EFFECT OF ARBUSCULAR MYCORRHIZA ON COFFEE (Coffea arabica L.) PLANTS INFECTED BY THE NEMATODE OF COFFEE CORKY-ROOT DISEASE

Abstract

Arbuscular mycorrhizae may reduce the susceptibility and damages
caused by pathogens. Coffee is a crop that has a high degree of
mycotrophy and it has been proven that mycorrhizas improve plant
development. The purpose of this study was to compare the effect
of plants inoculated with consortia of mycorrhizal fungi and their
interaction with phytopathogenic nematodes. Seven consortia of
native coffee plantation mycorrhizae fungi were isolated, and the
interaction of the different inoculums was compared with the rootknot
nematode that causes coffee corky-root disease, also called
corchosis. For this purpose, coffee plants were inoculated with the
seven consortia of AMF and after seven months they were inoculated
with 1500 juveniles and eggs; the following were defined: dry weight,
root volume, leaf area and number of leaves, extraradical mycelium,
chlorophyll quantity, percentage of colonization, number of spores,
and population of nematodes. The root system volume of plants
inoculated with the pathogen decreased by up to 70.93%; however, the
plants observed were apparently healthy and vigorous in the aerial part,
which leads us to assume that although the nematode penetrates the
root and damages it, the fungal hyphae allow the passage of nutrients
and therefore the plant attains its development.