Some factors influencing the efficiency ofApanteles medicaginisMuesebeck (Hymenoptera: Braconidae) as a parasite of the alfalfa caterpillar,Colias philodice eurythemeBoisduval

Invcsr igar ions were conducted to determine the more important factors influencing the efficiency of Apanteles medicaginis as a parasite of Colias philodice eurvrbeme, Studies on the rate of Colias development at various temperatures indicate that this insect becomes of economic importance only during periods of high temperatures. At low temperatures, the development time exceeds the time that elapses between cuttings of alfalfa. Thus, populations seldom, if ever, develop to economic proportions.