Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA, USA.
Pest Manag Sci. 2014 Feb;70(2):338-44. doi: 10.1002/ps.3570. Epub 2013 Jul 29.
The systemic insecticides chlorantraniliprole (CAP) and thiamethoxam (TMX), applied to rice as seed treatments, may affect multiple life stages of the rice water weevil, Lissorhoptrus oryzophilus. Effects of CAP and TMX on adult survival, egg-laying and first- and late-instar survivals were determined by infesting plants treated as seeds with different rates of insecticides. The biological activity was related to insecticidal concentrations in leaves, shoots and roots.
CAP did not affect adult survival but decreased egg numbers and reduced the survival of the first and late instars. The greatest reduction in weevil population occurred in late instars feeding on roots. In contrast, TMX reduced adult survival and egg and larval numbers. The high biological activity of CAP on root-feeding stages was consistent with the accumulation of CAP in roots, whereas in TMX-treated plants the high activity on adults correlated with high concentrations of TMX in leaves and stems.
The differential activity of insecticides on adults suggests poor inherent potency of CAP as an adulticide and/or its limited systemicity in foliage. The distribution of insecticide in specific plant parts can be attributed to the different physicochemical properties of CAP and TMX. The field implications of this research on management of L. oryzophilus are discussed.
作为种子处理剂施用于水稻的系统性杀虫剂氯虫苯甲酰胺（CAP）和噻虫嗪（TMX）可能会影响稻水象甲（Lissorhoptrus oryzophilus）的多个生活阶段。通过用不同剂量的杀虫剂处理种子来侵染植物，确定了 CAP 和 TMX 对成虫存活率、产卵和 1 龄和 2 龄幼虫存活率的影响。生物活性与叶片、茎和根中的杀虫浓度有关。
CAP 不影响成虫存活率，但会降低产卵数，并降低 1 龄和 2 龄幼虫的存活率。在以根为食的晚期若虫中，象甲种群数量减少最多。相比之下，TMX 降低了成虫存活率和产卵量以及幼虫数量。CAP 对根食期具有高生物活性与 CAP 在根中的积累一致，而在 TMX 处理的植物中，叶片和茎中 TMX 浓度高与成虫的高活性相关。
杀虫剂对成虫的不同活性表明 CAP 作为成虫杀虫剂的固有效力较差，或者其在叶片中的系统传播性有限。杀虫剂在特定植物部位的分布归因于 CAP 和 TMX 的不同物理化学性质。该研究对稻水象甲管理的田间意义进行了讨论。
