Practice Abstract 35 - Bruchid beetle – control

Short title (native language): 
Bruchid beetle – control

Short summary for practitioners (native language): 
In-store
Traders may not accept field beans for any purpose with live beetles present. Although B. rufimanus does not re-infest stored beans, infested beans are best left on the farm until the emergence period is over, which in most years is complete by late October. If, however, this is not possible, then fumigation may be considered. Beetles may be killed by a recommended grain storage insecticide, but it is unlikely to control pupae or adults which have not yet emerged. Fumigation of beans intended for seed is possible.
In-field
The timing of sprays is critical to prevent egg-laying as control of larvae is not possible. During flowering examine crops for adults by tapping flowering stems onto the hand or a tray. Some insecticides may be used in field and broad beans during flowering and control is improved by combining spray timing with temperature forecasts.
Apply a spray when adults are found in the crop, 50% of the bean plants have first pods on lowest trusses and recorded maximum daily temperature has reached at least 20°C on two consecutive days. Apply a second spray 7-10 days later. Research has shown that if the spray is applied through angled nozzles or twin caps angles both ways using a medium spray quality, control is significantly improved. Insecticide should be applied in the early morning or late evening to avoid direct contact with bees.
A forecasting system developed by Syngenta Crop Protection UK and PGRO, ‘BruchidCast’, is available at www.syngenta.co.uk/bruchidcast.