Field Evaluations of Parasitoids of Larval Stalkborers Against Eoreuma loftini (Lepidoptera: Pyralidae) in Rice

Abstract

Five species of parasitoids of larval stalkborer were evaluated in Texas in 1987 against the Mexican rice borer, Eoreuma loftini (Dyar), in field enclosures in rice, Oryza sativa L. The braconids, Alabagrus stigma (Brullé) and Allorhogas pyralophagus Marsh, and the bethylid, Goniozus natalensis Gordh, each parasitized >5% of the available E. loftini. The braconids, Apanteles minator Muesebeck and Macrocentrus prolificus Wharton, parasitized <1% of the available hosts. Allorhogas pyralophagus parasitized the highest percentage of borers, including 65.6% of the fifth- and sixth-instar E. loftini. Alabagrus stigma and G. natalensis parasitized fewer borers overall, although parasitism by A. stigma averaged 21.2% of small E. loftini in the rice leafsheaths. Alabagrus stigma, A. pyralophagus, and G. natalensis are candidates for further evaluation in the event that E. loftini becomes a pest of rice in Texas.