Abstract
Barked pine logs of 1 meter length were used to test toxicants which were made of some of the following components: fenitrothion, fenthion, ethylene dibromide, and kerosene (solvent). Each toxicant, which was dissolved at different concentrations in kerosene, was sprayed on the logs which included overwintering larvae of Monochamus alternatus HOPE in pupal cells, at the rate of 600ml per square meter in January. In August, the logs were cut, and the mortality (non-emerging percent of M. alternatus) was recorded and the toxicity (LC50 concentration of fenitrothion, or fenthion-, or LC90) was obtained by using probit analysis. The toxicity (LC50) was 0.094 percent (fenitrothion solution), 0.078 percent (fenitrothion-ethylene dibromide solution), 0.559 percent (fenthion solution) or 0.543 percent (fenthion-ethylene dibromide solution), and LC90 was 0.332 percent (fenitrothion solution), 0.294 percent (fenitrothion-ethylene dibromide solution), 1.449 percent (fenthion solution) or 1.064 percent (fenthion-ethylene dibromide solution). However, there was no significant difference in the toxicity between fenitrothion and fenitrothion-ethylene dibromide solution or between fenthion and fenthion-ethylene dibromide solution, judging from 0.95 fiducial intervals. These results indicate no significant difference in the toxicity between organophosphorus toxicants and ethylene dibromide, alone and in combination, to M. alternatus in pupal cells.
