Mechanism of resistance of peanut, Arachis hypogaea L. against the peanut leafhopper, Empoasca ricei Dworakowska and Pawar

Five peanut entries, namely NC Ac 343 (resistant), Myria (PC) (resistant), UPL Pn 4 (intermediate), UPL Pn 6 (susceptible) and IPB Pn 83-68-140 (susceptible), were tested in the greenhouse and screencage to determine the mechanism of resistance to the leafhopper. The test insect was identified as Empoasca ricei Dworakoruska and Powar. It was found that the leafhopper were most attracted to the 55 to 75-day-old plants. IPB Pn 83-68-140 was the most preferred variety for feeding and oviposition. It attracted the most number of adults that settled on the plants, had the highest number of eggs oviposited and had the greatest amount of honeydew excreted and protein ingested. NC Ac 343 was the most resistant variety with the lowest number of adults that settled on the test plants in a free-choice test. It was alos observed to have 34.4 trichomes per microscopic field, which is twice higher than that of IPB Pn 83-68-140 and UPL Pn 6 and has hard leaf petiole based on piercing pressure test. Antibiotic effect was demonstrated on the resistant NC Ac 343. Adult life span was affected most and the insects survived only for 3.67 days compared to 9.89 days on the susceptible variety. IPB Pn 83-68-140 had the highest moisture content but had the lowest protein content. NC Ac 343 had the highest percent tannins and lowest moisture content and percent crude fiber. These characters, except for percent tannins and phenols, seemed to have significantly contributed to the resistance of NC Ac 343 to peanut leafhopper. Myria (PC) demonstrated some level of tolerance to the peanut leafhopper. The negative correlation implies that the harder the leaf petiole and midrib or the higher the trichome density, the more resistant are the plants to the leafhoppers. In addition, a greater leaf area would make the plant more susceptible. The life cycle of E. ricei was studied.