Abstract
In order to select the effective insecticides for control ofGeoblissus hirtulusBurmeister injurious to turfgrass, the insecticidal effect of 15 insecticides was evaluated by laboratory and field tests.
a. From the results of insecticidal tests on adults of this insect by the impregnated filter paper method, cartap showed the greatest effect, followed by salithion, r-BHC, PHC, fenitrothion, fenthion, diazinon, CVP in that order.
b. Concerning the rate of penetration of several insecticides into the soil of sample pots, the liquid form showed higher penetration into the soil than the granular form.
Then, in test data for several liquid formulations, PHC showed the highest soil penetration.
Secondary fenthion showed the higher penetration and cartap showed the lowest.
Further, for penetration of several granule-type formulations into soil owing to differences in the number of waterings, only PHC penetrated to the B soil layer after four waterings. Fenthion and diazinon did not penetrate to the B layer even when the number of waterings increased.
c. Compared with the persistent effect against adults of this insect when 6 insecticides diluted to 1/1000 were sprayed at 41/m2over the turfgrass area, PHC (50% W. P.) showed more thans 30% mortality on the 15th day after spraying. Other insecticides showed less than 30% mortality on the 5th day.
d. It seems to me that control of this insect by pesticides is in the period from the middle of May to early June, because, the peak of adult emergence is the highest in this season and the adults live in shallower soil.
We suggest that PHC (50% W. P.) or fenitrothion (50% E. C.) diluted to 1/1000 be sprayed with the above 41/m2over the involved turfgrass area.
