Resource Information

Residual Activity of Insecticides on Dendrobium for Control of Orchid Weevils, 1993  

By: A. H. Hara and T. Y. Hata

Beaumont Agri. Res. Center, University of Hawaii-Manoa, 461 W. Lanikaula St., Hilo, Hawaii 96720, Phone (808) 935-2885

HOST: Dendrobium Orchid: Dendrobium 'Uniwai Supreme', 'Uniwai Pearl'
TARGETED PEST: Orchid weevil: Orchidophilus aterrimus(Waterhouse)

Bioassay tests were conducted from 10 Mar through 8 Apr 1993 (study 1) and 31 Aug through 22 Sep 1993 (study 2) at the University of Hawaii at Manoa, Waiakea Experiment Station in Hilo, HI. Established plants 'Uniwai Supreme' (study 1), and 'Uniwai Pearl' (study 2) growing in 0.5 inch crushed basalt rock under a Conley cold frame greenhouse (6 mil. clear FVG 3HLFI polyethylene film covering) were used in this study. Insecticides were applied once at 1,375 liters/ha using a compressed air sprayer with a 8004 Teejet nozzle at 40 psi. Sixteen leaves per treatment, 4 leaves per replicate, were removed weekly from the plant and placed into 12.0 x 10.5 cm unwaxed paper containers. Ten orchid weevils field collected on bamboo orchids, Arundina graminifolia (D. Don) Hochr. was added to each replicate and covered with organdy. In study 1, leaves were bioassayed 7, 14, and 21 d after treatment and mortality and the number of feeding marks (injury) assessed 5 d after exposure. In study 2, leaves were bioassayed 7 and 14 d after treatment and mortality and injury assessed 2 d after exposure.

In study 1, all treatments had significantly higher mortality than the control. Talstar was most effective, killing all weevils at 7, 14, and 21 days after treatment (DAT) within 5 days after exposure (DAE). Tempo, and Tame caused < 24% mortality at 21 DAT. There was no significant difference between Tempo and Tame, 14 and 21 DAT. Immediately after exposure, orchid weevils in all insecticide treatments were observed crawling on the top of the container. This behavior was not observed in the control and apparently was a repellent action of the insecticide. In addition, all treated leaves had significantly less feeding injury 5 DAE as compared to the control. In study 2, Talstar had significantly higher mortality than Pageant and the control. There was no significant difference in feeding injury between Talstar and Pageant.

Study1 (g) AI/liter 7 DATa
% mort.
feeding injury 14 DATa
% mort.
feeding injury 21 DATa
% mort.
feeding injury
Talstar F 0.20 100.0a*** 0.0b*** 100.0a*** 0.0b*** 100.0a*** 0.3b**
Tame 2.4EC 0.20 45.0c 28.8b 39.8b 58.3b 5.7bc 102.3b
Tempo 2EC 0.04 78.4b 8.8b 34.6b 51.0b 24.0b 41.3b
Control -- 0.0d 143.0a 0.0c 222.5a 0.0c 224.3a
Study 2 (g) AI/liter 7 DATa
% mort.
feeding injury 14 DATa
% mort.
feeding injury    
Talstar F 0.20 92.5a*** 1.0b** 92.5a*** 2.5b*    
Pageant DF 0.60 2.6b 48.3ab 2.1b 50.3ab    
Control -- 0.0b 108.5a 0.0b 100.5a    

Percentage mortality transformed to arcsine(sqrt) before analysis. NS, *, **, ***, not significant or significant by anova P< 0.05, 0.01, 0.0001, respectively. Means followed by the same letter in a column are not significantly different by Scheffe's multiple comparison procedure.
aDays after treatment. Mortality and feeding injury assessed 5 d and 2 d after exposure in studies 1 and 2, respectively.


Use pesticides safely. Follow the pesticide label. Consult with the Cooperative Extension Service or the Hawai'i State Department of Agriculture for authorized special local need registrations or additional information. The user is responsible for the proper use, application, storage, and disposal of pesticides.

Reference to a company or product name does not imply approval or recommendation of the product by the College of Tropical Agriculture and Human Resources, Cooperative Extension Service University of Hawaii, or the United State Department of Agriculture and does not imply its approval to the exclusion of other products that may be suitable. All materials should be used in accordance with label instructions or manufacturer's directions.

Product Name: Pageant DF
Manufacturer's Name: DowElanco
Address: 9002 Purdue Rd., Indianapolis, IN 46268-1189
Composition: chlorpyrifos 50%

Product Name: Talstar Flowable
Manufacturer's Name: FMC Corp.
Address: 2000 Market Street, Philadelphia, PA 19103
Composition: bifenthrin 0.67 lb active per gallon

Product Name: Tame 2.4EC
Manufacturer's Name: Valent U.S.A. Corporation
Address: 1333 NO. California St., Walnut Creek, CA 94598
Composition: fenpropathrin 2.4 lb active per gallon

Product Name: Tempo 2EC
Manufacturer's Name: Miles Inc.
Address: P.O. Box 4913, 8400 Hawthorn Road, Kansas City, MO 64120
Composition: cyfluthrin 2.0 lb active per gallon