FERTILIZANTES ORGÂNICOS E MINERAIS NO MANEJO DE Meloidogyne javanica EM QUIABO (Abelmoschus esculentus)

Abstract

Okra is a highly prized vegetable in Brazilian cuisine and widely produced in the country. One of the main phytosanitary problems facing this crop is nematodes from the genus Meloidogyne, which, in high populations, can significantly reduce productivity. The incorporation of mineral and organic fertilizers can promote plant health by enabling the crop to develop defenses against phytonematode attacks. Therefore, this study aimed to evaluate the effect of different mineral and organic fertilizers on controlling Meloidogyne javanica in okra crops. A completely randomized design was used, consisting of 12 treatments and six replicates, totaling 72 experimental units, being the treatments: T1: Diatomaceous earth (20 g L-1), T2: Diatomaceous earth (30 g L-1), T3: Calcium (10 g L-1), T4: Calcium (20 g L-1), T5: Calcium silicate (20 g L-1), T6: Calcium silicate (30 g L-1), T7: Rock dust (2 g L-1), T8: Rock dust (4 g L-1), T9: Chitin (1.5 g L-1), T10: Chitin (3 g L-1), T11: control 1 (inoculated), T12: control 2 (without inoculation). Then, each okra plant was inoculated with 5,000 M. javanica eggs. Chlorophyll content was evaluated 15 and 45 days after inoculation, and 60 days after inoculation, the following characteristics were evaluated: plant height, number of eggs, number of galls, reproduction factor, and fresh root and shoot mass. Data were subjected to analysis of variance and the Scott-Knott mean test (P≤0.05). The treatment with 30 g L-1 diatomaceous earth showed better vegetative development, greater plant height, and greater biomass, followed by calcium and calcium silicate. Furthermore, 30 g L-1 diatomaceous earth controlled 85.53% of M. javanica eggs during the investigation. It was concluded that, under experimental conditions, although the nematode M. javanica affected the development of okra, treatment with diatomaceous earth at a dose of 30 g L⁻¹ resulted in better vegetative development and lower reproduction of the nematode, being it recommended for M. Javanica control. KEYWORDS: Root-knot nematodes, alternative control, organic residues, diatomaceous earth, chitin, silicate.