POSTED IN For Growers ON 6/3/2016
Apple curculio are making their appearance as most sites are in petal fall. Insect activity has really picked up due to recent warm weather. Sweep net samples at the research center planting caught saskatoon sawflies (lower numbers than last week), apple curculio (first detection this year), tarnished plant bug, leaf-feeding weevils and several types of small moth caterpillars. There were also many beneficials in the sampling—spiders and parasitoid wasps. Unfortunately the threat of fruit losses from sawflies and curculios outweigh the current value of the beneficials, so it is advisable to protect the fruit with an insecticide at this time. Avaunt, Actara and Assail are likely to be the best choices where apple curculio is known to be a problem. It is also time to start protecting fruits from rust and entomosporium spot disease, especially with the threat of rain later this week. Tilt or Quilt Xcel, if not already used this year, would be good choices now. These have a 30 day PHI, so they do not fit well in your disease management program after we get into June.
Apple curculio adults are small and easily overlooked. They have tiny jaws at the end or a prolonged snout, which they use for cutting a uniquely shaped egg-laying slit into the surface of berries. The grub stages of the curculio feed inside the fruit.
Duke Elsner, Small Fruit Educator, Michigan State University Extension firstname.lastname@example.org