The application of arbuscular mycorrhizal fungi and mycorrhizae helper bacteria combined with compost to reduce the Pratylenchus coffeae population in an Arabica coffee plantation

Abstract

Arbuscular mycorrhizal fungi (AMF) and mycorrhiza helper bacteria (MHB) are potential biological agents that control Pratylenchus coffeae, a major endoparasitic nematode in coffee plantations. An experiment was conducted to determine the role of AMF and MHB inoculants combined with compost in reducing plant damage and the number of nematodes in the soil and roots, as well as increasing the AMF infection rate in juvenile (JP) and mature (MP) Arabica coffee plants. The field experiment with a randomized block design was conducted with both juvenile (JP) and mature plants, consisting of 8 combination treatments and one control with three replications. The JP and MP plants received 1.5-50 g and 25-100 g AMF inoculant/plant and compost at doses of 5 or 7.5 and 10 or 15 kg/plant, respectively, while the MHB liquid inoculant concentrations were 10 mL and 100 mL, respectively. The control plants were not treated with AMF, MHB, or compost. The AMF and MHB inoculants combined with compost reduced leaf and root damage, but increased the degree of AMF infection in the roots of JP and MP. The nematode populations in roots and shoots of treated JP were reduced by 48.7-74.5% and 56.0 80.5%, respectively; in mature plants, the reductions ranged from 40.5 to 74.4% in roots and 44.0 to 75.4% in the soil. These results suggest that AMF, MHB, and compost effectively reduced P. coffeae infection in Arabica coffee plants under field conditions.