Quantifying Risk for the Northern Root-knot Nematode, Meloidogyne Hapla, in Potato in New York State PDF Download

Author: Adrienne Marie Gorny
Publisher:
ISBN:
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Languages : en
Pages : 207

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Book Description
The Northern root-knot nematode, Meloidogyne hapla, is an important soilborne pathogen of potato in New York State. Initial pathogen populations (Pi) are often inversely correlated with crop loss and damage, with the economic threshold representing the Pi likely to result in significant crop loss, thus justifying use of control tactics. However, the economic threshold for M. hapla in potato in New York State is not well understood. Furthermore, standard methods of enumerating populations of nematodes from soil are time consuming and error prone. This research sought to quantify the risk of crop loss associated with M. hapla Pi, and develop a DNA-based soil test for prediction of risk. A method for isolating nematode DNA from 100 g of soil using super paramagnetic iron oxide nanoparticles was developed and tested using artificially inoculated soil and field collected samples. A species-specific, real-time quantitative PCR (qPCR) assay targeting the root-knot nematode effector gene 16D10 was developed for quantifying M. hapla. Spatial and spatiotemporal analysis of M. hapla and root-lesion nematodes, Pratylenchus spp., was conducted by intensively sampling three commercial potato fields in New York State. This informed enhanced sampling strategies and evaluated the potential for site-specific nematicide application. The influence of M. hapla Pi on crop loss was assessed by quantifying M. hapla Pi in commercial potato fields through manual extraction and a nested qPCR assay, and investigating associations with yield components. M. hapla Pi did not have a significant effect on total yield, number of tubers, tuber diameter, or tuber galling severity, suggesting the economic threshold for M. hapla in potato is higher than previously regarded (approximately 100 M. hapla second-stage juveniles (J2s) per 100 g soil), and/or tolerant cultivars were used. The response of the commercial potato cvs. Eva and Lamoka to differing Pi of M. hapla and P. penetrans was assessed through replicated field trials. Yield was not impacted even at the highest Pi tested (500 M. hapla J2s or 1,000 P. penetrans nematodes). These results will be used to guide future research to refine economic thresholds, explore advanced nematode management options, and assess potato cultivar susceptibility to plant-parasitic nematodes.