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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Research Project #432421

Research Project: Optimizing Anaerobic Soil Disinfestation for Management of Prunus Replant Problems-UCR Component

Location: Crops Pathology and Genetics Research

Project Number: 2032-22000-016-20-A
Project Type: Cooperative Agreement

Start Date: Dec 5, 2016
End Date: Mar 1, 2019

Objective:
1) Complete phase 1 optimization trials testing anaerobic soil disinfestation (ASD) substrates in greenhouse pots with field soil. 2) Conduct phase 1 optimization trials for ASD substrates and soil moisture levels in small field plots/field microplots. 3) Establish two replant trials in commercial almond orchards to compare optimized ASD treatments with conventional soil fumigation. 4) Transfer improved ASD technology to stakeholders.

Approach:
Obj. 1 - Three greenhouse trials testing efficacy of ASD substrates for control of plant parasitic nematodes (PPN) will be completed. Two almond orchard replant soils and ASD carbon substrates will be assembled for the testing. PPN will be added to soil as needed to ensure that both soils have lesion and ring nematode populations. At least six ASD carbon substrates will be collected from each type of candidate substrates and various combinations of the substrates. The two soils will be subjected to 8 treatments, including a non-treated control, a steam pasteurized control, and six different ASD treatments based on different carbon substrates and combinations of them. ASD and control treatments will be monitored over the 3 wks for temperature, reduction potential (Eh), and the soil pH. After treatment, the soils will be transplanted with Nemaguard peach seedlings. Treatment effects will be evaluated 8 wks after transplanting. Efficacy of ASD treatments will be assessed according to reduction potentials maintained and reductions PPN populations. Obj. 2 -. Two small-plot field trials testing efficacy of ASD substrates for control of PPN will be completed. Each replicate small field plot will be situated at a site previously devoted to almond trees and containing PPN. The micro field plots will be filled with soil that expresses Prunus replant disease (PRD) and contains PPN. Three carbon substrates / carbon substrate mixtures will be tested from those performing optimally in greenhouse trials. All ASD plots will remain covered with TIF plastic tarp for approximately 4 wks, when tarps will be removed and soil will be aerated. After dissipation of fumigant, soil will be sampled from all plots for nematode counts and will transplanted with Nemaguard peach seedlings. Obj. 3 – Arrangements will be made for conducting two almond orchard replant trials with a commercial grower in the San Joaquin Valley. The site of the trial will be affected by plant parasitic nematodes (based on sampling) and express PRD (based on bioassay). Substrate treatments will a nontreated control, a Telone C35 control, and at least three ASD treatments based on substrates that afforded optimal performance in greenhouse and microplot trials. Obj. 4 - Present oral talks and slide presentations summarizing effects of ASD treatments on control of PPN at UC Cooperative Extension meetings in Central Valley counties where almonds and stone fruits are grown. Execution of field days that include demonstrations of ASD treatments and their efficacy for control of PPN. Assist ARS PI and other UC scientists in preparation of guidelines for use of ASD to manage PPN populations (digital and printed formats). Present findings on efficacy of ASD for control of PPN at professional conferences (e.g., Ann. Intl. Res. Conf. on Methyl Bromide Alternatives; American Phytopathological Society, Society of Nematology) and in peer reviewed publications.