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Desk study to apply knowledge developed for conventional horticulture to control of pests in organic vegetables - OF0179

This study will aim to demonstrate how methods of pest control developed for conventional vegetable production can be adapted for use by organic growers. The study will concentrate on pests of umbelliferous and cruciferous crops and will be composed of 11 specific objectives outlined as follows, together with ways in which they might be achieved: 1. Adaptation of the existing carrot fly forecast to quantify how the date of crop drilling influences subsequent fly pressure. The carrot fly forecast produced at HRI Wellesbourne will be used to predict the proportion of the first generation of flies that will lay eggs on carrot crops drilled on different dates. The model will also be used to predict the timing of emergence of the subsequent fly generation within the crop. It will then be verified using data from experimental carrot plots located close to the source of the main carrot fly population at HRI; these data will be incorporated into the existing carrot fly forecast model; 2. Production of a model to quantify how crop damage can be reduced by altering the harvest date. A sub-model based on published and field data will be incorporated into the carrot fly forecast model, together with meteorological data; this model will be calibrated with experimental data collected from carrot plots at Wellesbourne; 3. Identification of times at which crops should be covered to reduce carrot fly damage. Output from the carrot fly model will be modified to identify the times at which crops should be covered and the dates after which it is safe to uncover crops for operations such as weeding; 4. Quantification of the contribution possible from host plants with various levels of resistance. Data collected at HRI Wellesbourne will be used in simple mathematical models to quantify how partial plant resistance can contribute to the reduction of carrot fly damage alone or in combination with other damage reduction techniques; 5. Verification of carrot fly control strategies. Information collected in objectives 1-4 will be used to produce a strategy for reducing carrot fly damage in organically grown umbelliferous crops; this will be evaluated by HDRA in commercial carrot and parsnip crops where there are high and low levels of infestation. Objectives 6-11 will focus on pests of cruciferous crops; 6. Adaptation of the existing pest forecasts to quantify how the judicious choice of planting and harvesting dates can be used to reduce crop damage. Existing forecasting systems for pollen beetle, cabbage root fly, cabbage aphid, diamond-back moth, small white butterfly, cabbage moth and garden pebble moth will be used to identify the periods when cruciferous crops are at risk from each of these pest species. Forecasts will be verified by experimental data obtained from cabbage plots; 7. Identification of crop/pest situations where application of crop covers would be advantageous. A literature review will be conducted to identify crop/pest combinations where it would be advantageous to apply covers to exclude insect pests; results from relevant field experiments will also be included; 8. Evaluation of simple methods for inspecting crops to determine the presence or absence of any given pest species. A literature review will be conducted, including results from studies involving sampling aphid and caterpillar pests within cruciferous crops; 9. Identification of critical periods during which control measures should be applied. The literature will be reviewed to indicate the best time to apply the various control measures available to organic growers. Output from models of pest activity will be modified to indicate the most appropriate timings for application of each control measure; 10. Verification of the pest control strategy arising from work conducted in objectives 7-10. This strategy will be underpinned by the pest forecast models and will be presented as a MORPH decision support system. The strategy will be evaluated in an organic cropping system by growing crops of cauliflower and cabbage in locations with different levels of pest infestation; and 11. Production of a user-friendly format for disseminating the information produced in the study to organic growers. Information will be provided in the form of a decision support system in MORPH, articles in grower publications, through the advisory network and at annual meetings for organic growers.
Project Documents
• Final Report : Desk study to apply knowledge developed for conventional horticulture to control of pests in organic vegetables   (157k)
Time-Scale and Cost
From: 1999

To: 2002

Cost: £89,179
Contractor / Funded Organisations
Henry Doubleday Research Association, Horticulture Research International
Organic Farming              
Fields of Study
Organic Farming