Location: Crop Protection and Management Research
2013 Annual Report
2. Develop integrated strategies and control options for managing nematodes in cotton and peanut. 2.a. Enhance the efficacy and consistency of biological control of nematodes. 2.b. Identify new cultural control options for managing nematodes in cotton and peanut. 2.c. Develop integrated approaches for managing nematodes.
We completed two greenhouse trials to determine whether the efficacy of Paecilomyces lilacinus (a fungal pathogen of nematodes marketed as NemOut) could be enhanced by planting a winter cover crop. We found that nematode suppression by the fungus averaged 36% in fallow soil and 63% in soil that had a rye cover crop. We attempted to set up a third trial in the greenhouse, but we had poor growth of the cover crop. We will repeat it again this winter.
The first year of a field study is underway to determine whether high residue rye can suppress populations of M. incognita prior to planting cotton. We have killed the rye that was planted last fall and planted cotton in the late spring.
Greenhouse testing of sorghum entries to evaluate their suitability as a host for Meloidogyne incognita, the cotton root-knot nematode, is substantially completed. Preliminary tests had found levels of nematode reproduction ranging from almost none to extremely high, and our recent tests have verified those results. These findings were the catalyst for a new, collaborative project to identify DNA markers for nematode resistance genes in sorghum. Research is ongoing to evaluate the effect of both highly resistant and highly susceptible genotypes on nematode reproduction and on damage caused to the crop in the field.
A study evaluating cytokinin, a plant hormone that increases root growth, for its ability to reduce the damage caused to cotton by M. incognita has largely been completed. Cytokinin was shown by others to increase root system size in non-irrigated cotton in arid climates thereby increasing yields by drought tolerance, but increased root size was not seen in irrigated cotton. Increasing the size the root system could also make the plants more tolerant of nematode parasitism. We found no effect on cotton yield of cytokinin application in non-irrigated cotton in Georgia, and we conclude that in most years natural rainfall in Georgia will be sufficient to minimize any benefit from cytokinin.
Timper, P., Bouton, J. 2012. Variable response of non-ergot-producing strains of Neotyphodium coenophialum in tall fescue to lesion nematodes. In: Young, C.A., Aiken, G., McCulley, R., Strickland, J.R., Schardl, C.L., editors. Epichloae, endophytes of cool season grasses: Implications, utilization and biology. 1st edition. Ardmore, OK: The Samuel Roberts Noble Foundation. p. 40-43.
Olson, D.M., Webster, T.M., Scully, B.T., Strickland, T.C., Davis, R.F., Knoll, J.E., Anderson, W.F. 2012. Use of winter legumes as banker plants for beneficial insect species in a sorghum and cotton rotation system. Journal of Entomological Science. 47:350-359.
Yang, J., Benecke, S., Jeske, D.R., Rocha, F., Smith-Becker, J., Timper, P., Becker, J.O., Borneman, J. 2012. Population dynamics of Dactylella oviparasitica and Heterodera schachtii: Toward a decision model for sugar beet planting. Journal of Nematology. 44:237-244.
Davis, R.F., Aryal, S.K., Perry, C.D., Sullivan, D.G., Timper, P., Ortiz, B.V., Stevenson, K.L., Vellidis, G., Hawkins, G. 2013. Utilizing management zones for Rotylenchulus reniformis in cotton: Effects on nematode levels, crop damage, and Pasteuria sp. Crop Protection Journal. 50:53-60.
Timper, P., Holbrook Jr, C.C., Wilson, D.M. 2013. Contribution of root-knot nematodes to aflatoxin contamination in peanut. Peanut Science. 40:31-39. DOI: http://dx.doi.org/10.3146/PS12-14.1.