R. F. L. Mau and L. R. Gusukuma-Minuto
University of Hawaii
Dept. of Entomology
3050 Maile Way, Rm. 310
Honolulu, HI 96822
Phone: (808) 956-7063
Mike McLean
Dole Corporation
Whitmore Village, HI
Jay Pearson
United Hort. Supply
96-1345 Waihona St.
Pearl City, HI 96782

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.