RESISTANCE TO WHEAT CURL MITE (ACARI, ERIOPHYIDAE) IN GREENBUG-RESISTANT GAUCHO TRITICALE AND GAUCHO X WHEAT CROSSES

Greenbug-resistant 'Insave F.A.' rye, 'Gaucho' triticale, and crosses of Gaucho x wheat, Sel. 74G80-2 and Sel. 74G559-6, were compared with wheat cultivars for their reaction to the wheat curl mite, Eriophyes t ulipae Keifer, the vector of wheat streak mosaic virus. It was previou sly observed that rye generally is more resistant to the mite than whe at. In our study, Gaucho, which is the product of an Insave F.A. rye x 'Chinese Spring' wheat cross, and wheat lines derived from Gaucho x w heat crosses, showed a high degree of resistance to the mite, whereas the susceptible entries exhibited severe mite damage symptoms includin g leaf curling and trapping and large numbers of mites. The wheat stre ak mosaic virus was transmitted to all test entries by heavy initial i nfestations of viruliferous mites. Light infestations of 5 mites per p lant did not result in disease symptoms, except in mite-susceptible en tries. The results also indicate that the source of wheat curl mite re sistance in 'TAM 107' wheat, widely planted in wheat streak virus-pron e areas of the Great Plains, traces back to Gaucho triticale.