Cross-resistance between the Mexican Rice Borer and the Sugarcane Borer (Lepidoptera: Crambidae): A Case Study Using Sugarcane Breeding Populations

The sugarcane borer (SCB) [Diatraea saccharalis (F.)] and Mexican rice borer (MRB) [Eoreuma loftini (Dyar)] are two economically important pests of sugarcane (Saccharum spp. hybrids) in the United States. Because of similarities in larval feeding behavior, selecting for resistance to one species could provide resistance to the other, a phenomenon we have termed “crossresistance”. The objective of this study was to determine if SCB-resistance in sugarcane is correlated with resistance to MRB. Thirty genotypes from Louisiana previously identifi ed as either resistant or susceptible to the SCB and 50 from Texas with unknown resistance status to either species were evaluated for percent borer-damaged internodes. Data from the SCBresistant and-susceptible genotypes were used to determine the SCB-resistance status of all 80 genotypes. Similar (P = 0.578) levels of MRB damage were found between the Louisiana and Texas population, whereas, the Louisiana population suffered signifi cantly (P < 0.05) less SCB damage compared to the Texas population. The SCB-resistant genotypes suffered signifi cantly (P < 0.01) less damage from the MRB compared to their susceptible counterparts. A signifi cant (P < 0.001) association was found in percent SCBand MRB-damaged internodes among the Louisiana and the SCB-resistant populations but not among the Texas or SCB-susceptible populations. Furthermore, the SCB-resistant genotypes were 40% less likely than susceptible ones to be bored by the MRB. Resources developed for SCB-resistance could form the foundation material to breed for resistance to both pests. M. Zhou, South African Sugarcane Research Institute, 170 Flanders Drive, Private Bag X02, Mount Edgecombe, KwaZulu-Natal 4300. C. Kimbeng, School of Plant, Environmental and Soil Sciences, Louisiana State University Agricultural Center, Baton Rouge, LA. J.A. da Silva, Texas Agricultural Experiment Station, Weslaco, TX. W.H. White, USDA, ARS Sugarcane Research Laboratory, Houma, LA. Received 13 July 2009. *Corresponding author ([email protected]). Abbreviations: MRB, Mexican rice borer; SCB, sugarcane borer. Published in Crop Sci. 50:861–869 (2010). doi: 10.2135/cropsci2009.07.0382 Published online 11 Mar. 2010. © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved. No part of this periodical may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or any information storage and retrieval system, without permission in writing from the publisher. Permission for printing and for reprinting the material contained herein has been obtained by the publisher.