SUITABILITY OF 7 GRASS WEEDS AS HESSIAN FLY (DIPTERA, CECIDOMYIIDAE) HOSTS

Seven spp. of wild grasses, all common weeds in harvested North Caroli na wheat fields, were caged with ovipositing adults of the Hessian fly , Mayetiola destructor (Say). Grass spp. tested were Brachiaria platyp hylla (Grisebach) Nash, Cynodon dactylon (L.) Persoon, Digitaria sangu inalis (L.) Scopoli, Panicum dichotomiflorum Michaux, Setaria faberi H errmann, Setaria glauca (L.) Beauvois, and Sorghum halepense (L.) Pers oon. Seedlings of wheat (Triticum aestivum L.) were placed in selected cages to demonstrate that conditions permitted Hessian fly reproducti on (oviposition and larval establishment). No Hessian fly reproduction could be demonstrated on any of the wild grasses. Further, an extensi ve review of published experiments indicated that M. destructor reprod uction on non-Triticeae grasses is negligible. Thus, Hessian fly popul ation dynamics probably do not need to be considered when managing non -Triticeae grass weeds in double-cropped soybean. Within-cage location significantly affected intensity of infestation of wheat seedlings. I mplications for design of host preference experiments are discussed.