THE BEAN POD BORERS IN PUERTO RICO

Abstract

Three species of pod borers, Maruca testulalis (Geyer), Etiella zinckenella (Treitschke), and Fundella cistipennis (Dyar), were found commonly in 1985-36 infesting wild and cultivated leguminous plants in all parts of Puerto Rico. E. zinckenella and M. testulalis were about equally numerous, but the latter, because it confined its attacks almost entirely to cultivated plants, was by far the most important economically of the two. F. cistipennis was the least abundant of the three species, and although it was found largely in cultivated plants, it was much less destructive than either of the other species. In addition to various legume crops the insects attacked several wild legumes, particularly Crotalaria incana L., one of the Island's commonest Crotalarias, and Canavalia maritima (Aubl.) Thou., commonly called the bay been. Some wild legumes, such as the wild lima bean (Phaseolus lunatus L.), and one of the commonest Crotalarias, (C. retusa L.), appeared to be highly resistant, if not inmune, to attack. The pod borers deposit their eggs on or near the blossoms and blossom buds, thereby assuring ample food for the newly hatched larvae. Most of the injured blossoms drop to the ground, and it is not uncommon to find hundreds of them on the ground under bean plants. Experiments conducted at Yauco, Isabela, and Mayagüez indicated that the pod borers could be successfully controlled by two 25-pound-per-acre applications of dust containing 80 percent of natural cryolite. Similar applications of pyrethrum dust were moderately effective, but the cost of the material was prohibitive. Dusts and sprays containing rotenone failed to provide satisfactory control. Observation of various varieties and types of lime beans indicated that the small-seeded lima bean, particularly the variety Carolina, was highly resistant to pod borer attack.