b'standardprogram(Fig.2B).Here,tivity testing must remain an ongo- https://www.ndsu.edu/agriculture/aprogramsutilizingProvysoleitheringfocusandtheevaluationofg-hub/publications/north-dakota-prior to row closure or at tuber bulk- fungicidesinthedevelopmentalfield-crop-plant-disease-manage-ingprovidedthebestdiseasecon- stages under field conditions in thement-guide. trol, but these programs were onlyregion are critical for the successful significantlybetterthanthepro- managementofearlyblightandThese trials are possible due to the gram utilizing Priaxor (2), Revus Topotheryield-robbingdiseases.work of Dean Peterson, Russel Benz (5), and Scala (7). Similar trials wereReducedfungicideefficacycanandtheexcellentcrewtheyman-conductedin2021,withsimilaroccur in the field for several reasons;age.results.however, it you feel as though you are not seeing the early blight con- The NPPGA and MN Area II potato As previously stated, reduced sensi- trol you have come to expect from agrowersgenerouslysupportthese tivitytoDMIfungicidessuchasspecific fungicide, please contact usefforts through funding the irrigat-RevusTopandQuashhavebeento discuss the need to evaluate fored research site near Inkster, North detectedinourregionbyourfungicide resistance in the lab andDakota.Thefieldtrialsreported researchprogram(Fig.3).Atthegreenhouse.herewerealsosupportedbyBASF. timethisreducedsensitivitywasDMIfungicideresistancestudies detected,manypotatogrowersinForacompletelistoffungicidesweresupportedbySyngentaand the region were using the maximumlabeled on potatoes, please see theValent. amountofactiveingredientofNorthDakotaFieldCropPlant Revus Top allowed on the EPA labelDisease Management Guide (PP622-(four applications of 7 fl oz/a for a22,RevisedJanuary2022)at totalof28floz/a).Thepotato industrywasmadeawareofthe reduced sensitivity to Revus Top and NDSU recommended that no moreBORON than two applications of a DMI fun-gicide be made in any one growingENGINEEREDseason.Oncethepotatoindustry acceptedthoserecommendations,TO DELIVERthe A. solani population returned to its original level of sensitivity (Fig. 3).BasedonFRACrecommenda-tionsthatcross-resistanceamong DMI fungicides should be expected, NDSUstillrecommendsthatthe numberoftotalapplicationsofA KEY MICRONUTRIENT AT THE RevusTop,Quash,andProvysolRIGHT PLACE AND TIME FOR SUCCESS.combinedshouldcontinuetobe limited to two in a single season.For potato yield data, please scan this code.Visit AspireBoron.com to learn more or Years of research have gone into thecontact your local retailer.developmentoffungiciderecom-mendationsforgrowersinthe region. For these recommendations 2021 The Mosaic Company. All rights reserved. to remain effective, fungicide sensi- Aspire is a registered trademark of The Mosaic Company.12 POTATO GROWER MARCH 2022'