Biology and host specificity notes on Styphlus penicillus Gyllenhal (Coleoptera:Curculionidae), examined as a biological control agent for Crupina vulgaris in the United States with remarks on its host plant

Crupina vulgaris Cassini appeared in the field in southern France (depending on rainfall) by late September, early April, and early and late May, respectively. Mines of the weevil were found on cotyledons three weeks after the appearance of seedlings during early October, and were present until early April of the following year. Eggs were deposited on the bases of cotyledons, under the epidermis, from late September to early October. There are three larval instars. Larvae kept at 6 to 18 degrees C did not pupate but larvae kept at 15 to 28 degrees C pupated, in the soil. Adults fed briefly during May and June before hiding under stones to estivate until early September to October, depending on weather conditions. To obtain an indication of the weevil's host range, various crop plants were grown in a field where C. vulgaris and Styphlus penicillus Gyllenhal occurred. Some, including artichoke, were attacked by S. penicillus, indicating that its host range is too broad to permit its use as biological control of C. vulgaris.