Some orchards spray for light brown apple moth (LBAM) very early in the season – often when they catch the first LBAM.
However the ideal time to spray for LBAM is when trees have reached the green tip stage and LBAM numbers are above a threshold of 9 – 10 moths per trap per week.
LBAM are native insects that do not diapause (hibernate) over winter, and large numbers of moths are often caught when traps are set in September, before deciduous fruit trees produce leaves. It is important to wait for this post-green tip increase in moth numbers.
Once the numbers get to 9-10 moths per trap per week, consider a well-timed spray. By a ‘well-timed spray’ we mean aim for early (i.e. 3%) egg hatch. If you can, use something as soft as possible, such as a BT spray that is registered for this use. Timing and coverage are critical for an effective BT application, so if you are in area with lots of rain you might consider other insecticides.
And remember, in most cases it is not necessary to apply insecticides to control LBAM in regions where codling moth is endemic. Most insecticides using for codling moth are also registered for LBAM. Where a good program for codling moth control exists, LBAM is usually controlled without the need for additional sprays.
See article on Biofix and spray predictions for codling moth and LBAM
Article reviewed by Greg Lefoe (Agriculture Victoria)