Pepper weevil

Abstract: 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.

Abstract: Pepper weevil, Anthonomus eugenii Cano, is the major arthropod pest of peppers, Capsicum spp. L., in tropical and subtropical America. Adult weevils feed and oviposit in buds, flowers, and, especially, fruit. Larvae develop and feed inside those plant structures, thus reducing crop yields. Management is difficult and requires precise knowledge of developmental times and thresholds for maximum efficiency. Therefore, the developmental biology and life history parameters of A. eugenii were characterized in the laboratory on Capsicum annuum ’Jalapeno’ fruits at seven constant temperatures ranging from 15 to 33°C. A. eugenii developed through three instars at all temperatures. Linear regression analysis estimated a lower developmental threshold of 9.6°C and a degree-day requirement of 256.4 for development from egg to adult. Fecundity increased with increasing temperatures to a maximum at 30°C but declined at 33°C. Net reproductive rate (Ro), intrinsic rate of increase (rm), and finite rate of increas...