INFLUENCE OF TWO NACOBBUS ABERRANS ISOLATES FROM ARGENTINA ON THE GROWTH OF THREE TOMATO CULTIVARS

Abstract

Nacobbus aberrans attacks weeds and cultivated plants, causing drastic crop yield losses. The tomatoes ʻSupermanʼ and ʻMykonosʼ are marketed as nematode resistant, but with no specifications of the nematode species. Moreover, no studies have recorded the response of these cultivars to infection by N. aberrans. We analyzed the influence of two Argentine isolates of N. aberrans (Lules and Río Cuarto) on the growth of these cultivars and Platense, a known susceptible used as a positive control. Plant growth variables, number of galls and egg masses, and gall size were measured. Mykonos infected with the Lules isolate exhibited a decrease in stem diameter. In Superman, all infected plants showed reduced shoot dry weight. Platense did not show differences (P>0.05) in growth variables between treated and control plants, however, this cultivar showed the largest galls. The Lules isolate was more aggressive than the Rio Cuarto isolate and produced a greater number of galls and egg masses on Mykonos and Platense than on Superman. These findings indicate that Superman and Mykonos were efficient hosts of N. aberrans and cannot be considered resistant to either of the two nematode isolates.