Resource Information

Control of Green Scale on Cape Jasmine with Imidacloprid, Hawaii, 1993  

By: A. H. Hara, T. Y. Hata and B.K.S. Hu

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

HOST: Cape Jasmine: Gardenia jasminoides Ellis
TARGETED PEST: Green scale: Coccus Viridis

Efficacy trials were conducted from 27 Oct through 23 Dec 1993 at the University of Hawaii at Manoa, Waiakea Experiment Station in Hilo, Hawaii. One year old established plants, approximately 2 ft tall, growing in 9 by 10 inch polyethylene bags under a fiberglass greenhouse were used in this study. Treatments consisted of 4 replicates with 2 plants per replicate. Treatments were evaluated by taking visual counts on the number of live and dead scales from three leaves selected at random from the bottom, center and top of each plant on 27 Oct (pretreatment), and 12, 18, and 23 Nov. To determine efficacy against crawlers and eggs, counts were taken on 30 Nov, and 6, 16, and 23 Dec using a dissecting microscope. Imidacloprid 0.62G (NTN 33893 0.62 G) was applied once at 0.009 g AI per bag (0.001 g AI / inch diameter) on 28 Oct 93 and watered immediately after treatment. Percentage mortality was calculated using the mean number of live and dead scales from two leaves (one per plant) from each location. Percentages were transformed to arcsine sqrt and subjected to ttest. Back transformed means are presented. Plants were also observed weekly for phytotoxicity.

There was no significant difference in mortality between treatments before insecticide application. Mortality of treated nymphs was significantly higher than the control 2 wks. after insecticide application. Significant differences in adult mortality occurred after 4 wks. After 6 wks., imidacloprid completely eliminated nymphs and crawlers and > 99.7 % of parthenogenetic adults. Eggs were not present in all reps, therefore data were not analyzed. Imidacloprid remained effective with a single application until the experiment was terminated on 23 Dec because of fungal infection affecting the control mortality. Phytotoxicity was not observed.

16 Dec 1993

    % mortality    
  Adult** Nymph** Crawler** Total**
Bottom leaf        
NTN 100.0 + 0.0a 99.4 + 0.1 99.8 + 0.2 99.5 + 0.1
Control 0.3 + 0.3 7.3 + 0.0 0.9 + 0.9 6.9 + 0.1
Center leaf        
NTN 100.0 + 0.0 99.6 + 0.1 99.9 + 0.0 99.7 + 0.0
Control 1.4 + 0.5 8.4 + 0.2 4.7 + 0.8 8.2 + 0.1
Top leaf        
NTN 100.0 + 0.0 99.3 + 0.2 100.0 + 0.0 99.4 + 0.2
Control 4.3 + 0.2 7.3 + 0.0 2.9 + 1.0 6.7 + 0.1

Data subjected to t test. ** significant at P < 0.01, respectively.
aSEM for mean of percentages.


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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: NTN 33893 0.62 G
Manufacturer’s Name: Miles Inc.
Address: P.O. Box 4913, 8400 Hawthorn Road, Kansas City, MO 64120
Composition: imidacloprid 0.62G