Field experiments were carried out at Henan, Hebei and Hubei to control Helicoverpa armigera and Plutella xylostella with Bt MP-342. MP-342 dust (16000IU/mg) and MP-342 solution (4000IU/ml), produced by Hubei Bt Research and Development Center, were used to prepare Bt sprays for field application. Experimental results showed that the MP-342 dust 500× and 1000× sprays killed the H. armigera 75.0%-95.7% and 72.2%-85.9% respectively in 70 h. The control effect was significantly higher than that of the chemical pesticide treatments. The MP-342 solution 1000× and 2000× sprays reduced the field population of the P. xylostella 98.5% and 88.4% respectively in 48 h.
The effects of 3 herbicides, Glyphosate, Paraquat and Londex at recommended herbicidal rates on the mortality of water hyacinth weevil, Neochetina eichhorniae were tested in both laboratory and field. The hatching rates of the eggs contacted directly with Glyphosate, Parapuat, Londex and water (control) were 83.3%, 93.3%, 92.2% and 95.6%, respectively. When these herbicides were sprayed on the water hyacinth leaves infested with weevil eggs, the hatching rates were 90.0%, 53.4%, 85.6% and 93.6%, respectively. There were no great effects on the mortality of the first instar larvae and pupae of the weevil treated with the herbicides. The eggs oviposited by each female/d treated with Glyphosate, paraquat, londex were 1.14, 0.17, 0.27, the control being 1.13. The survival rate of the adults feed on the leaves sprayed with 3 herbicides and water were 92.5%, 0, 95.0% and 97.5% after 70d, respectively. The order of effect of the 3 herbicides on the weevil was: Paraquat>Londex>Glyphosate.
