Wheat blossom midge – to spray or not to spray

ADAS, the UK’s largest provider of expert solutions and policy advice on rural business and environmental issues, has recently completed a project for LINK. The application of the results at ADAS Boxworth has resulted in restricting the use of insecticide treatment for orange wheat blossom midge to just two commercial fields of susceptible varieties on the whole farm.

This project involved the use pheromone traps, which were baited with the chemical released by female midges to attract males at a time when the females will search for wheat during the ear emergence stage to lay their eggs.

The aim of this project was to determine how many traps are needed to assess the risk of midge attack and where best to place them. They were sited in 24 fields at ADAS Boxworth, with the objective of identifying when and where the midges are hatching and which crops are most at risk from damage.

Nearly half the midges caught were found in a crop of winter beans. The soil conditions under this type of crop are warmer and wetter, which encourages a greater proportion of the hibernating larvae to pupate. The study discovered that the risk from within most wheat crops was low and growing the resistant variety, Robigus, has meant that the fields can be left unsprayed.

ADAS entomologist, Jon Oakley said “The general feedback from across the country has been that pheromone traps have allowed farmers and agronomists to identify where wheat blossom midge is a risk in a year of very patchy incidence. This will help to control the pest where necessary, without the recourse to unnecessary treatment in response to last year’s high levels of attack.”