For both tarnished plant bug and leafminer, no pest control decisions need to be made until tight cluster at the earliest. In next week's issue, we will include updated thresholds for treatment of both pests. Now is the time to begin 2 to 3 consecutive oil sprays on pears as an egglaying deterrent and egg suffocant. The only constraining factor to this method is the potential for cold weather at night. We do not advise applying an oil spray if the temperature is expected to drop below 40 F during the night following the oil spray or on the second night after application.
Low temperatures following an oil application can cause serious injury to developing tissue.
Healthy Fruit is written by Dan Cooley, Ron Prokopy, Starker Wright, and Wes Autio, except where other contributors are noted. Final copy is edited by Dan Cooley. Publication is funded in part by the UMass Extension Agroecology Program, grower subscriptions, and the University of Massachusetts IPM Program. Please cite source if reprinting information.