THE PEANUT SHELL MYCOBIOTA OF DETACHED VS MECHANICALLY HARVESTED PODS EITHER TREATED OR NOT TREATED WITH FLUTOLANIL

Flutolanil (Moncut) was applied to peanut (Arachis hypogaea) cv. Florunner at a single rate of 2.24 kg a.i./ha at four locations. Peanut pods from treated and control plots were harvested mechanically by combine, and mycoflora from these shells were compared with mycoflora from shells of detached pods removed from the soil 28-35 days after harvesting. Shells were plated in the laboratory, and over 85% of the 6,648 cultures of fungi obtained were Deuteromycetes. The nine most common genera, with >100 isolations, were Alternaria, Curvularia, Fusarium, Lasiodiplodia, Mucor, Nigrospora, Phoma, Rhizoctonia, and Trichoderma. Fusarium spp. were isolated most frequently and comprised 42% of the total cultures. Flutolanil treatment significantly decreased the incidences of Rhizoctonia solani AG-4 and Trichoderma spp. Incidences of other potential pathogens, such as Fusarium solani and F. oxysporum, were higher in the flutolanil-treated plots than in the control plots. Colonization by Rhizoctonia AG and CAG, Fusarium, Mucor, and Trichoderma spp. was significantly greater in shells from detached pods. Isolation frequencies of Alternaria, Curvularia, Nigrospora, and Phoma spp., however, were lower from shells of detached pods than from shells of mechanically harvested pods. Isolation frequencies of the mycotoxin-producing fungi Aspergillus spp. were low for both mechanically harvested and combined shells.