Interference of aldicarb in infective forms of Meloidogyne incognita and its effects on reproduction in soybean

Abstract

The effect of aldicarb on mortality, motility, and reproduction of M. incognita in soybean was studied. The mortality of second-stage juveniles (J2) in aldicarb solution (5 and 50 μg mL-1) was only high at 20 days of exposure, being higher in the concentration of 50 μg mL-1 and lower in control (water). Motility was inversely proportional to the exposure time, and at 20 days of incubation, the number of J2 mobiles was statistically equal for both concentrations evaluated. There was a reduction inversely proportional to the number of galls and eggs per gram of root according to the J2 incubation time in water and aldicarb (5, 10, and 20 days). J2, when incubated in 50 μg mL-1 aldicarb for 5 and 10 days, always provided the same values regarding the number of galls and eggs per gram of root. The incubation for 20 days resulted in the loss of J2 infectivity, both in water and in aldicarb (5 and 50 μg mL-1), with practically no galls and eggs. When the J2 were incubated in the soil with the application of aldicarb solution (5 and 50 μg mL-1) or water (control), followed by soybean planting, 5, 10 and 20 days after, the J2 infectivity was null in the treatments with aldicarb (5 and 50 μg mL-1). However, when the J2-infested soil was sprayed with pure water (control), gall formation and reproduction decreased with the J2 incubation period, with a drastic reduction from the 5th day. Therefore, exposure to aldicarb affects the life cycle of M. incognita in soybeans.