(27(1):1-11)REEVALUATION OF CHEMICALS FOR THE BROWN PLANTHOPPER CONTROL IN TAIWAN

本試驗係省農廳委由嘉義農業試驗分所及臺中區農業改良場，將政府歷年來推薦於水飛蝨防治用藥劑於相同環境下進行藥效比較試驗。試驗分別於民國64年及66年稻褐兩次舉行。試驗結果表示，目前值物保護手冊所列用於防治褐飛蝨藥劑對褐飛蝨之防治效果差異很大，同時在兩試驗區防治效果較優者，按其優劣順位為(1)乳劑類：40.64% Furadan FW, 40% Hokbal EC, 20% MIPC EC; (2)可濕性粉劑類：75% Furadan WP, 50% Unden WP, 50% MIPC WP, 75% Orthene WP及40% BPMC WP; (3)粉劑類1% Unden D, 3.5% Ofunak-M D.及(4)粒劑頓：3% Furadan G, 5% Unden G., 5% Geofos G.及6% Mipspanon G.等。上述藥劑中，在第二期稻作期間，使用乳劑，可濕性粉劑或粉劑通常需要施藥2至3次方足以抑制褐飛蝨之增殖為害，而粒劑則通常使用1~2次即可獲得相同的防治效果。 A total of 35 insecticides have been registered with the government for the brown planthopper control since last 10 years. Recently, Some of these chemicals have been found by no means satisfactory to control the brown planthopper by the extension workers and farmers. In order to provide a basis for the farmers to select more effective insecticides from among these compounds, a series of experiments were then conducted in Chiayi and Taichung districts simultaneously to reevaluate those chemicals under field conditions in 1975 and 1977. The result of these experiments are sumarized as follows: The effect among chemicals tested on the brown planthopper control differed greatly. The following chemicals namely 40.64% Furadan FW., 40% Hokbal EC., 20%MIPC EC., 70%Furadan WP., 50 %Unden WP., 50% MIPC WP., 75% Orthene WP., 40% BPMC W P., 1% Unden D., 3.5% Of unak-M D., 3% Furadan G., 5% Unden G., 6% Mipspanon G. and 5% Geofos G. showed better effect on control of the brownplanthopper than the others both in Taichung and Chiayi experiments. The granules in general had longer residual effect than foliar applications and one to two applications during booting to heading stage controlled the brown planthopper satisfactorily throughout a crop. On the other hand, to obtain a better fesult from the foliar application, including emulsions (or solutions ) , wettabe (or soluble) powders and dusts requisted 2-3 or more applications per crop due to the shorter residual effect and the difficulty to deposite the chemicals efficiently in the habitat of the hoppers especially during the middle or later stages of plant growth. Therefore continous applications usually were needed while the application made in case of the population of the brown planthopper in great increase. Based on the pattern of population growth of the brown planthopper in Taiwan, the rice plant can be protected from a severe damage of the insect during maturing stage if the brown planthopper can be controlled satisfactorily at maxinum nymphal stage of 2nd generation after its immigration into paddy field or at the end of booting stage of rice