Effect of diazinon fine granule on rice stem borer, Chilo suppressalis Walker

• Published in: Kyushu Plant Protection Research Vol. 17; pp. 120a - 122
• Main Authors: NAGATA, Toru, MAEDA, Yoichi, Pinit, NILPANIT, MORIYA, Shigeo
• Format: Journal Article
• Language: Japanese
• Published: The Association for Plant Protection of Kyushu 1971
• ISSN: 0385-6410; 1884-0035
• DOI: 10.4241/kyubyochu.17.120a

In a field trial of small scale, the effect of fine granule of diazinon, 5% a. i., 100-300 micron in diameter, was investigated against rice stem borer with special references to the application method and the presence of irrigation water in the paddy field. The fine granule was applied at a rate of 40kg (a. i. 2kg) per ha (1) from the top of plant with irrigation water, (2) from the top at dried condition (3) on the soil surface at dried condition. Water supply in (2) and (3) was not made 6 days before and after the application of granule. The moisture content of soil just before the application was about 24%. Rice stem borer was innoculated by fixing egg-masses on paper to leaf sheath of rice plant. Twenty five egg-masses, composed of ca. 50 eggs each, were set for one plot. The infestation was made at two seperate times, 7 days before and just before the application. In the former, eggs at black head stage were set, so that the hatched larvae were to have bored into rice stem 4 to 5 days before the application. In the latter, eggs at middle stage were used, so that the boring of larvae was to occur after the application. When the fine granule was applied from the top of plant already infested, it showed satisfactory control effect both at irrigated and dried condition. Larvae were completely killed and number of injured stem reduced significantly. On the contrary, the granule applied on the soil surface of dried field was less effective. When the granule was applied before hatching of the borer, no reduction of injured stems was found, suggesting that the rice plant could not be protected from ipfestation by hatched larvae. However, at the plots where the granule was applied from the top of plant, mortality of larvae found in the stems was more than 90% and the hatchability of innoculated eggs was also reduced apparently. These results suggest that the insecticidal effect of diazinon fine granule is mainly attributed to the action of fine granule particles attached to the plant but less to the active ingredient penetrated or absorbed through irrigation water. The eggs and larvae could be partly affected through other actions, such as, vaporized ingredient.