Obliquebanded leafroller (OBLR), Choristoneura rosaceana (Harris) is widely distributed in North America where it causes direct and indirect damage to several fruit crops and nut crops. A braconid parasite, Macrocentrus iridescens (French) is frequently associated with OBLR infestations in California pistachio orchards. We monitored OBLR and M. iridescens season-long field population dynamics, including overwinter behaviors; the temperature-dependent development of M. iridescens was evaluated using incubators at eight constant temperatures regimes. Results show that OBLR on pistachios has a partial third generation. It overwinters as early instars larvae on small cracks, loose bark, and crevices on the tree. M .iridescens lower temperature development threshold is 7.6oC; highest development rate was at 28oC (36.1 days in average). Development time ranged from 115.8 to 36.5 days at 13.9 and 25.8oC, respectively. M. iridescens overwinters in the OBLR larva and produces one generation for each generation of the host. The partial third OBLR generation allows M. iridescens to build to large numbers, parasitizing >70% of OBLR larvae in August and September collections.
Species 1: Hymenoptera Braconidae Macrocentrus iridescens
Species 2: Lepidoptera Tortricidae Choristoneura rosaceana (obliquebanded leafroller)
Keywords: Biological Control, Population Dynamics
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