EFFECT OF POST-PLANT APPLICATION OF VYDATE L ON CARROT INFECTED WITH SOUTHERN ROOT-KNOT NEMATODE
Applied Research
Blake Carter
County Extension Agent
University of Georgia Cooperative Extension Service
Springfield
Abstract
Vydate L was applied on a commercial carrot farm in Screven County, GA in a field which was infected with Meloidogyne incognita. Telone II (12.5 gal/acre) was applied preplant though field conditions showed lack of efficacy for unknown reasons. Carrots, seeded from 25 Sep to 1 Oct 2019, had stunted growth with nematode galls present on the roots approximately three months after planting. The trial was designed to have 3 treated plots directly adjacent to 3 untreated plots for side-by-side comparisons. Average number of root-knot nematode and stubby-root nematode (Paratrichodorus, spp.) before application of the nematicide was 2 and 8 nematodes/100 cm3, respectively. Two applications of Vydate L were made during the growing season on the 15 Jan and on 4 Feb 2020, just prior to rain events. Upon project completion, 1 foot of the twin rows from each bed was dug, carrots were washed and sorted by size and weighed. All treated and un-treated beds were rated on nematode galls on both tap root and fibrous roots at harvest. Three root samples were collected from each row and gall rating was done using a scale of 0-5. Soil samples (one composite sample per bed) were collected at harvest to examine the population density of the nematodes. No phytotoxicity was observed on plant foliage after first and second application of the nematicide. The population density of root-knot and stubby-root nematodes in nematicide treated plots were numerically lower but not significantly different than the nematode count in untreated plots. No statistical difference was found in carrot yield between treated and untreated plots treated with Vydate L in comparison with untreated plots. Although a statistical difference was not found, based on economic analysis we can see an increase in pounds and financial return. There was a 15.8% yield difference per acre for the large carrots. Overall, the systemic activity of Vydate suppressed root-knot nematode development in infected roots resulting in relatively better nematode control and lower yield loss.
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Authors: B. Carter, J. Mallard, A. Hajihassani
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Carter, B. County Extension Agent, University of Georgia Cooperative Extension Service, Georgia, 31326
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Mallard, J. County Extension Agent, University of Georgia Cooperative Extension Service, Georgia, 30467
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Hajihassani, A. Assistant Professor of Nematology, UGA Department of Plant Pathology, Georgia, 31794