Impact of Catolaccus grandis (Hymenoptera: Pteromalidae) field releases on cotton boll weevil in the Huasteca region of Mexico

摘要

We established boll weevil cohorts in check and release fields and constructed life tables to assess the mortality of boll weevil immatures assignable to Catolaccus grandis (Burks) and other agents. Field sites in Mexico were at Estacion Cuauhtemoc, Tamaulipas and Ebano, San Luis Potosi during late summer of 1999. Results from the release sites indicate that Catolaccus grandis was the main mortality factor of boll weevil, primarily of third instar larvae. Seasonal average mortality of third instars was higher at the Cuauhtemoc release plot (72.4 percent) than at the Ebano release plot (64.3 percent), as was mortality rate from egg to adult (86.1 percent vs. 72.5 percent). However, mortality due to C. grandis parasitism was much lower at Cuauhtemoc than that recorded at Ebano during the crucial early period of boll weevil infestation and establishment, and the effect of the parasitoids was not sufficient to prevent high damage in the release plot at Cuauhtemoc). In contrast, the higher mortality occurring at Ebano during the early infestation period (> 70 percent) may have resulted in a slower population increase and lower overall densities of boll weevil and percent damaged fruit. At Ebano, satisfactory control of boll weevil was observed in the release field while the check required 11 insecticide applications for boll weevil control.