Resistance and tolerance of grapevine rootstocks to citrus nematode (Tylenchulus semipenetrans)

Abstract

Seven grapevine (Vitis spp.) rootstocks, and 4 commercial cultivars were screened in pots for resistance and tolerance to the citrus nematode Tylenchulus semipenetrans. Ramsey was highly resistant, Dog Ridge, Schwarzmann, Freedom, 16 16, K5 1-40 and K5 1-32 were resistant, but K5 1-32 was not tolerant of the nematode. All 4 commercial Vitis vinfera cultivars, Cabernet Sauvignon, Doradillo, Muscat Gordo Blanco and Sultana were susceptible. Resistance ratings were based on the number of females and the number of larvae per gram of root. A staining and maceration technique was compared with a simple incubation technique for effectiveness of female detection on roots. When the number of females per g of root was low, the incubation technique detected females in more samples and the results were less variable than with the staining technique.