SUSCETIBILIDADE DE PLANTAS DANINHAS FREQUENTES EM ÁREA DE CULTIVO DO CERRADO GOIANO A Meloidogyne javanica

Abstract

The Meloidogyne javanica nematode decreases the productive potential of cultivable plants, making it necessary to adopt management measures such as the control of host weeds and nematode multipliers in the field. The goal of this work was to evaluate the susceptibility of frequent weeds in a cultivated area of Cerrado Goiano to M. javanica. The experiment was carried out in the municipality of Pontalina, in the south of the State of Goiás, under ambient temperature conditions, with an average of 23 °C, in a completely randomized design. The treatments consisted of five species of plants: 1) control, tomato 'Santa Cruz', 2) Desmodium tortuosum, 3) Ageratum conyzoides, 4) Amaranthus retroflexus e 5) Emilia sonchifolia; inoculated with M. javanica, with seven replications, totaling 35 experimental units. The seeds were sown in polyethylene whiting and after completing two to three pairs of leaves, a plant was transplanted per pot with a capacity of 1L containing soil substrate and sand in a 3: 1 (v / v) ratio. At 10 days after transplantation, weeds were inoculated with 5,000 eggs and juveniles of second stage (J2) of M. javanica. At 65 days after inoculation, the variables number of galls (NG) and eggs (NO) induced by M. javanica were evaluated to calculate the gall index (IG), and reproduction factor (FR). It was found that, according to the NO variable, the Emilia sonchifolia behaved as resistant, presenting NO = 3,582; for the species Desmodium tortuosum it was classified as immune, NO = 0. On the other hand, the Ageratum conyzoides and the Amaranthus retroflexus showed susceptibility reactions with number of eggs = 6,720 and 28,512, respectively. Therefore, based on the results in the infested field these weeds can function as multipliers of the nematode. The results obtained highlight the importance of the management of weeds, especially the Ageratum conyzoides and Amaranthus conyzoides in areas already infested with M. javanica.