Chemical Control of Rice Stem Maggot and Rice Leaf Miner
スポンサーリンク
概要
- 論文の詳細を見る
In 1956 collective applications of dieldrin 4% and EPN 1.5% dusts were undertaken to evaluate their effectiveness for the control of rice stem maggot, <I>Chlorops oryzae</I> MATSUMURA, and rice stem borer, <I>Chilo suppressalis</I> WALKER, and to determine the degree of possible fish hazard of dieldrin inside the paddy fields and at the down streams.<BR>The experimental area was 24 acres which were exactly divided into 3 plots; dieldrin, EPN, and check. One plot consists of 32 pieces of field. The chemicals were applied with auto-duster at the rate of 30 lbs. per acre on all parts inside the plot including weeds on the foot paths or road shoulders from which fly of rice stem maggot migrated into the paddy fields. The date of application was June 30 just falling on the peak of cvipositon of rice stem maggot and the infant larval stage of rice stem borer.<BR>Results obtained are summarized as follows:<BR>(1) A remarkable reduction in numbers of Diptercus adults including the rice stem maggot was observed in dusted plots especially at the center of them.<BR>(2) Significant reduction in numbers of eggs and injured heads by the maggot were also given in the dusted plots, counting the numbers of the injured heads one-third at the center and a half at the border comparing those of the check.<BR>(3) In both dusted plots the number of dead stems caused by the borer was reduced to one-third. The fact that the average body weight of larvae collected was heavier in dusting plots than in the check, showed that the newly hatched and younger instar larvae within stems were killed by dusting. It was proved that both maggot and borer of the first generation were controlled dually by one application of these chemicals at the end of June.<BR>(4) Additional application of EPN 1.5% dust on August 15 (5 days after the peak of moth emergence) gave very satisfactory control of the second generation stem borer. And higher yields were also gained in those dusting plots.<BR>(5) The toxicity on fish and concentration of dieldrin in water were investigated in the dusting area and in its neighboring irrigation brooks for two weeks after application. The degree of toxicity seems to be influenced by the environmental conditions such as climatic conditions, flow of irrigation water, velocity and capacity of current water in the brooks, etc. Directly after the application the concentration of dieldrin in water varied from 0.6 to 1.5 p.p.m. and the tested small carp died within 8 hours inside the dusted paddy fields. By the supply of fresh water fish were no more killed in any paddy fields after 8 days. At the drainage way the maximum concentration of dieldrin detected in water was 0.4 p. p. m., and the toxicity continued for about 10 days after application. When a great quantity of water ran in the irrigation brooks. no toxicity on fish was observed.<BR>(6) As a rule, no economic hazard on fish might be occurred in the recommended usage of dieldrin dust for the control of maggot.
- 北日本病害虫研究会の論文
北日本病害虫研究会 | 論文
- 露地夏秋キュウリにおけるホモプシス根腐病の発生
- チョウセンニンジンに発生した茎腐れ症状
- 福島県で発生したダイコン根こぶ病について
- 農業におけるバイオテクノロジ-と作物保護
- ブドウ根頭がんしゅ病菌北海道分離株のPCR法による検出