Perdidas En Rendimiento (Daño Simulado) Causadas Por Erinnyis Ello (L.) Y Niveles Criticos de Poblacion En Diferentes Etapas de Desarrollo En Tres Clones de Yuca

Erinnyis ello (L.) is considered one of the most important pests of cassava due to the severity of its damage. The objective of this study was to quantify the losses on root yield, planting material and percentage of starch in two different ecosystems by means of simulated damage. In some treatments plants were completely defoliated once; in others, plants were completely defofliated twice with the second defoliation one month after the first. Both types of treatments were carried out with plants of differente ages. A total of 4 experiments were conducted in Santander de Quilichao (Cauca), a site with poor soils, and a CIAT-Palmira (Valle) a fertile site. The number of fifth instar larvae needed to cause the defoliation estimated from data on leaf area and E. ello consumption rates was determined. Three clones of yuca were used, M Mex 19 CM 305-41 and HMC 2 with wide, intermediate and narrow leaves respectively. The results showed that yield loss in sites with poor soils can reach 64% when there are two consecutive defoliations and 46% after one defoliation. In fertile soils losses reached 47 and 25.50/0 with two and one defoliation respectively. The greatest losses of planting material resulted when plants were defoliated twice at one and two months of age, and once at one month of age. These losses were 72 and 62% respectively. Decreases in percentage of starch in the roots occurred when plants 7 months old or older were defoliated.