Velvetleaf: A plant with adverse impacts on insect natural enemies

We investigated the effect of velvetleaf, Abutilon threophrasti L., leaf ag e and glandular trichome exudate on Eretmocerus eremicus n. sp. Rose & Zoln erowich parasitism of silverleaf whiteflies, Bemisia argentifolii Bellows & Perring, in the greenhouse. The impact of glandular trichome exudate on en trapment of natural enemies in the field also was examined. Parasitism of w hiteflies in the greenhouse was minimal and 31% of the parasitoids released to attack whiteflies were found entrapped in exudate of glandular trichome s and died. In the field, velvetleaf is a source of mortality to natural en emies and significantly more natural enemies were entrapped in glandular tr ichomes of control plants than on plants that were wiped to remove glandula r exudate. Behavioral observations revealed that Eretmocerus in small arena s located fewer whitefly hosts on leaf disk of veletleaf compared with the number of hosts located an glabrous or pubescent melons, Cucurbita melo L. Parasitoids accessing velvetleaf spent much of their time off the leaf disk , grooming, presumably to remove the exudate that was encountered on the le af. As such, less overall time was spent searching velvetleaf for hosts com pared with time spent searching melons.