Insecticidal activities of an insect growth regulator, tefurubenzuron against the important turfgrass insects

Abstract

Insecticidal activities of an insect growth regulator, tefurubenzuron against the important turfgrass insects, the japanese lawn grass cutworm (LGC), Spodoptera depravata, the bluegrass webworm (BWW), Parapediasia teterrella, the oriental beetle (OB), Blitopertha orientalisand the cupreous chafer (CC), Anomala cuprea, were evaluated by laboratory and field tests.
(1) Laboratory tests
Tefurubenzuron showed high insecticidal activity against larvae of LGC, BWW, OB and CC. Complete death were observed by application of 25 or 50ppm (active ingreditent) of tefurubenzuron, against young or middlestage larvae of the LGC, respectively.
Mortalities of 1st or 2nd instar larvae of the BWW treated by 50ppm of tefurubenzuron were 100%.
Mortalities of 1st or 2nd instar larvae of the OB, and of 2nd instar larvae of the CC, treated by 25 or 50ppm of tefurubenzuron were 90% or much more.
According to the results of this experiments against 2nd instar larvae of the CC, feeding activity of the insects which were poisoned by sublethal dose of tefurubenzuron, were strongly suppressed.
Short-term (4 days) application of tefurubenzuron was also effective against the CC, which may indicated that tefurubenzuron are relatively stable in the insect body, and can be expected sure controlling effects against the beetles.
The speed of action of tefurubenzuron against beetle larvae is much more slow than lepidopterous larvae, and terms enough to complete the toxic action of the chemical were estimated about 15-30days.
(1) Field tests
Results of the field experiment indicated that LGG and BWW were effectively controlled by spraying of diluents, 3000-4000 times of tefurubenzuron 10% emulsifiable conscentrate, at rate of 300ml/m².
It was recognized in a test of the BWW, that the controlling effect of tefurubenzuron came out more slowly than that of an organophosphate insecticide, fenitrothion.