Evaluation of Certain Biological Control Agents of the Sugarcane Borer in Louisiana

Abstract

Field experiments were conducted during 1966 and 1967 in the Bayou Sec area of Assumption Parish near Napoleonville, La., to (1) evaluate, quantitatively, the relative importance of arthropod predators of Diatraea saccharalis (F.) by correlation between numbers of these predators and the degree of egg and larval mortality of the borers; (2) obtain qualitative evidence of predation through frequent and widespread field observations; and (3) study the feeding behavior and habits of the predators concerned. Average percent egg predation was higher during August and September than during June and July. Percent eggs destroyed by sucking predators was significantly higher than those destroyed by chewing predators. More predation was recorded during the night than during the day. Positive correlation coefficients were found between total numbers of predators (ant and spider populations) and percent egg predation. Spiders were found to be more closely associated with percent egg predation than ants. Percent recovery of sugarcane borer larvae was significantly higher in July than in June. Numbers of predators and percentages of hatchability had a more significant effect on percentages of larval recovery than numbers of sugarcane plants per stool. Predators that were observed feeding on the different stages of the sugarcane borer belong to the following taxa: Formicidae, Carabidae, Forficulidae, Elateridae, Chrysopidae, and Araneida.