SF 74 is due to finish in 2011 but grower trials are already demonstrating promising results. Raspberries are very susceptible to Botrytis, powdery mildew, raspberry beetle, cane midge, aphids and the viruses they spread. Intensive use of pesticides to control these problems is undesirable and unsustainable. The first three years of the project have worked on an integrated pest and disease management (IPDM) programme now being tested in large-scale trials. In 2009, the IPDM programme gave the same yield as growers' standard regime.
Cane density has a critical influence on the risk of cane Botrytis - an open canopy structure should be maintained by thinning. Prompt removal of spent floricane after harvest in August is also important for good crop hygiene, which combined with rapid fruit cooling and high-quality cool chain marketing can avoid the need for Botrytis fungicide sprays.
Powdery mildew fungicide should be applied in spring as soon as the tunnel is covered. If the disease is seen later, potassium bicarbonate sprays can eradicate.
Raspberry beetle is monitored by a new design of funnel trap, baited by a lure available from Agrisense. Catches inform decision making on timing or need for sprays of Calypso at the start of flowering. Sex pheromone traps inform whether raspberry cane midge needs to be treated. Applications of aphicide in October reduce spring populations of large raspberry aphid by more than 90 per cent.
Horticultural Development Company
For details on all HDC activities, visit www.hdc.org.uk.