenced. By eliminating or reducing a sourceor a carrier of pathogens, disease may be reduced! Some examples of management practices are listedbelow. This list is not exhaustive, check sections on individual diseases for a complete set ofmanagement practices.Cabbage Ecological Guide - 2000146
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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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Page 110 and 111: Major Natural Enemies of Cabbage In
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Page 144 and 145: Disease Ecologygrowth malformations
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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
Page 156 and 157: Major Diseases of CabbageOnce there
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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 172 and 173: Major Diseases of CabbageNitrogen (
Page 174 and 175: Weed Management9WEEDMANAGEMENTSUMMA
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Page 178 and 179: Weed Managementcompost or it may be
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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
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Literature and Internet Reference L
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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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