Update on diamondback moth (Plutella xylostella) insecticide resistance and the vegetable brassica insecticide management strategy
The market for organic food products in the Netherlands is growing; however, supply shortages are hampering the grow th of the market. The Republic of South Africa (RSA) has the advantage of being able to produce organic food products during the European winter seas on, as it is located in the southern hemisphere. Sourcing organic products from the RSA could therefore amelio- rate the current shortness of supply.
Turnip Mosaic Virus (TuMV) infects most cruciferous plants, but is most damaging in Chinese cabbage, turnip, mustard, and radish. The most common symptom in these crops is a distinct mosaic of light and dark green colors in the leaves. Depending upon the virus strain and the crop species, necrotic streaks, flecks, or ringspots may also occur. Necrotic spots and ringspots are the primary symptom in common cabbage, but the severity of symptoms is cultivar dependent.
Symptoms occur in cabbage and Brussels sprouts. As the heads approach maturity, inner leaves become necrotic along their margin. Margins of one or more leaves turn brown beginning at the leaf pores. The area affected may be a narrow band or involve up to half of the leaf. Symptoms occur at one time and are not progressive. There is no external evidence that the heads are affected by tipburn.
Organic farmers rely primarily on preventive, cultural, and integrated methods of pest and disease management. Additionally, there are a number of materials that can complement and support organic management. This guide was developed to provide a useful and scientifically accurate reference for organic farmers and agricultural professionals who are searching for information on best practices, available materials, and perhaps most importantly, the efficacy of materials that are allowed for use in organic systems.
Xanthomonas campestris pv. campestris
Black rot occurs on all cultivated crucifers and several wild species. Lesions typically begin at the leaf margin and progress inward forming V-shaped chlorotic lesions. With time the lesions begin to dry and become necrotic. Infection normally occurs through leaf pores, but it can occur any place on the leaf where insect or mechanical wounds allow for bacterial entry.
Erwinia carotovora subspecies carotovora, atroseptica and chrysanthemi