David Owens, Extension Entomologist, owensd@udel.edu
Tree Fruit
Scout for plum curculio. We have accumulated enough degree days to where they should be laying eggs. First egg lay occurs around 240–300 degree days; peak egg lay is predicted at 380-390 degree days. Apples are at risk once fruit reaches ¼ inch. Scout near woodlines where overwintering curculio migrate in from. Prior to fruitset, they can be monitored for with chemical lures in pyramid traps or circle traps. Otherwise, monitoring for 1% newly damaged fruit can be an effective monitoring strategy.
Blueberry
Some leafroller activity was observed at Carvel plots this past week feeding on blossoms. They glue plant material together and hide in the shelter. When disturbed the small green worm wriggles violently to escape. This can be a sporadic pest. New Jersey recommendations by Dr. Cesar Rodriguez-Saona are as follows “Monitor for larvae on flowers and leaf clusters using beat trays or visual inspection. Insecticide treatment is recommended when larval numbers are more than 1 larva per 100 flower and leaf clusters. If larval populations are above threshold and application is needed during bee activity, Intrepid or Bt products should be applied.”