Cabbage Integrated Pest Management : An Ecological Guide.

Major Agronomic PracticesSome examples of main crop families:CrucifersSolanaceousLegumesOnionsCucurbitscabbage, Chinese cabbage, radish, cauliflower, pak choi, broccoli, turnip,mustard, rapetomato, potato, pepper, chili, eggplantall types of beans, all types of pea, groundnut, alfalfa, cloversonion, garlic, shallot, leekcucumber, gourds, luffa, melons, pumpkins, courgetteRotation is most effective against diseases that attack only one crop. However, controlling the manydiseases that infect several crops in the same plant family requires rotation to an entirely different family.Unfortunately some pathogens, such as those causing wilts and root rots, attack many families androtation is unlikely to reduce disease.In addition, some fungi produce resistant, long-lived reproductive structures as well as the immediatelyinfectious forms. For example, the black sclerotia produced by the fungus Sclerotinia can survive foryears. Pythium and Phytophthora can also produce long-lived resting spores. Such spores help thesefungi to survive during a long time without a host. How long such pathogens can survive without a hostplant depends on factors like environment, temperature, ground water, etc. Some indications on “survivalrates” per disease are mentioned in the sections on individual diseases. A few examples:Disease Can stay alive in soil without cabbage plant for ..Black rot 1- 2 yearsBlack leg 2 -3 yearsClubroot 7 - 20 yearsNext to this, you can set up a small study as described below to check if soil-borne pathogens like blackleg, are still present in a field.How to check for soil-borne cabbage pathogens in a field:Plant a non-cruciferous crop in yourfield but leave about 2 or 3 small areaswithin the field which you plant withcabbages. These are your test areas.Check at regular intervals whether anysoil-borne diseases occur in the testareas. When you find a disease, youknow it is still there and you will haveto wait at least one more seasonbefore planting cabbages or anothercruciferous crop again. Check if theresmall area planted with cabbagestill are old cabbage leaves in theneighborhood of your field or in the soilwhich can be the source of infection. These should be removed and destroyed.rowsanothercropWhen no disease occurs you can try planting cabbages again in the whole field next season.GIt should be stressed that this test is not 100% proof! Soil-borne diseases are often patchy and asuccessful test may not give a 100% guarantee that there are no soil-borne diseases. The more testareas you try, the more chance there is to “hit” a soil-borne disease.Related exercises from CABI Bioscience/FAO manual:2-A.1. Importance of crop rotation49 Cabbage Ecological Guide - 2000