b'spring, begin scouting early and use degree daysAnother thing Ontario is keeping an eye on is to determine potential emergence of the pest ina late blight look-a-like, Phytophthora nicotianae, order to know the best time for control interven- which is a related species to the late blightPotatosuffering fromtion, advises Noronha. pathogen P. infestans. This is more of a soil-bornelate blight. disease but can exhibit similar foliar symptomsPHOTO: RICKP.E.I. GROWERS EMBRACINGto late blight and was found in North Carolina inPETERS/AAFCADAPTIVE MANAGEMENT PRACTICES 2018, and New York and Pennsylvania in 2019.High priority diseases from recent years, includingLuckily Ontario did not have a major outbreak PED, common scab, blackleg (Pectobacteriumof late blight in 2019 so there were no real signs spp.) and Alternaria spp. (solani and alternate),of late blight or its lookalike, says Van Dyk.will plague potatoes again this year according toLate blight is an annual concern in Ontario a recent survey of plant diagnostic services doneand the late blight spore trapping network across by P.E.I.s Department of Agriculture and Land,the province has been critical for helping growers says Lorraine MacKinnon, the departments potatoto stay ahead of this disease and utilize their industry coordinator. fungicides preventatively.Last year was dry in July and most of AugustWith Dickeya blackleg being an emerging in the region, before being excessively wet inseed potato concern, growers should continue to September and October. Foliar diseases like lateprevent infected seed lots from being planted.blight, brown spot and early blight were either non-existent or mild. The winter of 2018/2019 sawLONG-TERM RESISTANCE PLAN a lot of freezing and thawing throughout, whichNEEDED FOR CPBeliminated a lot of volunteers and reduced seed- CPB resistance is once again on the radar in borne disease inoculum. Ontario. Neonic seed treatments still provide A number of P.E.I. growers are now employinggood control of CPB but recent resistance testing management software to predict pest and diseaseby AAFC has shown a growing tolerance to these risk in order to target pest management practices,insecticides in some populations. says Barrett. For many diseases, planting cleanA long-term resistance management program seed with proper preventative seed treatments isis going to be key for continuing control of CPB, a key to preventing diseases and pest issues laterespecially in the face of potential use cancella-in the growing season, he says. tions, says Van Dyk.Most island growers are aware of the localOntario has had a relatively mild winter which research that has been underway regardingoften means higher disease and insect pressure pest management on some of the most commonthe following year. We are also anticipating a pest and diseases, and are adapting productionhigher survival of volunteer potatoes which are practices or crop rotation to minimize their risk. potential sources of late blight, says Van Dyk. For example, we are seeing a large number ofHopefully the mild winter means that growers potato growers adapt their crop rotation to includewill be able to get an early start on planting as species like brown mustard, sorghum sudangrassopposed to 2019, but of course its still too early or forage pearl millet to battle Verticillum and rootto tell.lesion nematodes. Field scouting is a critical part of pest management, emphasizes Van Dyk. Know whats LATE BLIGHT LOOK-ALIKE COULD BEgoing on in your fields and adjust your manage-ON ITS WAY TO ONTARIO ment accordingly, he says. Know your pesticide Late blight remains a top threat for Ontariogroups and have a resistance management plan growers with vigilance in field scouting andin place, especially when it comes to late blight preventative fungicide applications required, saysand CPB. When late blight has been confirmed in Dennis Van Dyk, vegetable crop specialist withyour area or the risk is high, ensure youre apply-the Ontario Ministry of Agriculture, Food and Ruraling late-blight specific fungicides.Potato sufferingfrom fusarium dry rot. Affairs. PHOTO: KHALIL I.A new late blight strain, US-25 was detectedAL-MUGHRABInext door in New York State in 2018, so sending late blight for strain identification is very impor-tant, adds Van Dyk. SPRING 2020 SPUDSMART.COM 27'