Pear Psylla1: Population Suppression Through Host Plant Modification Using Daminozide3

Abstract

Two applications of the plant growth regulator daminozide at 2000 ppm, timed approximately 30 and 50 days following full bloom of Bartlett pears, resulted in reduced terminal shoot growth and subsequently in lowered pear psylla ( Psylla pyricola Foerster) nymphal densities, and in reduced honeydew fruit damage. Over a 3-yr. peroid shoot growth was reduced an average of 33%, psylla nymph density and damaged fruit were reduced 35 and 57% respectively, compared to the untreated check.