Biology and host specificity of Gonioctena tredecimmaculata (Coleoptera: Chrysomelidae): a potential biological control agent for kudzu
Date
2006
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Publisher
University of Delaware
Abstract
Gonioctena tredecimmaculata (Jacoby) (Coleoptera: Chrysomelidae) was sent from China to the United States for testing as a potential biological control agent of kudzu [Pueraria montana var. lobata (Willd.) Maesen & S. Almeida]. In a quarantine facility, females kept on kudzu produced 2-4 larvae per day by ovoviviparous reproduction during most of the summer. Insect development was rapid, with larval and pupal stages taking 5.6 ± 0.08 and 9.6 ± 0.13 days at 25 °C, respectively. Larvae consumed a total of 16.3 ± 0.63 cm2, while adult beetles consumed approximately 5 cm2 of kudzu foliage per day. Newly emerged adults fed on foliage for approximately 15 days before digging into the soil for an apparent obligate diapause. These beetles mated and reproduced the following spring. ☐ The host range of this insect was tested using several native and agriculturally important plants related to kudzu under no-choice conditions. Both adults and larvae rejected most of the plants that were tested, but fed on soybean [Glycine max (L.) Merr.] and American hog-peanut [Amphicarpaea bracteata (L.) Fernald] in addition to kudzu. In a related study, host specificity tests investigated the response of G. tredecimmaculata to the growing condition of kudzu and soybean. Field- and greenhouse-grown foliage were used to determine if variable plant traits alter the response and specificity of a potential biological control agent in quarantine studies. Field foliage of both plants exhibited greater leaf toughness, higher total carbon content, higher trichome density per mm2, and reduced water content compared to greenhouse foliage. However, these traits did not influence insect fecundity, development time, female oviposition preference, or adult choice for field vs. greenhouse foliage of kudzu or soybean. Therefore, feeding and reproduction by G. tredecimmaculata on an agriculturally important plant, soybean, has led to its rejection as a candidate for biological control of kudzu. This work suggests that, despite significant differences in plant traits, greenhouse-grown foliage may be acceptable for use in host specificity testing.