Pear psylla adults are among the earliest pests to appear in tree fruit crops, and indeed after the warm temperatures of the past few days adults were found to be active in southern counties. The first eggs have not been observed but oviposition will most certainly begin within the next week if temperatures remain mild as they are forecast to do.Dormant oil applications are a standard practice for early season psylla control. Unlike applications made for scale control and mite suppression, oil acts less as an insecticide and more as a method of exclusion, since adults tend to not lay eggs on oily surfaces. Therefore oil needs to be applied as early as weather and soil conditions permit. Usually the first applications are made in southern counties from mid to late March.
These applications are useful throughout early bud stages and are generally long lasting: about 2 -3 weeks. In the dormant/delayed dormant stages apply 3 % of oil (3 gals/100 or 6 gals/acre), or 2 applications of 2% through the green bud stage (when buds are swollen and green tissue is present). Adjust rates downward for later stages: 2% from swollen bud through green bud, or 2 applications of 1% from green bud through white bud (flower parts are visible). During the delayed dormant stages the addition of a pyrethroid or a growth regulator such as Centaur or Esteem may improve control. Surround, a clay product, may also be applied with oil at a rate of 50#/ acre in the delayed dormant stages. Surround applications without oil can be applied through bloom to disrupt the entire oviposition period and has shown to provide good control of the first generation nymphs. See the 2015 New Jersey Tree Fruit Production Guide for more information.