Development of an artificial larval diet for a new sugar beet pest, Aubeonymus mariaefranciscae (Coleoptera : Curculionidae), and its oviposition behavior

We have developed an artificial larval diet that can be used successfully f or rearing Aubeonymus mariaefranciscae Roudier from neonate to adult. Four artificial larval diets and fresh sugar beet petioles were tested. Petiole- fed larvae were unable to survive to pupae. The significantly higher surviv al rates and shorter developmental times obtained with diets containing sug ar beet root homogenate and vitamin mixture suggest that these nutritional components are essential for normal larval development. The best performanc e was obtained for those larvae fed on diet D, which had the highest surviv al rate (78%). Three consecutive generations were reared on diet D without significantly affecting their survival, developmental time, and reproductiv e capacity; however, adult weight was reduced. Four larval instars were rec orded and consistent data on their developmental periods were established. When whole plants were supplied, the preferred oviposition site was the roo t, where approximate to 40% of the eggs were laid in the crown, 57%, in the roots, and nearly 3% were laid on the leaf petioles. When detached leaves, inserted in moistened sand, were supplied, 91% of the eggs were laid in th e portion of the petioles below soil level and 9% on the aerial part. Adult s refused to oviposit on any of the artificial substrates provided. The egg s always were concealed in the plant tissues, which probably prevented them from desiccating and provided protection from potential predators.