Wheat Curl Mite and Wheat Streak Mosaic in Moderate Trichome Density Wheat Cultivars
- T. L. Harvey ,
- T. J. Martin and
- D. L. Seifers
The landing efficiency of the wheat curl mite (WCM), Eriophyes tulipae, is increased on wheat (Triticum aestiwm L.) cultivars that have high densities of leaf trichomes. This results in a higher incidence of wheat streak mosaic (WSM), which is caused by wheat streak mosaic virus (WSMV) and vectored by the WCM. This study was conducted to determine if moderate levels of leaf trichomes, found on many commonly grown cultivars, can have a significant effect on a cultivar's susceptibility to WSMV. Cultivar trichome density was assessed on greenhouse-grown plants. The relative ability of WCM to land on the cultivars was tested in the greenhouse by exposing the plants to airborne WCM and making WCM counts before reproduction occurred. The incidence of WSM in the field was assessed by the presence or absence of visual symptoms and numbers of WCM in spikes were measured during the 1987 and 1988 crop years, at Hays, KS. ‘Arkan’ and ‘TAM 108’ had moderate trichome densities on leaves two, four, and six (three-leaf mean 28.4 and 22.8 mm−2, respectively) and were more heavily infested by WCM in greenhouse and field tests when compared to cultivurs (Century, TAM 107, Lurned, and Newton) that have low trichome densities (6.0, 8.6, 5.0 and 5.7 trichomes mm−2, respectively). The cultivurs with moderate levels of leaf trichomes also had more plants with WSM in both years. Cultivars (Century and TAM 107) with the rye (Secale cereale L)-derived WCM resistance and few trichomes had the lowest incidence of WSM. Some cultivars now widely grown in Kansas may have sufficient pubescence to significantly increase their susceptibility to WSMV. New cultivars developed for areas where WSMV is a production constraint would probably benefit from having leaves with low trichome density.
Copyright © 1990.