South China Agricultural University, Guangzhou, Guangdong, China.
Pest Manag Sci. 2018 Jan;74(1):225-233. doi: 10.1002/ps.4704. Epub 2017 Sep 26.
The two-spotted spider mite, Tetranychus urticae Koch is an important pest of cotton. We investigated the efficacy of dimethoate in controlling T. urticae by drip irrigation. Greenhouse and field experiments were carried out to determine the efficacy of dimethoate to T. urticae and the absorption and distribution of dimethoate in cotton.
Greenhouse results showed that cotton leaves received higher amounts of dimethoate compared with cotton roots and stems, with higher amounts in young leaves compared with old leaves and cotyledon having the lowest amounts among leaves. Field results showed the efficacy of dimethoate to T. urticae by drip irrigation varied by volume of dripping water, soil pH and dimethoate dosage. Dimethoate applied at 3.00 kg ha with 200 m ha water at weak acidic soil pH (5.70-6.70) through drip irrigation can obtain satisfactory control efficacy (81.49%, 7 days) to T. urticae, without negatively impacting on its natural enemy Neoseiulus cucumeris. The residue of dimethoate in all cotton seed samples were not detectable.
These results demonstrate the effectiveness of applying dimethoate by drip irrigation for control of T. urticae on cotton. This knowledge could aid in the applicability of dimethoate by drip irrigation for field management of T. urticae populations. © 2017 Society of Chemical Industry.
二斑叶螨（Tetranychus urticae Koch）是棉花的重要害虫。我们研究了乐果通过滴灌防治二斑叶螨的效果。在温室和田间进行了试验，以确定乐果对二斑叶螨的防治效果以及乐果在棉花中的吸收和分布。
温室结果表明，与棉根和茎相比，棉叶接收了更多的乐果，与老叶相比，嫩叶接收了更多的乐果，子叶中的乐果含量最低。田间结果表明，通过滴灌施药量、滴水量、土壤 pH 值均影响乐果对二斑叶螨的防治效果。在弱酸性土壤 pH 值（5.70-6.70）下，通过滴灌施用量为 3.00 公斤/公顷、水量 200 立方米/公顷的乐果，对二斑叶螨具有满意的防治效果（7 天后 81.49%），且对其天敌尼氏钝绥螨没有负面影响。所有棉花种子样本中均未检测到乐果残留。
这些结果表明，通过滴灌施用乐果防治棉花上的二斑叶螨是有效的。这些知识可以帮助滴灌施用乐果控制二斑叶螨田间种群。 © 2017 化学工业协会。
