Influence of Maize mosaic virus and host plant genotypes on the bio-ecology of Peregrinus maidis

Abstract

Maize mosaic virus (MMV; Rhabdoviridae) is a plant nucleorhabdovirus transmitted in a persistent-propagative manner by the corn planthopper, Peregrinus maidis. The fitness of P. maidis developing on healthy or MMV-infected corn leaves from either young (less than 30 days old) or old (more than 58 days old) corn plants were examined. Since MMV is acquired at a low rate, the planthoppers that developed from the infected leaves were segregated into 2 categories as determined by ELISA tests; MMV-infected, and MMV-exposed. Planthoppers that developed on healthy leaves were deemed "unexposed" and used as a control. Mean developmental time of MMV-infected and unexposed planthoppers were not significant different; however, MMV-exposed planthoppers developed slightly, yet significantly slower than the previous two categories. Development on younger leaves was significantly faster compared to that on older leaves. Longevity was not significantly different. However, unexposed planthoppers were more fecund then both MMV-exposed and MMV-infected planthoppers, which displayed a similar reduced fecundity. Since the abundance of wing forms may vary in response to host-plant physiology, the influence of MMV on the production of macropters and brachypters was examined. The proportion macropters produced on young healthy and MMV-infected leaves were similar, but a significantly higher proportion macropters were produced on older MMV-infected leaves compared to healthy leaves of similar age. Our findings suggest MMV may indirectly influence the dispersal of the corn planthopper through host-plant infection.