b'tuber or in the bag will not cause a false- for will save time and money. Once spe- tested for was not present in the sample positiveresult.Ifsamplesneedtobecific test(s) are determined, fill out theorbelowthelevelofdetection.The stored overnight, place samples in refrig- laboratorys sample submission form. Ifnumerical values of a positive detection eration until they can be shipped. Shipunsure of what to sample for, there areare difficult to associate with yield loss, samples to the laboratory in an insulat- multiple compound testes available thatbut confirms the presence of the herbi-ed box with ice using nextday shippingcan be requested. cide.to keep sample integrity.When trying to select what herbicide toOccasionallysymptomsareobserved, Seed Tuber Samples testfor,lookforsymptomscausedbybutnodetectableherbicideresidueis At times, potato seed tubers that are pur- specificmodesofaction.Utilizinganfound in a sample. This could happen chased for planting can appear to haveherbicide mode of action chart can help,becausethecorrectchemicaltestwas herbicide injury and you may want tosuchasHerbicideInjuryinPotatoes,not performed, the herbicide compound havearesiduetestcompleted.InthisNDSU Extension article A1949. Or dis- wasbrokendownbecausesampling scenario,selectaboutadozentuberscuss the problem with an Extension per- occurred too late, or poor handling of that appear to have the greatest symp- sonnel, agronomist, or consultant. Testthesampleoccurred.However,some-toms(sampleA);typically,malforma- forthemostlikelycompoundandiftimesnopositiveherbicideresultsare tions or cracking is observed. As a checkthat comes back negative, another testfound because plant symptoms were a also sample about a dozen good lookingcan be requested (this is one reason whyphysiologicalresponsetoanon-herbi-tubers (sample B). Gently wash soil fromthe sample size is large, providing mate- cide stress. tubers and allow to air dry. Place tubersrial for subsequent testing).in a bag with the date and sample iden- Sampling for herbicide injury in potato tification. Contact the laboratory priorAnalyses Resultsplantsisimportanttoprotectthe to shipping to ensure they can performAfter analyses, a report will be generatedintegrity of the potato crop and grower. the requested test in a time frame thatindicating if an herbicide is detected andFollowing the outlined steps will ensure will allow a decision to be made beforeat what quantifiable amount. A positivethe most accurate diagnosis.planting that seed lot. Fill out the labo- detection confirms the presence of thatratoryssamplesubmissionformandcompound,whilearesultbelowthe ship the sample. If time permits, selectlevel of detection indicates the herbicide about 50 malformed tubers and 50 good tubers, and grow them in a greenhouse or office to see if any herbicide injury symptomsarevisible.Ifpossible,find the same variety from a different lot and grow out 50 tubers as a check.The Insulation Place14770 69th Place NEGrafton, ND 58237 What Test To Request Herbicide injury can often be perceivedUrethane Spray-On Insulationbut selecting the right test can be theEliminates air infiltration & stops condensationmostchallengingdecision.Thereare Highest R-Value InsulationFire Proofinghundreds of compounds that can cause Moisture BarriersFlat Roofschemical injury, and many have a differ-Grafton(701) 352-3233 1-800-352-0620enttestingmethodology.NarrowingBismarck(701) 255-0025 1-866-425-0025down the most likely herbicide to testWebsite www.theinsulationplace.comMARCH 2022 POTATO GROWER 21'