Pests and disease

Organic growers also use biological control. They are allowed to import natural enemies of pests. This works either through predation or parasitism. This has proven effective for the control of red spider mite and specific caterpillars, and does not affect other insects. And a third technique is to use insect traps ranging from sticky yellow strips to pheromone or sexual lures. The pheromone traps use synthetic extracts of the chemical scents that 

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New cocoa hybrids and selections have been developed in Malaysia and other countries that produce significantly higher yields in select soil and climate conditions. In addition, high density plantings have demonstrated higher and earlier yield in Malaysia and the Philippines. Low or no shade cocoa has also proven to increase yields. However, both high density and reduced shade cocoa production requires additional inputs of management and nutrition. Additional inputs to control pests and diseases also maybe required. 

Although winter wheat is grown on more land than any other crop in England and Wales, it is not usually grown continuously, because of problems from pests and diseases. Break crops are grown to interrupt the build-up of these problems, so we need to look at the behaviour of nitrogen under these and other crops, but much less information is available than for winter wheat. 

Frevert J, Zietz E, Knoell HE. 1988. Residue-and groundwater analysis New techniques. Brighton Crop Protection Conference - Pests and Disease 727-731. 

F. Araki and K. Yabutani, a,a,0 -Trifluoro-3 -isopropoxy-o-toluanilide (NNF-136) a new fungicide forthe control of diseases caused by Basidiomycetes, in Proceedings of 1981 British Crop Protection Conference on Pests and Diseases, Vol. 1, pp. 3-9 (1981). 

Field beans grow well on clay soils and heavy loams, provided they are well-drained and limed (pH above 6). Winter beans are not frost hardy and so are risky to grow, north of the Midlands. In some rotations, beans replace the clover break and they are usually followed by wheat. Yields for spring and winter field beans are shown in Table 5.4. The problem with field beans is their variable yield, which is partly caused by adverse weather conditions and susceptibility to pests and diseases (winter beans get chocolate spot, spring beans are aphid prone), and partly due to the uncertain activity of the necessary insect crosspollinators. 

Parameters for integration of growth and differentiation Parameters for crop integration are incidence of pests and diseases (hypothesis, because no spontaneous pests and diseases occurred). Parameters for carrot integration are carotene content, orange colour of root (trend), saccharose content, total sensory appreciation and carrot taste. 

Impact of phytochemicals on crop resistance to pests and diseases... 

Based on the tendency for higher levels of phenolics in organically grown plants, these are potentially less susceptible to pests and diseases. Indeed, Schultz and Baldwin (1982) and Rossiter et al., (1986) observed that high phenolic contents reduced the size of female gypsy moth pupae, leading to a decline in reproductive production of female gypsy moths. 

More data on the effects of low level infestation by pests and diseases, which usually occurs in organic crops, on phytochemical induction and levels in harvested food material. 

As a result, organic fruit growers have to make maximum use of preventative or indirect plant protection measures, some of which were already described in terms of their effect on fruit quality (e.g. lower planting densities, see sections above). However, there remains an increased risk for pests and diseases causing stress, decreased photosynthetic activity and capacity. Also in certain sensitive cultivars, the application of permitted plant protection products (such as lime sulphur) can result in phytotoxic effects or latent stress in trees (Palmer et al, 2002). The decrease in photosynthetic activity by both pest/disease attack and pesticides may, in turn, result in reduced fruit quality. Both long-term latent and short-term acute side effects of organic plant protection products have not yet been sufficiently investigated. 

Evans V J and Jenkyn J F (2000), Fungicides for control of ergot in cereal crops , Pest and Diseases, Proceedings of an international conference held at the Brighton Hilton Metropole Hotel, UK, 13-16 November 2000, 511-514. 

Langer, V. (1995). Pests and diseases in organically grown vegetables in Denmark A survey of problems and use of control methods , Biological Agriculture and Horticulture, 12 (2) 151-171. 

Bewick DW, Hill IR, Pluckrose J, Stevens JEB, Weissler MS (1986) The role of laboratory and field studies, using radiolabelled materials, in the investigation of the degradation and mobility of tefluthrin in soil. Proceedings, BCPC Conference - Pest and Diseases, British Crop Protection Council, Brighton, 4B-2, pp 459-468... 

Matthiessen J, Kirkegaard J (2006) Biofumigation and enhanced biodegradation opportunity and challenge in soilborne pest and disease management. Crit Rev Plant Sci 25 235-265. doi 10.1080/07352680600611543... 

Glen DM, Wilson MJ, Pearce JD, Rodgers PB. (1994) Discovery and investigation of a novel nematode parasite for biological control of slugs. In Proceedings of the Brighton Crop Protection Conference, pests and diseases, pp 617-624. 

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