Use of native plant growth promoting bacteria (PGPR) in the control of Mycosphaerella fijiensis in organic banana plantations in Dominican Republic

Abstract

The production of organic bananas (Musa AAA L.) is one of the main export products of the Dominican Republic to the U.S. and European market. Approximately 50% of the leaf area of this crop is affected by the disease black Sigatoka, the causative agent Mycosphaerella fijiensis Morolet. The control of this disease with agrochemicals is common, which restricts its organic character and the feasibility of commercialization, which results in difficulties for its control. The objective was to use autochthonous plant growth promoting bacteria (PGPR) in the control of Mycosphaerella fijiensis in organic banana plantations. A randomized whole-block experimental design was used with four treatments and four replications. The treatments were three bacteria (MAM21, DARA33 and MOSY21) and one control; and 10 plants/treatments were evaluated. The plants were inoculated in the nursery with a bacterial broth at a rate of 20 ml each, at a concentration of approximately 6x10⁸ CFU ml^-1, one week before planting. The variables that indicate the evolution of the disease were measured by corrective black Sigatoka disease (CE), gross sum (SB), evolutionary sum (SEV), and evolutionary status (EE). Development: plant height (AL), pseudostem thickness (PS), number of leaves (NH) and banana productivity: bunch weight, finger grade. Statistical analyses were performed ANOVA, Duncan's Test and Principal Component Analysis (PCA). The results show the MOSY21 treatment (P. plecoglossicide) with the evolutionary status of the black Sigatoka disease at zero in different weeks, as well as better plant development and productivity. These bacteria can be used in the promotion of organic agriculture as they help improve plant development and productivity.