Effects of the major nutritional substances and micro-structure of rice plants on the host preference of the small brown planthopper, Laodelphax striatellus
Abstract:The host preference and its factors of the small brown planthopper, Laodelphax striatellus (Homoptera: Delphacidae) on rice cultivars were studied in both aspects of plant nutrients and micro-structure of plant tissues. The planthoppers settled on rice plants and the water content, soluble sugars, protein content and crude fiber in 12 rice cultivars were measured. The micro-structure of rice leaves and stems and the distribution of silicon cells were observed using laser scanning microscopy. The results showed that crude fiber was the decisive factor that affected the preference of L.striatellus to its host. The insect density was significantly and negatively correlated with crude fiber (r=-0.96), and significantly and positively with protein content (r=0.79) and water content (r=0.89). Plant soluble sugar had no significant effect on the preference of L.striatellus. When observing the micro-structure of plant tissues, it was found that the cultivars with high density and volume of silicon cells, wider leaf venation and narrower venation intervals showed higher resistance against L.striatellus.