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Vulnerability of Pasture and Range Legumes to Fungus Gnats
Author(s) -
Springer T. L.
Publication year - 1995
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1995.0011183x003500020042x
Subject(s) - biology , vicia villosa , trifolium repens , agronomy , vigna , seedling , forage , botany , legume , cover crop
Fungus gnats, Bradysia spp., are best known as pests of greenhouse‐grown ornamentals, and some data suggests that fungus gnats may be pests of forage legumes; however, information is largely lacking about their effects on forage crops. This study was conducted to determine adult fungus gnat oviposition preference and seedling mortality for 15 legume species. Replicated free‐choice tests were conducted in the greenhouse in June 1992, and May and June 1994. Significant variation ( P ≤ 0.05) in oviposition preference was attributed to differences among legume species, experiments, and experiment by species interactions. Species accounted for 44% of the total variation, experiment by species interactions (14%), and experiments (9%). Though experiment by species interactions occurred, live species were commonly preferred. These were hairy vetch, Vicia villosa Roth; cowpea, Vigna unguiculata (L.) Walp subsp. unguiculata ; Illinois bundleflower, Desmanthus illinoensis (Michx.) MacM. ex Robinson & Fern.; woollypod vetch, Vicia villosa subsp. varia (Host) Corbiere; and yellow sweet‐clover, Melilotus officinalis Lam. Significant variation in seedling mortality was attributed only to legume species. All species tested were susceptible to feeding damage and seedling stand reductions of greater than 90% were caused by as few as one larva per seedling. Based on observations made in the greenhouse and the fact that fungus gnats have been reared from soil samples collected from field stands of white clover, Trifolium repeus L., fungus gnats may pose a threat during the seedling establishment phase of some forage legumes. Field studies with naturally occurring populations of fungus gnats are needed to determine the importance of these insects in reducing establishment and persistence of pasture and range legumes.