Control of the Rhodesgrass scale, Antonina graminis Maskell, Injurious to the Turfgrass
1987 Volume 16 Issue 1 Pages 13-20
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1987 Volume 16 Issue 1 Pages 13-20
The author studied the economical and rational control of the foreign insect, Rhodesgrass scales (Antonina graminis Maskell) which causes injury to turfgrass. We investigated the distribution of this insect in the Shikoku area. Contact-type and systemic-type insecticides were tested on the Rhodesgrass scale. The study is summarized below. (1) From among the eight golf courses located in Kouchi Prefecture, the Rhodesgrass scales was discoverd in seven of them. The dissemination of the insect originates at nurseries and is transferee to the golf course when turfgrass is transplanted. We suggest that insecticides be sprayed on the turfgrass before it is transplanted to the golf course. Thus, it is necessary to control this insect at nurseries.
(2) Various insecticides were spryed on the first nymph of the second generation of Rhodesgrass scale on the 31st of July, 1984, and again on the 11th of August to different location at the Tosa Country Club.
The best results of Rhodesgrass scale control on the 31st of July (88.5 %), and on the 11th August (79.9%) were achieved with a 45% emulsion formulation of Supracide (3l / m2, 1000 times) . This insect is perthenogetic and multiplies by ovoviviparity. The adult inseects oviposit about 200 nympha, and has 2 life cycles per year. Therefore, it seems that the high level control of the density of Rhodesgrass scales is not severaly affected in spit of the 45% EC Supracide.
(3) When we used 24% EC Birlane (3l/m2, 1000 times) the success rate was 66.2% on July 31st and 63.0% on August 11th.
The active ingredient was composed of 50% EC Supracide and 24% EC Birlane. Therefore, the active ingredient of EC Birlane is about 50% less than that of the Supracide. If we spray Rhodesgrass scales with EC Birlane (31/m2, 500 times), we get better control results.
The control results of 40% EC Diazinon (1l/m2, 1000 times) was 35.1% on August 11th. Diazinon has low level control. Because the active ingredient of Diazinon becomes a gas on turfgrass, therefore it seems that the residue term of Diazinon is short.
(4) The control, applied on different application days (July 31st and August 11th), should produce the almost same trend in results.
We presumed that the density of Rhodesgrass scales was greater in the second generation than in the first generation. The developmental stage of the Rhodesgrass scales was not equal and the egg-stage of these inects is always present.
(5) The application ratio of systemic insecticide (Azodrin granular, SDI-83Y granular) was 9 -10kg/10a. This rate was for the control of the larva of white grubs. We sprayed the Rhodesgrass scales with this application ratio on July 27th 1985, but this insecticide was not very effective.
In addition, a double application, once on July 27th and again on August 19th, was not effective either.
(6) A better control, 86.2%, was achieved with SDI-83Y (3%) granular (50g/m2) . We think that a higher ratio of granular (50 g/m2) must be applied to inhibit the spread of Rhodesgrass scales.
(7) Rhodesgrass scales has sucking mouth parts, therefore ; the emulsion type (Birlane, Supracide) are more effective than the granular type (Azodrin, SDI-83Y) . And, it is thought that the spraying of systemic insecticides after cutting the top of turfgrass is suitable to increase rapidly the concentration of insecticide in turfgrsas plant. Because, the Rhodesgrass scales is controled when it sucks the plant that contains systemic insecticies.
(8) On March 7th 1985, we burned the surface of turfgrass in the golf course rough at the Tosa C. G., when this turfgrass was moist. In spite of moisture, this method was comparatively effective (56.9%) .
It is thought that during the dry season, from November to January, the bottom of the turfgrass would be dry, so we should get better results.
