Effects of postinfection treatment of organophosphorus nematicide, fosthiazate, on fecundity and soil population of Meloidogyne incognita

Abstract

The organophosphorus nematicide, fosthiazate, was applied as an aqueous solution to the soil of potted tomato plants infected with Meloidogyne incognita to examine the effect of postinfection soil treatment on production of egg-masses and soil population densities of 2nd stage juveniles (J2). Fosthiazate was applied prior to egg-mass formation at 16 days postinoculation, or after egg-mass formation at 21, 26, 34, or 38 days postinoculation. The nematicide was applied at the concentration of 0.56, 1.67, or 5.0 ppm a. i. at 16 days postinculation or at 1.25, 2.5, or 5.0 ppm a. i. at 21, 26, 34, or 38 days postinoculation. All treatments were evaluated for production of egg-masses and soil J2 population densities at 47 days postinoculation. Number of egg-masses were reduced by 80-90% when the nematicide was applied at 5 ppm, 16, 21, or 26 days after inoculation of M. incognita. Applying 1.25 ppm fosthiazate 21 days after inoculation of M. incognita significantly suppressed egg-mass production. Numbers of J2 were also reduced by 70-90% at 5 ppm when the chemical was applied at 16, 21, or 26 days postinoculation, but the reduction in J2 numbers was less than 50% when 2. 5 ppm fosthiazate was applied.