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ARS Home » Pacific West Area » Maricopa, Arizona » U.S. Arid Land Agricultural Research Center » Pest Management and Biocontrol Research » Research » Publications at this Location » Publication #266612
Title: Impact of Lygus spp. (Hemiptera: Miridae) on damage, yield and quality of lesquerella (Physaria fendleri), a potential new oil-seed crop

Author
item Naranjo, Steven
item ELLSWORTH, PETER - University Of Arizona
item DIERIG, DAVID - US Department Of Agriculture (USDA)

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2011
Publication Date: 11/10/2011
Citation: Naranjo, S.E., Ellsworth, P.C., Dierig, D.A. 2011. Impact of Lygus spp. (Hemiptera: Miridae) on damage, yield and quality of lesquerella (Physaria fendleri), a potential new oil-seed crop. Journal of Economic Entomology. 104: 1575-1583.

Interpretive Summary: Lesquerella, a mustard native to the western U.S. is currently being developed as a commercial source of valuable hydroxy fatty acids that can be used in a number of industrial applications including bio-lubricants, biofuel additives, motor oils, resins, waxes, nylons, plastics, corrosion inhibitors, cosmetics and coatings. Castor is the only commercial source of these fatty acids which must be imported into the US. As a new crop, virtually nothing is known about the insects that inhabit the crop and what impact they might have on production. Lygus spp. plant bugs are common in lesquerella and are known pests of a number of crops where they feed flowers, and fruits. A four year replicated plot study was undertaken to evaluate the probable impact of these plant bugs on production of this new crop. Plant damage and subsequent seed yield and quality were examined relative to variable densities of Lygus spp. resulting from variable frequency and timing of insecticide applications. Increasing damage to various fruiting structures (flowers, buds, seed pods) was significantly associated with increasing pest abundance, particularly the abundance of nymphs, in all years. This damage, however, did not consistently translate into reductions in seed yield, individual seed weight or seed oil content. Negative effects on yield were not sensitive to the timing of pest damage (early vs. late season), but were more pronounced during years when potential yields were lower due to weed competition and other agronomic factors. Results suggest that if the crop is established and managed in a more optimal fashion, Lygus spp. may not significantly limit yield. Nonetheless, additional work will be needed once more uniform cultivars become available and yield effects can be more precisely measured.

Technical Abstract: Lesquerella, Physaria fendleri (A. Gray) S. Watson is a mustard native to the western U.S. and is currently being developed as a commercial source of valuable hydroxy fatty acids that can be used in a number of industrial applications including bio-lubricants, biofuel additives, motor oils, resins, waxes, nylons, plastics, corrosion inhibitors, cosmetics and coatings. The plant is cultivated as a winter-spring annual and in the desert southwest it harbors large populations of arthropods, several of which could be significant pests once production expands. Lygus spp. (Hemiptera: Miridae) are common in lesquerella and are known pests of a number of agronomic and horticultural crops where they feed primarily on reproductive tissues. A four year replicated plot study was undertaken to evaluate the probable impact of Lygus spp. on production of this potential new crop. Plant damage and subsequent seed yield and quality were examined relative to variable densities of Lygus spp. resulting from variable frequency and timing of insecticide applications. Increasing damage to various fruiting structures (flowers, buds, seed pods) was significantly associated with increasing pest abundance, particularly the abundance of nymphs, in all years. This damage, however, did not consistently translate into reductions in seed yield, individual seed weight or seed oil content, and pest abundance generally explained relatively little of the variation in crop yield and quality. Negative effects on yield were not sensitive to the timing of pest damage (early vs. late season), but were more pronounced during years when potential yields were lower due to weed competition and other agronomic factors. Results suggest that if the crop is established and managed in a more optimal fashion, Lygus spp. may not significantly limit yield. Nonetheless, additional work will be needed once more uniform cultivars become available and yield effects can be more precisely measured.