An increase in cereal leaf beetle sightings has prompted NIAB TAG to reassure growers that in the majority of cases it will not affect yield, while treatments applied for other insects will also control this pest.
Despite the small size of the flag leaf in many crops, damage by the cereal leaf beetle will rarely exceed the 10-15% of photosynthetic area that would be ’cause for concern’.
’During the larval phase they feed on the surface of the leaf, eating the surface layers ’ including the photosynthetic cells - leaving a translucent stripe’, explains Richard Overthrow, technical services manager at NIAB TAG.
’A couple of stripes are no reason to get worried; it is only when these areas cover more than 10-15% of the leaf that you would consider using a spray. For instance, if activity is persistent and the flag leaf is particularly small, in barley, say.
’And even then, if you are tackling orange wheat blossom midge or aphids, the same insecticide will also target the cereal leaf beetle. A pyrethroid-based product will do the job,’ he says.
Mr Overthrow is keen to point out that the window during which the cereal leaf beetle will damage crops is short. ’The larvae will be active for a maximum of two weeks before pupating and dropping to the soil.’
The beetles are dark with orange colourings on their legs and behind the head. The larva is short, fat and pale but covers itself with its own excrement, giving it a dark brown appearance.
