Monday, December 10, 2007 - 8:17 AM
0331

Parasitization of sugarcane borer (Lepidoptera: Crambidae) by Cotesia flavipes (Hymenoptera: Braconidae) on rice

Jiale Lv, lvjiale@tamu.edu1, Lloyd T. (Ted) Wilson, lt-wilson@aesrg.tamu.edu1, and Julien M. Beuzelin, jbeuzelin@agcenter.lsu.edu2. (1) Texas A&M University System, Agricultural Research and Extension Center at Beaumont, 1509 Aggie Dr, Beaumont, TX, (2) Louisiana State University Agricultural Center, 402 Life Sciences Bldg, Baton Rouge, LA

A field experiment was conducted during 2005 and 2006, to investigate sugarcane borer larval development duration and survival, each as affected by three rice cultivars (Cocodrie, Francis and Jefferson) and three crop growth stages (the 3rd tiller stage, the panicle differentiation stage, and the heading stage. The sugarcane borer larval development duration in rice was shorter at heading (514.4 89.0 DD) than either at the 3rd tiller stage (591.0 49.4 DD) and at panicle differentiation (608.3 73.0 DD). The survival rate of sugarcane borer larvae was higher when infested at the 3rd tiller stage (0.160), than either at panicle differentiation (0.051) or at heading (0.056).

Cotesia flavipes adults were released into field cages enclosing sugarcane borer infested rice plots, to investigate parasitization of sugarcane borer by C. flavipes, C. flavipes fecundity, and sex ratio. The C. flavipes release densities was 8 females per m2 in 2005 and 40 females per m2 in 2006.The parasitization rate were the highest at the 3rd tiller stage (8.2% in 2005, 17.6% in 2006), followed by the panicle differentiation stage (6.1%, 8.7%) and the heading stage (1.7%, 3.9%). The effective search rate of was 0.0018 m2 ground area per day per parasitoid. The number of C. flavipes progeny produced per parasitized larvae was 27.9 19.1, with a 3.5 :1 female/male sex ratio.

A cohort based age structured model was developed to determine the rates and timings of releases of C. flavipes required to provide economic control of the sugarcane borer.



Species 1: Lepidoptera Crambidae Diatraea saccharalis (sugarcane borer)
Species 2: Hymenoptera Braconidae Cotesia flavipes