|Reay-Jones, Francis - LA AGRIC EXPT STATION|
|Wilson, Lloyd - TX A&M UNIV|
|Way, Michael - TX A&M UNIV|
|Reagan, Thomas - TAES-BEAUMONT, TX|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 24, 2007
Publication Date: August 1, 2007
Citation: Reay-Jones, F.P.F., Wison, L.T., Showler, A.T., Reagan, T.E., Way, M.O. 2007. Role of oviposition preference in an invasive crambid impacting two graminaceous host crops. Environmental Entomology. 36(4):938-951. Interpretive Summary: As the Mexican sugarcane borer, Eoreuma loftini (Dyar), moves up the Texas sugarcane-growing area of the Gulf Coast and into the rice and sugarcane, Saccharum spp., growing areas of East Texas and Louisiana, knowledge on crop preferences and varietal susceptibility and resistance is becoming important for management of this pest. The Mexican rice borer greatly preferred to oviposition on sugarcane than on rice, and although several free essential amino acids in sugarcane were correlated with oviposition in sugarcane, these associations were not evident in the poorer host, rice. This work shows that sugarcane is more important than rice in terms of Mexican rice borer reproduction and indicates physiochemical mechanisms that might be of key importance to the development of varietal resistance in sugarcane.
Technical Abstract: As the Mexican sugarcane borer, Eoreuma loftini (Dyar), moves up the Texas sugarcane-growing area of the Gulf Coast and into the rice and sugarcane, Saccharum spp., growing areas of East Texas and Louisiana, knowledge on crop preferences and varietal susceptibility and resistance is becoming important for management of this pest. Oviposition preference studies of the Mexican rice borer on sugarcane and rice, Oryzae sativa L., showed that drought stressed sugarcane was 1.8-fold more attractive based on egg masses per plant than non-drought stressed sugarcane. The E. loftini susceptible sugarcane cultivar LCP 85-384 was 1.6-fold more attractive than HoCP 85-845 based on eggs per egg mass. Egg masses were 9.2-fold more abundant and 7-fold larger when laid on sugarcane than on rice. Oviposition on sugarcane occurred exclusively on dry leaf material, and egg mass abundance (r=0.74) and eggs per plant (r=0.626) were correlated with number of dry leaves, which increased under drought stress. Egg masses per plant increased on sugarcane under drought stressed conditions, and were highly correlated with several free amino acids in sugarcane leaves essential for insect growth and development. Rice leaves, despite being less attractive for oviposition, had higher levels of free amino acids than sugarcane. The more resistant but more attractive rice cultivar XL8 had higher levels of several free amino acids than the susceptible Cocodrie. The association of host plant characteristics to oviposition preference is discussed.