YELLOW APHID OF SUGAR CANE, SIPHA LAVA, POTENTIAL PEST OF PASTO CARIMAGUA, ANDROPOGON GAYANUS, IN THE EASTERN PLAINS OF COLOMBIA

Abstract

The grass Andropogon gayanus was re­leased under the name "Carimagua 1", as an important alternative for cattle feeds in areas of poor soils (oxisols and ultisols) of the tropics. The CIAT Tropical Pastures Program has been surveying the insects on A. gayanus since 1977. Results showed that only a few insect pests are associa­ted with this grass. Two potential pests of A. gayanus: the false armyworm Mocis latipes Cueree (Lepidoptera: Noctuidae) and the su­garcane yellow aphid, Sipha flava (For­bes) (Homoptera: Aphididae) have been reported so far. The importance of A. gayanus as one alternative grass for the tropics was a very good reason for carrying out the studies attempting to understand the behavior, the population dynamics, and some measures of control of S. flava. All these studies were carried out at the Carimagua Experimental Station, Colombia. S. A. Results indicated that this insect may cause a red-purple coloration of leaves of A. gayanus, affecting the leaves by drying them, reducing the yield, and affecting the nutritive value of this grass. High populations of the yellow aphid were recorded in Carimagua at the beginning of the wet season when the grass presents the maximum forage production. The high insect popula­tion was reduced by using high stock­ing rate and cultural practices such as burning and machine cuttings, prior to the beginning of the rainy season.