AHDB Horticulture funded Project TF 204 assessed the effectiveness of the computer based life-stage simulation model RIMpro-Cydia at forecasting egg laying.
- The RIMpro-Cydia model was found to be a useful indicator of egg-laying risk but needs calibrating.
- A threshold ‘risk factor’ of 100 tends to overestimate the risk of egg laying and larval emergence which, if the model is used alone to time control sprays, can result in applying more sprays than may be necessary.
- It’s also difficult to set the parameters of the model to produce a reasonable prediction of the risks from second generation egg laying.
- Use of the RIMpro-Cydia model in conjunction with pheromone trap records – only spraying if the forecast indicates a risk of egg laying and the pheromone trap threshold is exceeded – will help avoid unnecessary early sprays when males are flying and there is little or no risk of egg laying.
- The results of the project suggest that the interval between sprays should be shortened where crop damage from codling moth was significant in the previous year or when weather is hot, and highlights the importance of continuing to monitor and treat for the pest in August and September.