No abstract

No abstract

No abstract

Blueberry gall midge, Dasineura oxycoccana (Johnson), is a pest of cultivated blueberries throughout the world. Larvae feed and develop in developing leaf buds, and also in flower buds of rabbiteye blueberries, which causes buds to fall off the plant. These injuries can cause up to 80% yield loss in heavy infestations. As the larvae are protected from insecticides, adults must be targeted with foliar applications. Consequently, the detection of adults through an effective monitoring program is critical to time insecticide sprays against the blueberry gall midge. Understanding the distribution of the midge and its parasitoids is also important information for developing a more effective pest management program. A comparison of three monitoring trap types demonstrated that bucket emergence traps and clear panel traps captured similar numbers of midges, although the bucket trap is more sensitive at low population levels. Using bucket emergence traps, we found that nearly 80% of the midges collected pupated within 48 cm of the blueberry bush, suggesting that a targeted soil treatment may be a viable integrated pest management tactic that could be included in a midge management program. Traps and bud samples demonstrated that adult and larval midges and parasitoids were randomly distributed throughout the field in both years, with the exception of larval aggregation in early 2012. As parasitoid distribution is parallel to host occurrence within blueberry plantings, this increases the potential for biological control activities against the blueberry gall midge in fields that do not receive broad-spectrum insecticide applications.

Where a female places her eggs can have a major impact on the fitness of her offspring, especially for insects in which the winged adults are far more mobile than the neonates. Larvae of Heliothis subflexa (Guenee) (Lepidoptera: Noctuidae), a specialist moth phylogenetically nested within a generalist clade, feed only on fruit of some Physalis species. Field observations of the oviposition behavior of H. subflexa revealed that 1) females laid most of their eggs on leaves of the Physalis plant, despite the larvae's frugivorous diet, and 2) females laid nearly 20% of the eggs on nonhost plant species. Most eggs oviposited on nonhosts were placed close to the host plant-88% were within 15 cm of the Physalis plant. However, in a study of neonate movement, we found that a distance of 2 cm from the hatch site to the host plant significantly decreased the ability of neonates to establish on the host plant. The estimated fitness cost, quantified as reduced neonate survival, for females ovipositing on nonhosts is 8-17%. Many ecological and evolutionary factors could result in oviposition on less suitable host parts and on nonhosts. One possibility is that specialization on Physalis has recently evolved in H. subflexa, and females have not fully optimized their oviposition behavior. However, the fitness cost of oviposition on nonhosts may be balanced by fitness benefits of such behavior, such as faster decision-making and reduced predation.