Location: Mycology and Nematology Genetic Diversity and Biology Laboratory
2020 Annual Report
Accomplishments
1. Alfalfa cyst nematode is identified as an emerging pest. Annual crop losses due to nematodes and diseases are estimated at 10% of the $9.3 billion alfalfa crop in the United States, with nematodes posing a significant emerging threat. ARS scientists from Beltsville, Maryland, and a university scientist from Idaho used anatomical and molecular features to identify juvenile and adult nematodes collected from alfalfa fields in Utah as the alfalfa cyst nematode. This finding represents the first record of alfalfa cyst nematode from this state and is further evidence of a possible new threat to alfalfa, which is grown in all 50 states and is the third most valuable field crop. This information will be used by plant pest management specialists and regulatory officials to manage and potentially contain this nematode to prevent inadvertent movement to additional areas.
2. Cactus cyst nematode was identified from Idaho. Cyst nematodes damage the roots of many kinds of plants throughout the world, including cactus plants, which serve as drought-tolerant forage for livestock and protect against soil erosion in rangeland systems. In this study, a team of ARS scientists and a colleague from Idaho analyzed anatomical and molecular traits to identify the cactus cyst nematode for the first time from a cactus in Idaho. This discovery is significant because new molecular information obtained for this species will facilitate future identifications and guide researchers and diagnosticians who need to distinguish among important cyst nematodes that occur in arid soils.
3. Goosegrass cyst nematode identified from corn in Indiana. Cyst nematodes cause significant economic and yield losses on $50 billion corn crop each year. In this study, ARS researchers from Beltsville, Maryland, along with university scientists in Indiana identified and characterized the goosegrass cyst nematode (Vittatidera zeaphila) from a corn field in Indiana using anatomical features and DNA markers. This work significantly expanded the molecular information useful for identifying this species and is important because it documents the second state in which this nematode was found. Scientists, extension agents and action agencies engaged in nematode research and control will use this research to track the distribution of this nematode on corn.
4. Guava root-knot nematode identified from cotton in Brazil. The guava root-knot nematode (Meloidogyne enterolobii) is an extremely virulent species of root-knot nematode, which has been steadily spreading into new crops and locations around the world and poses a significant threat to both vegetable and agronomic crops. A team of researchers including ARS scientists from Beltsville, Maryland, and Tifton, Georgia, with scientists from Brazil, used molecular diagnostics to identify this nematode for the first time from cotton in Brazil. This research also showed that the nematode could reproduce successfully on seven genotypes of cotton, several of which contained resistance to other root-knot nematodes. This nematode poses a major threat to the $6 billion cotton crop in the United States due to the total lack of known resistance to this nematode. This discovery will enhance the ability of first responders, and research scientists track the spread of this damaging pest and develop and deploy new management methods to areas where they are most needed.
Review Publications
Skantar, A.M., Handoo, Z.A., Kantor, M.R., Carta, L.K., Faghihi, J., Ferris, V. 2020. Characterization of Vittatidera zeaphila (Nematoda: Heteroderidae) from Indiana with molecular phylogenetic analysis of the genus. Journal of Nematology. 52:1-8. https:/doi:10.21307/jofnem-2020-024.
Skantar, A.M., Handoo, Z.A., Kantor, M.R., Hult, M.N., Hafez, S.A. 2019. First report of the cactus cyst nematode, Cactodera cacti, from a cactus garden in Idaho. Journal of Nematology. 51:1-6. https://doi.org/10.21307/jofnem-2019-044.
Handoo, Z.A., Skantar, A.M., Hafez, S.A., Kantor, M.R., Hult, M.N., Rogers, S.T. 2020. Molecular and morphological characterization of the alfalfa cyst nematode, Heterodera medicaginis, from Utah. Journal of Nematology. 19(52):1065-1081.
Galbieri, R., Davis, R.F., Scoz, L., Belot, J., Skantar, A.M. 2020. First report of Meloidogyne enterolobii on cotton in Brazil. Plant Disease. https://doi.org/10.1094/PDIS-02-20-0365-PDN.
