b'severeblackheartdisorderoftenrots Herbicide Issues pHcancauseherbicidestobemorebefore emergence. Herbicide carryover in soil: Patterns of activeandincreaseinjurysymptoms.soilcarryoverwillhaveconsistent Some varieties are more susceptible toinjurysymptomsintheareasofthe herbicidessuchasmetribuzin.field or where the herbicide carryover isa problem. Issues can be in the entirefield or specific areas with higher herbi-cide carryover based on soil characteris-tics or previous herbicide application. Blackheartofpotatotuber.(JohnNordgaard, Black Gold Farms)Sprout Inhibitor Contamination Metribuzin damage to CalWhite pota-Chlorpropham(CIPC)contamination toplant.(AndyRobinson,NorthDakota State University/University ofin storage. The sprouts of seed contami- Minnesota)nated by residues of CIPC in storages arecauliflower-shaped and will not produce Chloroacetamide Herbicide Injuryplants.Herbicidecarryoverinsoil.(Andy Cool and wet conditions will increaseRobinson,NorthDakotaState plant uptake and prolong plant metabo-University/University of Minnesota)MaleicHydrazide(MH-30)residuesin lismcausingslowgrowthandmal-seedfromcontactduringprevious Herbicide Residue In Seed formed leaves. growingseason.MH-30suppresses Seed may not sprout, have cauliflower-sprouting and suppression of emergence likesprouts,and/orcandelabra-like The active ingredient metolachlor anddepends on the residue level and size of stemscausedbyherbicidescausinga dimethenamid can cause slowed emer-thetubers.Thelargerthetubersthe lossofapicaldominance,mostcom- gence. highertheconcentrationofresidues. monlycausedbyglyphosate.Residues decline with time and sprout Emergencewillmostoftenappearasdevelopment occurs, but growth is sub- scattered injury throughout the seed lotstantiallydelayed.Ifaccumulatedin planted with. Some plants will look nor-sufficientquantities,sprout-inhibiting mal; others will show varying levelingcompoundsmaycausedelayedemer- ofherbicideinjurysymptoms.gence of seed tubers.Chloroacetamideherbicideinjury.(Andy Robinson, North Dakota StateUniversity/University of Minnesota)Variety CharacteristicsErratic stand from glyphosate residueinseed.(AndyRobinson,North Apical Dominance Dakota State University/University of TuberswitheyesconcentratedattheMinnesota)budend(e.g.Ambra)orhavealowSproutsinhibitedbyCIPC.(Steve Herbicide Damage By Soil Type number of eyes (e.g. Bannock Russet). Johnson,UniversityofMaine Soils with low organic matter and highCooperative Extension)MAY/JUNE 2021 POTATO GROWER 21'