Resource Information

     
Control of Orchid Weevils on Dendrobium, Hawaii, 1993  
     

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

Beaumont Agri. Res. Center, University of Hawaii-Manoa, 461 W. Lanikaula St., Hilo, Hawaii 96720, Phone (808) 935-2885, Fax (808) 969-7923

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


EXPERIMENTAL PROCEDURE
Bioassay tests were conducted from 10 Mar. through 8 Apr. 1993 at the University of Hawaii at Manoa, Waiakea Experiment Station in Hilo, HI. Established plants growing in 1.27 cm 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 to runoff (approximately 1,375 liters/ha) using a compressed air sprayer with a 8004 Teejet nozzle at 276 KPa. Seven, 14 and 21 days after treatment (DAT), 16 leaves per treatment, 4 leaves per rep, were removed from the plant and placed into 12.0 x 10.5 cm unwaxed paper containers. Ten orchid weevils collected on bamboo orchids, Arundina graminifolia (D. Don) Hochr. was added to each replicate and covered with organdy. Mortality and the number of feeding marks were assessed 1, 5, and 8 days after days after exposure (DAE).

RESULTS
All treatments had significantly higher mortality than the control. Talstar was most effective, killing all weevils at 7, 14, and 21DAT within 5 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 response to the insecticide. In addition, all treated leaves had significantly less feeding injury 5 DAE as compared to the control.

Table 1. Percentage mortality of orchid weevils and feeding injury 1, 5 and 8 days after exposure to residue on leaves harvested weekly after one insecticide application.

7DATa (g) AI/liter 1 DAEb Injury 5 DAE Injury 8 DAE Injury
Talstar F 0.20 92.5(a)*** 11.5(b)** 100.0(a)*** 0.0(b)*** 100.0(a)*** 0.0(b)***
Tame 2.4EC 0.20 0.6(b) 37.5(a) 45.0(c) 28.8(b) 60.6(b) 24.5(b)
Tempo 2EC 0.04 13.5(b) 9.3(b) 78.4(b) 8.8(b) 94.7(a) 1.0(b)
Control -- 0.0(b) 33.3(a) 0.0(d) 143.0(a) 0.0(c) 131.5(a)
               
14DAT (g) AI/liter 1 DAE Injury 5 DAE Injury 8 DAE Injury
Talstar F 0.20 98.7(a)*** 14.8(b)** 100.0(a)*** 0.0(b)*** 100.0(a)*** 0.0(aNS)
Tame 2.4EC 0.20 2.6(b) 31.3(b) 39.8(b) 58.3(b) 44.9(b) 30.3(a)
Tempo 2EC 0.04 0.6(b) 42.5(ab) 34.6(b) 51.0(b) 39.8(b) 15.5(a)
Control -- 0.0(b) 64.8(a) 0.0(c) 222.5(a) 0.0(c) 50.5(a)
               
21DAT (g) AI/liter 1 DAE Injury 5 DAE Injury 8 DAE Injury
Talstar F 0.20 72.4(a)*** 13.5(b)** 100.0(a)*** 0.3(b)** 100.0(a)*** 0.0(c)**
Tame 2.4EC 0.20 0.0(b) 47.8(a) 5.7(bc) 102.3(b) 5.7(bc) 113.8(ab)
Tempo 2EC 0.04 2.6(b) 55.3(a) 24.0(b) 41.3(b) 23.3(b) 42.8(bc)
Control -- 0.0(b) 36.8(ab) 0.0(c) 224.3(a) 0.0(c) 165.8(a)

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.
(a) Days after treatment.
(b) Days after exposure.

PRODUCT INFORMATION

PRECAUTIONARY STATEMENT
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.

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