Obliquebanded leafroller in cherry
As we move into cherry harvest, growers should be aware of obliquebanded leafrollers in orchards.
There has been evidence in 2010 that obliquebanded leafrollers could become problematic again this season – particularly that organophosphates have been the backbone of many of our cherry programs and the likelihood of organophosphates resistance in obliquebanded leafrollers. We are strongly recommending a caterpillar material (not organophosphates or pyrethroids) in the tank for both tart and sweet cherry, especially if growers had an issue with these pests last season.
Obliquebanded leafrollers overwinter as larvae, feed in the spring and into the summer, and pupate in late June. These adults mate and lay eggs, and the larvae that are present in sweet and tart cherry orchards are just newly hatched or large, late, overwintering generation larvae. As we had cool conditions this spring, there is potential for both overwintering and summer generation larvae to be present in orchards at this time. The noticeable difference, obviously, is the size of the larvae, and from past experience, smaller larvae are easier to kill than larger ones. However, growers will still need to control these caterpillars, no matter what the size, before harvesting their fruit.
We can make the assumption that if larvae are still present in fairly high numbers in the orchards, growers should assume they have no efficacy from organophosphates against obliquebanded leafrollers. Therefore, growers will need to apply a chemistry with a short pre-harvest interval (PHI) that will be effective.
We have three, new Lepidopteron materials that work well against obliquebanded leafrollers: Delegate (7D PHI), Belt (7D PHI) and Altacor (10D PHI). All three materials provide excellent control of obliquebanded leafrollers. Sevin and the pyrethroids have a three-day PHI, but older data tell us that these chemistries will not be effective due to cross resistance with the organophosphates.