Physiological responses to Nilaparvata lugens in susceptible and resistant rice varieties: allocation of assimilates between shoots and roots.

Nilaparvata lugens (Stål) is a typical vascular feeder, primarily sucking the phloem sap of host plants. Its feeding on rice, Oryza sativa L., plants changes the pattern of allocation of assimilates between roots and shoots, and the root:shoot (R/S) ratio of assimilates is often measured as an index of physiological responses to N.

Reproduction-flight relationship in the beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae).

To evaluate the relationship between reproduction and migratory flight, we examined ovaries, tethered flight, and egg laying in the beet armyworm, Spodoptera exigua (Hübner). Ovarian development in female S. exigua was classified into five stages in relation to the postemergence age of the moths.

Changes of zeatin riboside content in rice plants due to infestation by Nilaparvata lugens (Homoptera: Delphacidae).

The effect of Nilaparvata lugens (Stål) (Homoptera: Delphacidae), infestation on the content of zeatin ribosides (ZR) in rice plants was investigated with enzyme-linked immunosorbent assay. Hydroponics experiments were conducted on 'Zhendao 2' rice, in which plants were subjected to N. lugens infestation at three nonhopperburn-causing densities (15, 30, and 60 nymphs per hill) for 2, 4, 6, and 8 d and at one hopperburn-causing density (240 nymphs per hill) for 2, 4, and 6 d, respectively.