The author carried out some experiments, on the effectiveness of three systemic insecticides (Pestox 3, Systox, Sodium selenate) by soil and foliage application upon the citrus red mite (Metatetranychus citri MCG.), and toxicity of Pestox 3 and Systox to the 7-spotted ladybird (Coccinella septempunctata bnuckii MULSANT). Results obtained are summarized as follows.
1. When three systemic insecticides were wat-ered with water solution on potted Yuzu plant for control citrus red mite, Pestox was most effecti-ve, and the residual action of from 0.075 to 0.15 per cent water solution of this material was con-tinued for 3 months or more after the treatment. Systox was less effective than the Pestox 3, and the residual effect was lost after 11 or 12 weeks. Sodium selenate was little or no effect. The foliage treatments of Pestox 3 and Systox were less effective than their soil treatments.
2. When Pestox 3 and Systox were applied to the fo lige on yo ng Citrus tree in field, both Pestox 3 and Systox gave good control of the citrus red mite, and 0.075 per cent water solution of each material maintaining control for a peiriod of 6 or more weeks after treatment even under condition of heavily infestation of mites.
3. Pestox 3 was nontoxic to the 7-spotted ladybird (Coccinella septempunctata bnuckii MULSANT), but Systox was found highly toxic.

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1.茶葉が凍霜害を被つた1953年と,凍霜害を受けなかつた1952年とにおけるチャハタニの生息密度の比較を行つた。
2.1952年は凍霜害は皆無であつたが,1953年には4月13,15,17,18,24,25日の6回降霜があり,調査園に多大の被害を生じた。
3.チャハダニの生息密度は,4月中は両年間に大差なかつたが,1953年の新葉には1952年より署しく多くのダニが寄生し,摘採以降の成葉でも高い密度を維持した。
4.1953年の新葉にはチャハダニの成虫が早く移動し,そのため成虫,卵ともに1952年の新葉への寄生数よりも著しく多かつた。
5.凍霜害後のチャハダニ防除対策の一つとしてダニのstageについて考察した。
この報告の一部は1954年3月の茶業技術研究発表会において,"晩霜後の観察の一知見"として発表した。

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As shown in previous report, our experiments clearly indicated that plant surfaces were covered very extensively by using the water-dust and mist-dust mixed application methods.
But in those experiments, we felt uneasy about effects of injury of applicated chemicals by the reason that covered surfaces were too extensive for plants.
So, the injuries of applicated chemicals for the Japanese pear, the cabbage and the yam were investigated in the field experiments. And the results of those were as follows;
(1) On the Japanese pear, when mixed chemicals of Bordeaux mixture and BHC dusts were applicated, those injuries were not occurred. But we found injury on the leaves only in the case of Folidol for the dusts.
(2) On the cabbage, injury of applicated chemicals was not found at all. And in the mist-dust mixed application plots the damages by insects and diseases were less than those in the water-dust mixed application plot.
(3) On the yam, injuries of applicated chemicals were not also occurred. The efficiencies of application work by mixed applicators were higher than those by power sprayers.
(4) It can generally be said that we need not care about chemicals injury in using the water-dust and mist-dust mixed application methods.
The working efficiency and pest control effects of these new application methods were good.

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一番茶期におけるカンザワハダニ(チャハダニ)の加害習性について記した。
1.古葉での習性
一番茶期の古葉におけるハダニの生息密度は一般に発芽期から摘採期に向かつて増加する。さらにハダニは茶芽の生育と並行して茶樹の下部から頂部に,内面から表面の茶葉に移動する。
2.茶芽における習性
ハダニが古葉から新芽に移動を開始するのは茶芽摘採の約2～3週間前で,その後も移動を継続する。古葉から新芽への移動はほとんどが成ダニと若ダニによつて行なわれる。摘採期の茶芽では茶樹の頂部と下部とで寄生数に大差がない。茶芽のうちでは下位の葉に多い。被害は茶樹での位置,茶芽の開葉数とは一定の関係はみられないが,茶芽では下位の葉の被害が大きい。一番茶摘採後の新成葉への寄生は異常なほど多い。
3.伝播に関する習性
本虫は風で多数が飛散する。その時期は4～6月で,ほ場の生息密度と並行的である。風で飛散するのはほとんどが成ダニと若ダニである。

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