Viabilidade e sobrevivência do inóculo de Heterodera glycines ra？a 3 no solo

alternative hosts of phytonematodes can cause nutritional restriction and affect infectivity and fertility of the nematode. in this study, we evaluated the effect of the host plant on inoculum viability of heterodera glycines race 3 and survival of this inoculum in soil. the nematode was multiplied in resistant (line l2300) and susceptible (cv. ouro) beans and susceptible soybeans (cv. ft-cristalina), and the egg suspensions were prepared from females collected on these hosts. to evaluate penetration of second stage juveniles and development of the nematode to the adult phase, suspensions of 2,000 eggs were placed in soybean 'ft- cristalina' plants (test plant). at ten days after inoculation, we evaluated the number of juveniles that penetrated the roots. the number of females per root system was evaluated at 30 days. the inoculum obtained from line l2300 resulted in fewer juveniles and females inside the roots of the test plant. the inoculum obtained from soybean resulted in higher penetration and development of the nematode. to evaluate the survival of the inoculum, cysts of h. glycines produced in the different hosts remained in the soil, without plants, for 18 months. the lower percentage of eggs that survived in the soil was originated from cysts multiplied in beans, line l2300 or cv. ouro. it can be concluded that the inoculum of h. glycines produced in bean plants, resistant or susceptible, has lower viability and survival in the soil.