Endophytic fungi as growth promoters in banana plantations

Abstract

Endophytic fungi produce bioactive metabolites that activate the defenses of host plants. They are a cleaner alter- native to the use of nematicides, however, there is limited information on their actions as promoters of growth in field conditions. The effect of four endophytic fungi on the growth of banana plants was evaluated. Six treatments were formulated: two strains of Trichoderma atroviride from Guatemala (T1) and Costa Rica (T2) and; two strains of Fusarium oxysporum from Talamanca (T3) and Sixaola in Costa Rica (T4), a chemical control (T5) with the use of nematicides and an absolute control (T6). The trial was established in a completely randomized design with five measurements over time. The plants used in the planting were of the clone “Valery y Williams”. The variables plant height, pseudostem circumference and leaf emission were evaluated every 15 days under field conditions and, in the root system, functional and dead weight, length and volume, index of severity caused by phytonematodes and necrotic percentage in laboratory conditions. The plants protected with the endophytic fungi had a significantly higher growth than those of the chemical control, reflected in higher height (13.62 %), pseudostem circumference (10.75 %), leaf emission (4.87 %), length (8.12 %) and volume (9.37 %) of roots. In the health of the radical system was expressed in greater functional weight (8.12 %), lower deadweight (-13.0 %), higher severity index (19.5 %) and lower necrotic percentage (-5 %). The T1 and T4 promoted the best responses in the plants.