Using cover crops to manipulate population densities of corn planthoppers and reduce its associated damage symptoms in corn - cover crop intercropping systems

Corn planthopper, Peregrinus maidis Ashmead (Hemiptera: Delphacidae) is a serious pest, which transmits Maize mosaic virus (MMV) causing dwarfing disease in corn. Feeding by high numbers of planthoppers can also cause symptoms of “hopper burn” to corn seedlings. The current approach to MMV management is solely depended upon resistant varieties, however, in many areas, high likelihood of natural mixed infestation of MMV with other virus limits the success of the current strategy. As an alternative, habitat manipulation experiments using cover crops were conducted to examine the effect on population densities of planthoppers and its associated damage to the corn plants as a tool for ecologically based pest management strategies. Three cover crops, buckwheat, Fagopyrum esculentum (Moench); cowpea, Vigna unguiculata and sunn hemp, Crotolaria juncea L. in corn intercropping systems were studied and compared with bare-ground habitat (corn monoculture). Results showed that population densities of planthoppers varied among the treatment habitats. Sunn hemp provided partial protection from planthopper infestation, resulting in significantly lower percentages hopper burnt and symptomatic MMV infected corn plants compared to all other treatments. In conclusion, tall sunn hemp plants might have provided a barrier to planthoppers, impeding their movement in the cornfield resulting less incidence of damaged plants.