b'Andys Advice:Checklist Of Potato Emergence ProblemsEugenia Banks, Potato Specialist, Ontario Potato Board, Andy Robinson, Associate Professor and Extension Potato Agronomist, North Dakota State University/University of Minnesota, Steven B. Johnson, Crops Specialist and Extension, Professor, University of Maine Cooperative Extension factorsinoptimizingcropemergence.This bacterium is found in all agricultur-Ideally,thesoiltemperatureandtheal soils and in surface water. Soft rot is seed temperature should be the same atfavored by free water and high tempera-planting; ideally 50o to 55o F (10o to 13otures.Softrotbacteriaarepresentin C).Assoilswarm,sproutgrowthtuber lenticels penetrate tubers through becomes most rapid at 68o to 72o F (20owounds or bruises. Fusarium infection of to 22o C). Favorable soil moisture shouldseedcanpredisposeseedtobacterial be in the range of 75 to 85% availabledecay. This can happen when seed pota-soil water. Seed treatments are availabletoes are left in a truck on warm days for toreducetheincidenceoffungal24 hours or longer or planted in warm pathogenssuchasFusarium,andwetsoil.Rottedtissueisbrown, HelminthosporiumandRhizoctonia,butmushy,slimy,watersoaked,andsur-not for bacterial pathogens.roundedbyablackmargin.Infected seed often has a foul odor and seed rots Slowemergenceoftenresultsfromquickly in the field leaving gaps in rows. plantinginnon-idealconditionsor At times, potato growers may experienceusing lower quality seed. But sometimes poor emergence of potato plants. Therea poor stand follows high quality seed are number of reasons why potato plantsandperfectplantingconditions.For may not emerge properly. This article isexample,plantinggoodseedinawet intendedtoprovidealistofcommonsoil, either hot or cold, favors bacterial problemsthatcancausepoorpotatosoft rot, which may result in poor stand. emergence and stand. Utilizing this listOr, planting good seed in ideal condi-can help growers more rapidly identifytions, a poor stand can occur because of the cause and improve management ofherbicide carryover in the soil or herbi-the crop and subsequent crops.cideresiduesintheseed.ThereareaTubersoftrot.(EugeniaBanks, number of ways that potato emergenceOntario Potato Board) Planting healthy seed is one of the mostcan be affected. The following checklist important factors that allow growers toof common factors that occur before orBlackleg (Pectobacterium atrosepticum)produce a high-quality and high-yield- afterplantingthatreduceseedemer- This pathogen is primarily seed borne. ingpotatocrop.Certifiedseedshouldgence. Rot starts at the stem end and extends give optimum emergence when handledintothetuber.Infectedfleshfirst and suberized properly especially keep- Checklist Of Problems That Causeappears cream-colored, but turns darker, ingtubersfreeofbruisesorinjuriesPoor Potato Emergence/Stand greyishblackandmushywithtime. wounds. Optimum soil conditions willSecondary bacteria that invade affected increase the probability of a successfulSeed Rot Caused By Bacterial/Fungaltubersgiveoffafishysmell.Planting plant stand. Pathogensinfectedtubersmayresultinseedrot Tubersoftrot(Pectobacteriumcarotovo- andpre-emergenceorpost-emergence Soiltemperatureandmoisturearekeyrum subsp. carotovorum) stem rot called blackleg. 10 POTATO GROWER MAY/JUNE 2023'