Minimising pesticide residues in strawberry through integrated pest, disease and environmental crop management
Abstract: In a five year Hort-Link funded project an Integrated pest and disease management programme (IPDM) was developed for strawberry production over three years. In the final two years the programme was evaluated on commercial fruit farms for economic performance, effects on yield, fruit quality, pests, diseases and beneficial insects and the incidence of pesticide residues in the fruit compared to a conventional grower production programme (GS). In the IPDM programme, management of Botrytis fruit rot was based on the use of Botem, a forecasting model, to determine disease risk periods and bumble bees were used to vector bio-control agents (BCAs) to flowers. The use of conventional fungicides was restricted to pre-flowering and post-harvest use only. Management of powdery mildew was similarly based on a disease forecasting system to determine the risk periods and sulphur or potassium bicarbonate was used during flowering for disease control. The disease management strategies in the IPDM programme were, in general, successful, limiting Botrytis fruit rot and powdery mildew to acceptable levels, while showing a significant reduction in the number of pesticide residues in the fruit. Overall fruit yield and quality in the IPDM programme was equivalent to, or better than, that achieved in GS. We conclude that the IPDM programme developed can perform well, particularly in early season strawberry production when pest and disease risks are usually low. However, where pest and disease pressure was high the programme was less successful. So adoption of the IPDM programme by growers will require precise crop management. Further work is required to refine the models.