Manejo da fusariose na pimenta-do- reino cv. Bragantina

Abstract

The Black pepper (Piper nigrum L.) is a spice of great economic value, consumed worldwide. In Brazil, its production has been limited by the fusariosis, the main disease of the crop, caused by the fungus Fusarium solani f. sp. piperis, causing the reduction of the plantations in the Field and until the plant death. Considering the difficulties and limitations in controlling this disease, the search for new alternative control methods has become quite promising in the country's producing areas. Thus, the objective of this work was to evaluate the effect of essential oils, plant extracts and organic matter in the control of fusariosis in black pepper. Two in vitro experiments were carried out at the Phytopathology Laboratory of the Agricultural Sciences Center of the Federal University of Alagoas (CECA / UFAL): the first evaluated the effect of essential oils of neem, spearmint, copaiba, eucalyptus, coconut and garlic in different (6 x 4) + 2. The second one, which evaluated the effect of the crude aqueous extracts (EBA) at the concentrations of 5, 10, 10, 15, 25 and 50 μL.mL -1 , 15 and 20%, with a completely randomized experiment in a factorial scheme (5 x 4) + 2, both with six replicates, on the inhibition of mycelial growth of the pathogen in BDA medium. From the best "in vitro" results, na experiment was carried out with Pepper worm seedlings inoculated with F. solani mycelium discs, which were sprayed with 20 mL of the essential oils of mint and neem at doses of 50 and 75 μL.mL -1 and with the crude aqueous extracts of caetano- melon and cassava in concentrations of 10 and 15%. The fungicide was brushed in the stems of the pulp-shaped plants at a dose of 0.2 g. 100 mL -1 . The design was completely randomized, with ten treatments and five replicates. In another experiment, organic residues of coconut husk, cassava husk, eucalyptus leaves, neem and black pepper were evaluated at a dose of 25, 50, 75 and 100 g.Kg -1 were incorporated into the soil for the control of fusariosis in pepper plants, being evaluated at 30, 60 and 90 days after inoculation of the pathogen with a suspension of 1.8 x 10-6 con/mL. The data were submitted to analysis of variance and regression and the means were compared by the Tukey test at the 5% probability level. Essential oils of peppermint and neem (50 and 75 μL.mL -1 ) and extracts of melon-de- cassetane and cassava (10 and 15%) provided the highest percentages of mycelial inhibition (91.61, 100, 41.74, 45.96, 61.01, 57.61, 51.53 and 55.48%), respectively. The EBA of caetano melon (15%) and the essential oil of mint (75 μL.mL -1 ), promoted the lowest disease rate, with 24 and 28% respectively. Organic residues of cassava husk and neem leaves were the most efficient in the control of fusariosis at 30, 60 and 90 days.