Microorganisms as growth promoters of Acmella oleracea grown under different cultivation systems

A great challenge to overcome is how to maintain and increase the productivity of vegetables, such as jambu (Acmella oleracea), by using natural processes and living organisms that stimulate plant production and release fewer toxic residues into the environment. The objective of this study was to evaluate the growth of A. oleracea, based on biometric, and physiological responses, following the application of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae and the growth promoter Trichoderma asperellum, under protected and unprotected planting systems, in the rainy and dry seasons of the Amazon. Two trials were conducted simultaneously, in randomized blocks, in a commercial area of peri-urban agriculture in the municipality of Ananindeua, Par & aacute; state, Brazil, in protected and unprotected hanging beds. Metarhizium anisopliae, B. bassiana, and T. asperellum isolates promoted growth in jambu in protected and unprotected plantation systems, in both crop cycles. Of note, M. anisopliae matched the results obtained with the growth promoter T. asperellum and stood out for favoring greater performance in all of the evaluated growth variables, especially in the protected cultivation system and in rainy season. In addition, A. oleracea grew better in all treatments in a protected planting system and in both evaluated periods. Therefore, A. oleracea treated with M. anisopliae, B. bassiana, or T. asperellum presented better growth, produced more biomass, and exhibited superior gas exchange.