Search

The location of wild and cultivated host plants by pepper weevil (Anthonomus eugenii Cano) may be aided by visual cues, the male-produced aggregation pheromone, herbivore-induced, or constitutive host plant volatiles. The attractiveness of constitutive plant volatiles to pioneer weevils is important in understanding, and perhaps controlling, dispersal of this insect between wild and cultivated hosts. Ten-day-old male and 2- and 10-day-old female weevils were tested in short-range Y-tube assays. Ten-day-old male and female weevils were attracted to the volatiles released by whole plants of three known oviposition hosts, 'Jalapeno' pepper, American black nightshade, and eggplant, as well as tomato, a congener, which supports feeding but not oviposition. Two-day-old females were attracted to all plants tested, including lima bean, an unrelated, nonhost plant. Fruit volatiles from all three hosts and flower volatiles from nightshade and eggplant were also attractive. In choice tests, weevils showed different preferences for the oviposition hosts, depending on age and sex. Upwind response of 10-day-old male and female weevils to host plant volatiles was also tested in long-range wind tunnel assays. Weevils responded to pepper, nightshade, and eggplant volatiles by moving upwind. There was no difference in the observed upwind response of the weevils to the three host plants under no-choice conditions. Reproductively mature pepper weevils can detect, orient to, and discriminate between the volatile plumes of host plants in the absence of visual cues, conspecific feeding damage, or the presence of their aggregation pheromone.

Weeds adjacent to commercial tomato production fields on the west coast of Florida were surveyed during 1982–1983 to determine which species serve as reservoirs of Agromyzidae leaf miners and their parasitoids. About 95% of the leafminer larvae were observed in foliage of seven weed genera ( Solanum americanum Mill., Erechtites hieracifolia (L.), Bidens alba (L.), Gnaphalium spp., Physalis spp., Sonchus spp., and Rumex obtusifolius L.) and volunteer tomato even though these species accounted for only about 13–42% of the weed canopy. Liriomyza trifolii (Burgess) and L. sativae Blanchard accounted for 45 and 40%, respectively, of the leafminer adults reared from infested foliage and were most prevalent from S. americanum and B. alba . The larval–pupal parasitoids Optus dissitus Muesebeck, Oenonogastra microrhopalae (Ashmead), and Halticoptera circulus (Walker) were the most abundant leafminer parasitoid adults reared from leafminer infested foliage, accounting for 37.8, 15.1, and 15.8%, respectively, of the total reared. The larval parasitoids Neochrysocharis punctiventris (Crawford), Diglyphus begini (Ashmead), and D. intermedius (Girault) accounted for 8, 5, and 2.5%, respectively.