Dry bean growers better be ready to make more than one pass if they’re trying some of the new post-hail recovery products to fend off blight.
“There are products registered, but they’re registered for multiple applications, so if you’re just spraying something on a crop as a one-off, you probably won’t see that yield benefit,” Dennis Lange, provincial pulse specialist, said. “You may need to look at if you want to go down that route, doing multiple applications.”
Why it matters: Bacterial blight often adds insult to injury after hail, but hail recovery products have yet to prove their yield benefit with a single application, and multiple applications are largely lacking data so far.
There are two types of post-hail recovery products, hydrogen peroxide or copper based, currently on the market. Both are typically used in the organic industry, although conventional farmers have since tagged the products as a potential bane for blight after leaves have suffered hail damage or other wounds, making them vulnerable to infection.
Lange pointed to North Dakota trials testing single application of four copper-based products (Kocide 3000, MasterCop, Badge SC and ET-F 2017) and two peroxide-based fungicides (Oxidate 2.0 and Sanidate 12.0, both offered in Canada through chemical company Plant Products in Eastern Canada).
Not all of those copper-based products are registered in Canada.
Treated plots did, in fact, appear more vibrant after application, those trials found. Trial data showed an immediate decrease in blight symptoms, dropping over 10 per cent in the worst per- forming product, and over 20 per cent for ET-F.
Seventeen days later, however, both hydrogen peroxide-based products showed little difference from the untreated plot.
That visual improvement did not translate to yield however, and Lange pointed to other trials in Ontario that did not even find visual difference after treatment.
Lange is now looking for Manitoba-based results from trials in Carman.
How many passes?
That answer will be highly reliant on the weather, Lange said. A dry season will have little risk of bacterial blight, and producers may want to consider that low risk before investing in a multiple application product. Even the recent combination of rain and hail may not spell bad blight if weather turns hot and dry, he said. Future wet weather, however, will raise disease risk.
Oxidate 2.0 is registered for up to eight applications although other products, such as copper-based Coppercide WP through Loveland Products, have no maximum application limit.
“Both trials that they’ve done so far have been single application of some of these products, whether it’s a copper-based product or whether it’s a hydrogen peroxide-based product,” Lange said.
Beans can recover from blight if damage happens early in the season and growing conditions are good, he said, although damage after flowering is a different story.
Lange urged anyone testing these products to leave a test strip to confirm the treatment’s actual impact.
Hail recovery products have sparked interest with growers, according to the Manitoba Pulse and Soybean Growers.
Production specialist Cassandra Tkachuk says she has yet to work with any growers using the products, but the commodity group’s on-farm network has got inquiries on future trials. Oxidate, in particular, has garnered interest, she added.
“Bacterial blight in dry beans is definitely an is- sue at the top of dry bean growers’ minds because there’s nothing you could really do about it until these products came along, but from what I have learned, we can’t definitively say that these products will control bacterial blight,” she said.
Tkachuk argued that more testing is needed to confirm efficacy, particularly in Manitoba conditions and with multiple applications.
Dry beans are a high-value crop, something that might entice farmers to invest more on inputs, she noted, but also noted that there is little data supporting the economic or productive viability of multiple applications of these products.
“It’s definitely worth testing on farm,” she said.
She urged interested producers to contact the commodity group’s on-farm network to set up their own trials.
Nitrogen management may fill a similar function by boosting growth after hail, Lange also suggested. Experts have typically recommended 100 pounds per acre of available nitrogen for a 2,000-pound-per-acre crop, recommendations based on North Dakota.
Local research by the University of Manitoba’s Kristen MacMillan, however, suggests that major yield jumps don’t occur until there is 140 pounds per acre of available nitrogen in the soil.
That work has been done recently in some of Manitoba’s driest weather in recent history, and Lange said he would be interested to see if that high nitrogen guideline holds up in wetter conditions.
“I guess the moral of the story is you need to know what your fertility is like… maybe bumping that up a bit might keep your plants greener longer and healthier and able to withstand issues that you might have with bacterial blight in the season,” he said.