ABUNDANCE AND PHENOLOGY OF PARASITOIDS OF THE SPOTTED TENTIFORM LEAFMINER, PHYLLONORYCTER BLANCARDELLA (LEPIDOPTERA: GRACILLARIIDAE), IN CONNECTICUT

Abstract

AbstractParasitoids of the trivoltine spotted tentiform leafminer, Phyllonorycter blancardella (Fabr.), were studied in Connecticut apple orchards to determine their relative importance, emergence patterns, and seasonal abundance. Sixteen parasitoid species, including 12 eulophids, emerged from mines formed by 4th- and 5th-instar leafminer larvae. The species were primary, secondary, or facultative secondary parasitoids. Five were new records. The braconid Pholetesor ornigis (Weed) was the most abundant in the first and third leafminer generations, and the eulophid Sympiesis marylandensis Girault was the most abundant in the second generation. Ratios of parasitoids to Phyllonorycter spp. were generally higher in samples from unsprayed trees than in those from sprayed trees. Major parasitoids usually emerged 1 to 4 wk before their larval hosts became plentiful. Sweep samples indicated relatively high abundance of one or both major parasitoids during the first and second leafminer generations. Monitoring of parasitoids and the judicious use of insecticides may have a critical role in pest management programs utilizing native parasitoids of leafminers.