LABORATORY EVALUATIONS OF INSECTICIDES AGAINST CRB ADULTS, 1996:
LABORATORY BIOASSAY
Chinese rose beetle (CRB); Adoretus sinicus Burmeister
Field collected adults of CRB were held in a ventilated cage with an adequate food supply for two days prior to beginning the bioassay. Water based mixtures of each treatment were prepared in glass beakers at 100 GPA. Silwett L-77 at 8.0 oz./100 gal solution was added to each solution to facilitate wetting and each mixture was mixed thoroughly. Treatments were evaluated using the leaf dip method. Taro (Colocasia esculenta) leaves were field collected and held in the refrigerator until they were ready to use. Three leaves were completely immersed in each of the spray mixtures and allowed to air dry. The treated leaves were cut into 5 cm2 pieces and placed into ventilated plastic petri dishes. Five adult CRB were also added to the dish. Each treatment was replicated 10 times. Mortality was assessed at 24-hour intervals. At each assessment, leaf pieces were changed with a fresh leaf piece cut from the remaining treated leaves to assure a fresh food supply.
Carbaryl 50 WP provided excellent control of the CRB adults at both test rates. More than half of the beetles were killed within one day and 80-90% were killed by 3 DAT 1. The two other insecticides were ineffective against CRB adults with percent mortality not significantly different from the untreated check.
__________Mean % mortality__________ |
Test material | Concentration (amt/100 gal) |
1 DAT | 2 DAT | 3 DAT | ||||||||||||
Carbaryl 50 WP | 1.0 lb. | 50.0+8.56a | 84.0+5.81a | 84.0+5.81a | ||||||||||||
Carbaryl 50 WP | 2.0 lb. | 66.0+7.33a | 92.0+3.27a | 94.0+3.06a | ||||||||||||
Diatect | 3.0 lb. | 2.0+2.00b | 4.0+2.67b | 6.0+4.27b | ||||||||||||
Pyrellin EC | 2.0 pt. | 0.0+0.00b | 2.0+2.00b | 2.0+2.00b | ||||||||||||
Untreated check | --- | 4.0+2.67b | 4.0+2.67b | 8.0+3.27b |
Numbers in the same column followed by a different letter are significantly different (P<0.0001 Tukey's studentized range test SAS Institute version, 6.08). Data was subjected to arcsine transformation prior to analysis. Untransformed number are presented.
Trade Composition\Common name | Formulation | name | Source | ||||||||
Carbaryl | WP | carbaryl | Platte Chemical Co. | ||||||||
Diatect | WP | ----- | Diatect International Inc. | ||||||||
Pyrellin | EC | pyrellin | Webb Wright Corp. |