b"Shrinking ToolboxWith fewer pesticides available to control insects and disease, potato growers in Canada need to find new options for protecting their crops.BY: MARK HALSALLIN RECENT YEARS, the loss of a number of important pesticide products as well as new restrictions on the use of some others has meant potato growers are having to think outside the toolbox to protect their crops from harmful diseases and insects.Among the latest pesticides to be removed from the market is bifenthrin (Cap-ture), which is utilized extensively in Canadian potato fields to combat wireworms. Back in 2017, Health Canadas Pest Management Regulatory Agency (PMRA) or-dered a three-year phaseout of the insecticide with the last date of sale permitted by retailers as Dec. 31, 2019. Potato growers can continue to use bifenthrinbut only until the end of this year.In 2015, the PMRA ruled phorate (Thimet 20-G), the other main control tool for wireworms on potato farms, was acceptable for continued use in potatoes.Theres also been changes regarding chlorothalonil and mancozeb, the popular broad-spectrum fungicides which form the core of late blight and early blight management in potatoes. The PMRA has placed new restrictions on chlorothalonil, including reducing the number of applications per year to three, but its still available to potato producers. Mancozeb is currently under review by the PMRA with the final decision on its use expected this summer. Some in the potato industry believe theres a good chance tight restrictions could be placed on the fungicides use, or mancozeb could be eliminated altogether as a crop protection option. New Brunswick Dave Bell, an agronomist based in New Brunswick, believes the implications ofagronomistthe recent PMRA re-evaluation decisions havent completely sunk in for many po- Dave Bell.tato producers. I don't think growers have fully felt the impact of these products being phased out and (understand how quickly) we're going to change the tools that we have to work with, he says.With fewer tools available in their crop protection toolbox, growers face not only higher costs of production and increased resistance pressure, but theSpore trapping systems designed to detect potato pathogens, like the late potential for regional crop devastation if through lack of choice more producersblight warning system in New Brunswick and Maine which benefits growers on both are using a similar control program and the pests develop resistance to the fewsides of the border, are one example, Bell says. products that are available, Bell adds. Biological pest control products, which enhance a plants ability to protect Another consequence is that when growers must use other products thatitself from disease, are another area showing a lot of promise, he says. They control a single disease, rather than a group of important pathogens, secondaryinclude Lifegard WG, a new broad-spectrum biopesticide spray which can control diseases can be left unchecked, resulting in reduced yields. late blight and early blight in potatoes.Bell notes as more restrictions are placed on broad-spectrum fungicide andBell notes while theres widespread concern in the potato industry about the insecticide products, other control measures such as scouting, insect monitoring,latest spate of PMRA re-evaluations, many acknowledge theres an upside to being disease detection and integrated pest management will become increasinglyless reliant on pesticides. important. It's also going to push us to do a better job and push us to employ other I think these methods are going to have to be employed more and more as wemethods rather than just reaching for that jug of prophylactic pesticide, he says. go forward, he says. Nobody likes to have to change, but a change in the long run could be good. 12 SPUDSMART.COM SPRING 2020"