Potencial de extrato de cabacinha no controle de Meloidogyne enterolobii em pimentão.

Abstract

The bell pepper (capsicum annuum L.) is cultivated practically all over the world, giving prominence to tropical and temperate regions. In Brazil, bell pepper has great socioeconomic importance, being among the ten most consumed vegetables. In recent years, cultivation began to be carried out in a protected environment, due to the increase in productivity and quality of the fruits. However, successive crops in the same area, together with inadequate management techniques, have led to an increase in root diseases, especially meloidogynosis, by the species: Meloidogyne javanica and M. incognita. Recently, a new species, M. enterolobii (Syn. M. mayaguensis), has gained relevance, as effective sources of resistance against other nematodes have been shown to be ineffective in controlling them. The search for alternative methods of phytonematoid control, which also aim to preserve the environment, has motivated research with extracts of plant origin. Thus, the objective of this study was to evaluate the potential of cabacinha extract (Luffa operculate Cogn.) in the control of M. enterolobii in sweet pepper culture. The experiment was carried out in the greenhouse and Phytopathology Laboratory of the Federal University of Campina Grande, in Pombal, PB. The experiment had a completely randomized experimental design, in a factorial scheme (2x10) and the factors consisted of two stages of ripening of gourd: green and dry, in the preparation of the plant extracts, with ten concentrations (10, 20, 30, 40, 50, 60, 70, 80, 90 and 100%), plus a Water control (0) and a chemical treatment, with five replications. For this, the pepper seedlings kept in pots were inoculated with 5,000 eggs/juveniles of M. enterolobbi, after 72 h, the treatments corresponding to 50 mL of the extracts were applied, divided into three applications (25 mL +25 mL + 25 mL), with an interval of fifteen days between them. Sixty days after the application of the treatments, the vegetative development of the plants was evaluated, such as: plant height, stem diameter, fresh and dry shoot phytomass, fresh root phytomass and root volume. The following were also estimated: number of galls, total number of juveniles in the soil, total number of juveniles and eggs in the roots, number of eggs and juveniles per root gram and reproduction factor. Among the agronomic characteristics studied, shoot dry weight (PASP) was the only one that had a significant effect between the factors stage of maturation and concentrations of gourd extract. On the characteristics of parasitism, there was a positive effect on the following variables: number of galls (NG), number of juveniles in the soil (NS), number of eggs in the soil (OS), eggs in the root (OR) and reproduction factor (RF). However, the variables number of juveniles at root (NR) and nematodes per root gram (NRG) responded significantly in isolation to the concentrations of cabacinha extract. The alcoholic extract of gourd has a biocidal effect on M. enterolobii in the pepper crop without causing a decrease in its vegetative development. On the other hand, for the effect of parasitism, it has a positive effect on the concentrations of green and dry extract higher than 20%.