INOCULATION TIME AND INOCULUM DENSITY ARE DETERMINING FACTORS IN INDUCTION OF BREAKING OF RESISTANCE TO PHYTOPHTHORA CAPSICI IN CHILI PEPPER (CAPSICUM ANNUUM) BY NACOBBUS ABERRANS

摘要

Investigations were undertaken to determine the minimum inoculum density of Nacobbus aberrans required for breaking resistance to Phytophthora capsici in chili pepper (Capsicum annuum) cv CM-334, and the minimum time needed after nematode inoculation for CM-334 plants to become susceptible to P. capsici. In one experiment, the death of the plants inoculated with 3 × 10[sup5] zoospores of P. capsici occurred when inoculated with 2000 and 3000 J[sub2] of N. aberrans 21 days post inoculation with the nematode (57 and 71% mortality, respectively). In another experiment, CM-334 plants inoculated with 2000 J[sub2] of the nematode died when inoculated with 3 and 6 × 10[sup5] zoospores of P. capsici per plant (50 and 70% mortality, respectively). CM-334 plants inoculated with 2000 J[sub2] of the nematode and 3 × 10[sup5] zoospores of the fungus became susceptible to P. capsici (40% mortality) when the fungus was inoculated 21 and 28 days post-nematode inoculation.