An Ecological Study of the Lima-Bean Pod Borer, Etiella zinckenella (Lepidoptera: Phycitidae), in Southern California1

Abstract

Ecological studies of the lima-bean pod borer, Etiella zinckenella (Treitschke), conducted in a coastal area of southern California during 1963 and 1964, revealed that 3–4 larval generations occurred on lima beans between planting in April and cessation of growth in January. The population reached its peak in September during the second generation with 123 larvae per 100 pods in 1963 and 140 in 1964, resulting in 71% and 76% pod infestation, and 47% and 49% bean injury, respectively. Overall pod infestation was 21.5% and 26.8%, and bean injury was 12.7% and 15.9%, in 1963 and 1964, respectively. Four larval parasites were reared, including Bracon platynotae (Cushman), Bracon sp., Perisierola cellularis (Say), and Zatropis tortricidis Crawford, with the last-named accounting for about 94% of the total parasitization each year. Parasitization reached identical peaks of 28% on October 22, 1963, and on November 10, 1964. Larval mortality (nonpathogenic) reached a peak of 43% on August 13, 1963, and 36% on November 17, 1964. Total larval mortality (dead and parasitized) reached peaks of 57% and 45% on August 13 and November 10 in 1963 and 1964, respectively. Overall larval mortality was 8.8% and 6.4%, including 5.6% and 4.3% dead, and 3.2% and 2.1% parasitized larvae in 1963 and 1964, respectively.