b'ROUNDTABLE When Herbicides are Bad How to identify if your spuds have herbicide injury and what to do once its confirmed. BY: ASHLEY ROBINSONANDY ROBINSON Editors note: This interview has beenSS: How do you identify that a extension potatoedited for length and clarity. potato plant has been injured by an agronomist at Northherbicide?Dakota State UniversitySpud Smart (SS): Why is herbicideVB: One of the important things is for and University of Minnesota injury a concern for potatopeople to become familiar with the growers? foliar symptoms of commonly used Vikram Bisht (VB): Non-target herbicideherbicides in your areait is also helpful VIKRAM BISHT injury is a frequently occurring issue into understand what is the distribution plant pathologist formany crops. Potatoes are particularlypattern. If the symptoms of the injury are potato and horticulturalsensitive to many herbicides used in thefading away from the edge of the field, crops with Manitobacrops surrounding potatoes.it is possible that theres drift associated. AgricultureThere is a cost of herbicide injury toThere may be other ways to understand potatoes, which could be very negligiblehow the drift happened. The affected or be very severe losses. On commercialplants are randomly distributed in a field crops, the losses are in yield reductionit is possibly a seed carryover. And often and tuber quality. But on seed quality,the concentration in zones could be a soil the losses can be very significant due toissue. possible rejection of the seed lots. AndNow, there are some cases where it could also become a problem for nextthere is no visible injury. This may year. There are possibilities of litigationhappen when the herbicide that has resulting from severe herbicide injurycome onto the crop is at very, very low losses, especially for seed growers.concentrations or late in season. There are cases, where for example, glyphosate SS: How does herbicide injuryhas been used on some field crops for happen on potatoes? weed control, that is pre-harvest dry VB: Herbicide injury is possible throughdown, there is a late season exposure. various ways. Drift from the nearbyUnfortunately, in many cases, the injury applications under various conditions,to the seed lot is not detected by the post-which favour the spread of the appliedharvest testing that is done for viruses material, whether it is too windy, there is noin the labs. And so, one of the important air movement. Improper nozzles have beenthings if there is suspicion that there may used for the conditions making very finehave been some herbicide injury on to the mist, air temperature inversions can be anseed crop, it is good to get a grow out test issue and proximity to the sensitive crops. that is where you will possibly catch Improperly cleaned sprayer tanks cansome of the herbicide injury issues.be an issue in many cases, misapplications of product in a field or a wrong productAndy Robinson (AB): Typically, youre in a fieldthis happens quite often.going to visually see injury in the leaves. Mistimed application of herbicides when,Sometimes you might see injury in the for example, the applicator sprays whentubers, sometimes you wont. It depends ROUNDTABLE SUPPORTED BY: the plants are already emerging or thereon the environment, the timing, and the are ground crack from emerging sprouts.product that comes in contact with the Also, soil residue is a big issue in someplant. There are many things you should cases, and important to understand howlook at to diagnosis herbicide injury, it happens. Sensitive varieties to alreadyincluding field pattern, plant symptoms, registered products on potatoes are anand areas adjacent to the fieldissue that happens sometimes.If youre not comfortable with making 40SPUDSMART.COM Winter 2023'