Winged wastrels

摘要

Late-sown wheats are more vulnerable to pest attack, and they may attract some unusual visitors. Spring-sown wheat doesn't often fall prey to gout fly. But then it's not often that drilling extends into May. Crops sown in February and March are usually too advanced by this time of the season to be considered a satisfactory food source for the larvae. So the adults fly on by to the newest leaves of young grasses to lay their small, white eggs. But not yet heading, later sown spring crops are a primetarget for egg-laying. The white eggs are laid singly on flag leaves about now, and those soon develop into larvae which burrow into the shoots. Plants which didn't have a chance to tiller can have their yield potential halved by the pest, warns ADAS agronomist, Jon Oakley. "Spraying gout fly isn't often justified, but this summer I would apply a pyrethroid insecticide if I could find a white egg on at least half of the flag leaves. And I wouldn't hang around because they will hatch out after a week orso. It may be too late if you can see swollen shoots and damaged lower leaves."