The biology and ecology of Bruchus rufimanus (bean seed beetle)

Abstract

The bean seed beetle, Bruchus rufimanus (Boheman), is an economically important pest of Vicia faba bean crops throughout Europe and has become established as a serious pest in the UK since 1990. Damage reduces the value of the dried V. faba crop and the presence of larvae or unemerged adults in the beans results in crop rejection for all the main quality markets. The life cycle is not completed in fresh harvested broad beans, but immature beans show damage and contain the pest larvae. Affected broad beans crops are rejected, resulting in a total loss to the grower. The main objectives of the research were as follows: to improve knowledge of factors influencing the emergence of insects from their over-winter habitats and factors leading to the termination of diapause; to improve knowledge of conditions that influence oviposition and damage, such as feeding opportunities, temperature, photoperiod and pollen type needed to stimulate oviposition; to improve knowledge of factors influencing the selection of or preference for over-wintering habitats; and to investigate the distribution of the pest throughout the UK. The influences of host plant sowing date, cultivar and density were investigated. The research provided evidence for the influence of temperature on damage caused by B. rufimanus and provided guidance for the distribution of the pest across the UK, allowing growers to plan insecticide applications according to regional pest pressure. It has been possible to link these findings with data supporting improved cultural methods of reducing the impact of the pest, particularly the timing of sowing.