School of Plant Protection, Yangzhou University, Yangzhou 220059, P.R. China.
J Econ Entomol. 2013 Feb;106(1):196-205. doi: 10.1603/ec12228.
The rice leaffolder, Cnaphalocrocis medinalis Guenee (Lepidoptera: Pyralidae), is a rice pest that is prone to outbreaks when high levels of nitrogen (N) fertilizer are applied to rice. The larvae feed by scraping the mesophyll cells of leaves, which are mainly composed of chloroplasts containing significant levels of elemental magnesium (Mg). To determine the cause of N fertilizer-induced rice leaffolder outbreaks and the effects of Mg and Mg uptake on the rice leaffolder, the changes in the life history traits and biochemistry of C. medinalis larvae feeding on rice leaves treated with different Mg and N concentrations were investigated in this study. The results showed that foliar treatment using different Mg concentrations under hydroponic culture conditions significantly decreased the developmental duration (days) (DD) of the larvae and pupae but did not influence the pupation rate or adult emergence rate. The number of eggs laid by adult females and the protein content and total sugar content in the larvae and pupae significantly increased with increasing Mg concentrations. Under soil culture conditions, the DD for the larvae and number of eggs laid by adult females significantly increased with increasing nitrogen fertilizer levels, but the applied fertilizer did not influence the DD in the pupae, pupation rate, or adult emergence rate. In contrast, the DD for adults decreased with increased fertilizer levels. In hydroponic culture, Mg in the culture solution and Mg foliar sprays significantly increased the Mg content in rice leaves. In soil cultures, the use of N fertilizer and Mg foliar spray did not significantly increase the leaf Mg content, except at a concentration of 12.5 g/L, indicating that the leaf Mg content may be related to the root uptake of Mg.
水稻叶蝉，褐飞虱（鳞翅目：螟蛾科），是一种水稻害虫，当大量施用氮肥时，它很容易爆发。幼虫通过刮取叶片的叶肉细胞来取食，而这些细胞主要由含有大量元素镁（Mg）的叶绿体组成。为了确定氮肥诱导水稻叶蝉爆发的原因以及 Mg 和 Mg 吸收对水稻叶蝉的影响，本研究调查了不同 Mg 和 N 浓度处理的水稻叶片对 C. medinalis 幼虫生活史特征和生物化学的影响。结果表明，水培条件下不同 Mg 浓度的叶面处理显著缩短了幼虫和蛹的发育时间（天数）（DD），但不影响蛹化率或成虫羽化率。成虫雌虫产卵数以及幼虫和蛹的蛋白质含量和总糖含量随着 Mg 浓度的增加而显著增加。在土壤培养条件下，幼虫的 DD 和成虫雌虫产卵数随着氮肥水平的增加而显著增加，但施用的肥料并不影响蛹的 DD、蛹化率或成虫羽化率。相比之下，成虫的 DD 随肥料水平的增加而降低。在水培培养中，培养溶液和叶面喷施的 Mg 显著增加了水稻叶片的 Mg 含量。在土壤培养中，使用 N 肥料和叶面喷施 Mg 并没有显著增加叶片的 Mg 含量，除了在 12.5 g/L 的浓度下，这表明叶片的 Mg 含量可能与根对 Mg 的吸收有关。
