Summary
Meloidogyne hapla and Pratylenchus penetrans are important plant-parasitic nematodes affecting potato in New York and the Northeastern United States, yet little is known of their spatial patterns and spatiotemporal dynamics. Spatial patterns of M. hapla and Pratylenchus spp. were quantified using semivariogram analysis and Spatial Analysis by Distance IndicEs (SADIE). Nematode populations were assessed within each of three commercial potato fields in 2016 and 2017, with fields sampled on two occasions in-season. Semivariogram analysis and ordinary kriging indicated initial population densities to be spatially dependent over an average range of 110 m for M. hapla and 147 m for Pratylenchus spp. SADIE indicated Pratylenchus spp. to be significantly aggregated in nearly all fields (10 of 12 samplings, to 2.113). Meloidogyne hapla populations were aggregated in only three of 12 samplings ( to 1.738). Spatiotemporal analysis using the association function of SADIE indicated a strong and significant association between initial and final population densities of M. hapla and Pratylenchus spp. within fields. This information is fundamental for the development of enhanced sampling protocols for estimation of plant-parasitic nematodes and evaluating the feasibility of site-specific nematicide application in New York potato fields.
