Preliminary studies of the chisas (Coleoptera: Lamellicornia) from San Antonio, Cauca. Records and observations in Laparosticti and Pleurosticti

Abstract

The cassava crop (Manihot esculenta Crantz) in San Antonio (Cauca) (1100 masl, 1200 mm/ year, Tropical Dry Wood-Premountain Wet Wood) has significative phytosanitary limita­tions originated by white grubs with root feedings habits of a Dynastinae, Melolonthinae and Rutelinae complex. The diminishing in the profit crops, the farmers' economical in­ability to face this problem, and the disregard of the agroecological management of the root white grubs motived the beginning of this basic research in Lamellicomia, with the pur­pose of obtaining the taxonomic identification and ecological remarks of the collected species. A capture system with five light traps during three consecutive semesters (1.991-1.993) was used. The captured product was picked up weekly. This work was complemented with field observations and grub immature stages to rear in the laboratory. The capture had a total of 37.857 Lamellicornia specimens of which 34.543 belong to Pleurosticti species of the Melolonthidae family in this way: Dynastinae 28,332 (82.0%), Cyclocephala amazona, C. fulgurata, C. ruficollis, C. spp, C. mafaffa, Ligyrus spp., Dyscinetus, Podischnus agenor, Stenocrates sp. andAspidolea spp.; Melolon­thinae 5,283 (15.3%) genera Phyllophaga,Plectris, Ceraspis, and Macrodactylus; Rutelinae 928 (2.7%) Anomala spp. and Pelidnota sp. Graphically it was showed the influence that the moon cycles and the rain­falls have on the population levels of the pho­totropic white grubs. The total capture also in­cluded 3,314 Laparosticti specimens belong­ing to Aphodiinae, Troginae, Geotrupinae, Dichotomius, Pinotus sp., Oxisternon, Ontherus, and Onthophagus. These groups are innocuous to the agriculture and with great ecological importance by their degradation functions for which are recommended agroecological activities to preserve the zone 's biodiversity.