Invasive Pests for Fruit Growers: Aug 13, 2013

Spotted Wing Drosophila (SWD) trap captures continue to increase in all locations across the state. In some locations the numbers are very high (100-300 per trap), while most locations have under 50. Fruit infestations are being reported in primocane raspberries, blackberries, and blueberries. Growers who are harvesting very frequently are finding lower levels of damage than those who can't get their fields thoroughly harvested on a 2-3 day rotation (or less!). In addition, growers who have a spray program with intervals over 7 days are finding higher levels of infestation than those with 5-7 day intervals. This is true of both organic and conventional programs. Those adding sugar to the spray mix (except when using pyrethroids) are also reporting improved efficacy. For primocane raspberries it is recommended to thin the rows somewhat so that there is better air circulation and improved spray coverage in the canopy. As mentioned before, frequent harvesting and prompt refrigeration of harvested fruit help protect fruit quality of all susceptible fruit. See https://extension.umass.edu/fruitadvisor/spotted-wing-drosophila for monitoring, identification and management information.