University of Missouri, Division of Plant Sciences, P.O. Box 160, Portageville, MO 63873, USA.
J Insect Sci. 2013;13:62. doi: 10.1673/031.013.6201.
The rice water weevil, Lissorhoptrus oryzophilus (Kuschel) (Coleoptera: Curculionidae), is a semi-aquatic pest of rice and is the most destructive insect pest of rice in the United States. Adults oviposit after floods are established, and greenhouse studies have shown that plants exposed to deep floods have more eggs oviposited in leaf sheaths than plants exposed to a shallow flood. Experiments were conducted in three mid-southern states in the USA to determine if the depth of flooding would impact numbers of L. oryzophilus on rice plants under field conditions. Rice was flooded at depths of approximately 5 or 10 cm in Arkansas in 2007 and 2008 and Louisiana in 2008, and at depths between 0-20 cm in Missouri in 2008. Plants were sampled three and four weeks after floods were established in all locations, and also two weeks after flood in Missouri. On all sampling dates in four experiments over two years and at three field sites, fewer L. oryzophilus larvae were collected from rice in shallow-flooded plots than from deep-flooded plots. The number of L. oryzophilus was reduced by as much as 27% in shallow-flooded plots. However, the reduction in insect numbers did not translate to a significant increase in rice yield. We discuss how shallow floods could be used as a component of an integrated pest management program for L. oryzophilus.
稻水象甲，又名 Kuschel 稻水象甲（鞘翅目：象甲科），是一种半水生的水稻害虫，也是美国水稻上最具破坏性的害虫。成虫在洪水建立后产卵，温室研究表明，与暴露在浅洪水中的植物相比，暴露在深洪水中的植物叶片鞘中产卵更多。在美国三个中南部州进行了实验，以确定在田间条件下，洪水深度是否会影响稻水象甲在水稻植株上的数量。2007 年和 2008 年在阿肯色州以及 2008 年在路易斯安那州，将水稻淹没在约 5 或 10 厘米深的水中，而 2008 年在密苏里州，将水稻淹没在 0-20 厘米深的水中。在所有地点，洪水建立后三到四周以及密苏里州洪水后两周进行了植物采样，在两年四次实验的所有采样日期以及在三个田间地点，与深洪水中的植株相比，浅洪水中的植株上收集到的稻水象甲幼虫更少。在浅洪水中，稻水象甲的数量减少了多达 27%。然而，昆虫数量的减少并没有转化为水稻产量的显著增加。我们讨论了浅洪水如何可以作为稻水象甲综合管理计划的一个组成部分。
