Characterization of Antixenosis and Antibiosis of Corn Genotypes to Dichelops melacanthus Dallas (Hemiptera: Pentatomidae)

Abstract

Stink bugs are considered limiting pests to important crops worldwide. In Brazil, the green-belly stink bug, Dichelops melacanthus Dallas (Hemiptera: Pentatomidae), has become a key pest to the young phase of corn crop, being a problem especially when it succeeds soybean in the field. Injuries caused by this species vary from holes on new leaves to plant death in severe attacks. The main control technique used to this pest are seed treatment and insecticide spraying. Although both methods show some efficiency, factors as outbreaks in the resistance to insecticides and the different susceptibility existent among stink bugs population, leads to the search of other control strategies. Thus, less harmful tools to the environment and humans are highly desirable. In this sense, resistant plants appear as a valuable alternative for insect management, being compatible with other IPM methods. This study evaluated the resistance of 16 corn genotypes to D. melacanthus in order to characterize antixenosis and/or antibiosis expression. Antixenosis was accessed through preference multi-choice test with 5th instar nymphs. For antibiosis assessment, 60 2nd instar nymphs were confined on seedlings of 13 selected genotypes. Seedlings of IAC 8046, IAC 8390 and SCS 156 Colorado corn genotypes were less infested by D. melacanthus at 24 h after bugs were released indicating antixenosis expression. Genotypes IAC 8390 and JM 2M60 negatively affected some biological parameters of the green belly stink bug, indicating the occurrence of antibiosis. These genotypes can be useful to breeding programs focusing on corn resistance to stink bugs species.