Agricultural Insects of the Paraguayan Chaco

Abstract

The results of a 13-month study of agricultural insects in a remote region of the Paraguayan Chaco are reported. The most serious general crop pests are leaf cutting ants, the migratory locust (Schistocerca paranesis Burm.), and spider mites (Tetranyehidac). Cotton insects were studied in the most detail, with the cotton leaf worm (Alabama argillacea (Hbn.)), the cotton bollworms (Heliothis spp.), the pink bollworm (Pectinophora gossypiella (Saund.)), and the cotton stainer (Dysdercus pallidus (Blöte) considered as major pests. Oxycarenus hyalinipennis is present and possibly of considerable importance. Aphids, lacebugs, whitefly, a coreid, a lygaeid, a broad-nosed weevil, and a Diabrotica beetle are considered minor pests of cotton. A number of other phytophagous insects were found only occasionally on cotton. Several species of caterpillars are important some years on peanut foliage. False spider mites (Tenuipalpidae) are suspected of causing fruit scarring on tangerines and causing a toxin disease of oranges. Several species of moths inflict severe damage to citrus and guava by their feeding punctures. Climatic factors, particularly sporadic rainfall, and hot, dry, spring winds, as well as effective predation are considered phenomena responsible for the fact that some of the insect problems are less severe than those caused by the same pests elsewhere.