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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #154030
Title: RELATIONSHIP BETWEEN MELOIDOGYNE ARENARIA AND AFLATOXIN CONTAMINATION IN PEANUT

Author
item Timper, Patricia - Patty
item WILSON, D - UNIV. OF GEORGIA
item Holbrook, Carl - Corley
item MAW, B - UNIV. OF GEORGIA

Submitted to: Journal of Nematology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2004
Publication Date: 6/15/2004
Citation: Timper, P., Wilson, D. M., Holbrook, C. C., Maw, B. W. 2004. Relationship between Meloidogyne arenaria and aflatoxin contamination in peanut. Journal of Nematology. 36(2):167-170.

Interpretive Summary: Damaged and developing seed kernels of peanut are susceptible to colonization by fungi that produce aflatoxins prior to harvest. Our objective was to determine whether infection of peanut roots and pods by the peanut root-knot nematode increases aflatoxin contamination of the kernels when plants are subjected to drought stress. The experiment was conducted in 2001 and again in 2002 in microplots under an automatic rain-out shelter. The treatment combinations were plots with both nematode and fungal inoculum, with only nematodes, with only the fungus, and without either nematode or fungal inoculum. In treatments where fungal inoculum was added, aflatoxin concentrations were high and not affected by nematode infection; whereas in treatments without added fungal inoculum, aflatoxin concentrations were greater in kernels from nematode-infected plants than in kernels from uninfected plants. There was also an increase in aflatoxin contamination of kernels with increasing pod galling. Colonization of kernels by aflatoxin-producing fungi increased with increasing pod galling in 2001 but not in 2002. It is likely that the mechanism by which the peanut root-knot nematode increases aflatoxin contamination is through greater colonization of the kernel by fungi; however, the contribution of root and pod galling to this increase is unknown.

Technical Abstract: Damaged and developing seed kernels of peanut (Arachis hypogaea) are susceptible to colonization by fungi in the Aspergillus flavus group which, under certain conditions, produce aflatoxins prior to harvest. Our objective was to determine whether infection of peanut roots and pods by Meloidogyne arenaria increases aflatoxin contamination of the kernels when peanut is subjected to drought stress. The experiment was a completely randomized 2x2 factorial with six replicates per treatment combination. The treatment factors were nematodes (plus and minus M. arenaria inoculum) and fungus (plus and minus A. flavus inoculum). The experiment was conducted in 2001 and again in 2002 in microplots under an automatic rain-out shelter. In treatments where A. flavus inoculum was added, aflatoxin concentrations were high and not affected by nematode infection; whereas in treatments without added fungal inoculum, aflatoxin concentrations were greater in kernels from nematode-infected plants than in kernels from uninfected plants. There was also an increase in aflatoxin contamination of kernels with increasing pod galling (R2 = 0.83 in 2001, R2 = 0.43 in 2002; P < 0.04). Colonization of kernels by A. flavus increased with increasing pod galling (R2 = 0.18; P = 0.04) in 2001 but not in 2002. It is likely that the mechanism by which M. arenaria increases aflatoxin contamination is through greater colonization of the kernel by fungi in the A. flavus group; however, the contribution of root and pod galling to this increase is unknown.