Impact of rice harvest height and ratoon cropping on late season and overwintering stem borer (Lepidoptera: Crambidae) infestations

A 2-yr field study in Texas compared infestations of the stem borers Eoreuma loftini (Dyar) and Diatraea saccharalis (F.) in rice (Oryza sativa L.) as affected by main crop harvest height and the production of a ratoon (second) crop. Substantial infestations (> 5.6 stem borers/m2) remained in rice culms regardless of harvest height (20 vs. 40 cm). However, the lower harvest reduced E. loftini infestations 3.4 to 5.4-fold whereas D. saccharalis infestations were not changed. This study also showed that rice stubble under favorable conditions represents an overwintering habitat for stem borers.