Development of a decision support system for phoma and light leaf spot in winter oilseed rape (PASSWORD Project)

Summary

Sector:
Cereals & Oilseeds
Project code:
PR357
Date:
01 October 2000 - 30 September 2005
Funders:
AHDB Cereals & Oilseeds.
AHDB sector cost:
HGCA (Project 2155 - £148,546)
Project leader:
P Gladders1, C Dyer1, B D L Fitt2, N Evans2, F Vanden Bosch2, J M Steed2, A Baierl2, J Turner3, K Walters3, P Northing3, K Sutherland4, S Campbell5, D Ellerton6, A Selley7, B Hall8, D Naylor9 and C Parker10 1ADAS Boxworth, Battlegate Road, Boxworth, Cambridge CB3 8NN 2Rothamsted Research, Harpenden, Herts AL5 2 JQ 3Central Science Laboratory, Sand Hutton, York YO41 1LZ 4SAC Aberdeen, Ferguson Building, Craibstone Estate, Bucksburn, Aberdeen AB21 9YA 5HGCA, Caledonia House, 223 Pentonville Road, London N1 9HY 6ProCam Group Ltd, Saxon Way, Melbourn, Royston, Herts SG8 6DN 7Du Pont (UK) Ltd, Wedgwood Way, Stevenage, Herts SG1 4QN 8Syngenta Crop Protection UK Ltd, Whittlesford, Cambridge CB2 4QT 9The Perry Foundation, 31 Rossendale, Chelmsford, Essex CM1 2UA 10Computing Department, Glasgow Caledonian University, Glasgow G4 0BA

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About this project

Abstract

Pests and diseases in winter oilseed rape cause serious loss of yield and quality. Losses, predominantly from diseases, are estimated to exceed £80 million/annum in some years.  These losses have occurred despite an annual expenditure of about £3.5 million on insecticides and £9 million on fungicides. Decision-making is difficult because of complex spatial and temporal variation in pest and disease problems and improved guidance is required. The main objective of this project was to develop a decision support system for both pest and disease control in oilseed rape. 

A new regional forecast for stem canker incidence pre-harvest was developed and is available on the Internet. Models for predicting the severity of phoma stem canker in July were also produced and could be operated where spore trap records, leaf surface wetness and temperature data are available. A regional light leaf spot forecast was produced annually and validation during the project showed that 86% of regional predictions were reliable. In addition to regional disease forecasts, crop-specific risk assessment methods were developed that predict the onset of phoma leaf spotting using post-harvest weather data and thermal time relationships for canker development and canker severity. Yield loss can then be calculated from canker severity and the economic impact of stem canker predicted.

Analysis of historic datasets and field experiments within the project indicate that considerable yield loss (up to 0.07 t/day) can occur if fungicide treatment is made after light leaf spot symptoms have appeared. For stem canker, only moderate and severe lesions cause loss of yield and these can be controlled using a two-spray programme applied when phoma leaf spots first appear and 4-6 weeks later. The most effective disease control was obtained using a combination of resistant cultivars and fungicides. In some years, responses to fungicides were not cost-effective and targeting their use to high risk situations is necessary to give the best margins over input costs.

Close contact was maintained during the project with potential users who influenced priorities and design features. A prototype decision support system was produced that provides guidance for managing invertebrate pests, phoma stem canker and light leaf spot. The system is compatible with ArableDS and is now undergoing a two year test phase to evaluate the new disease models.

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