Production Blog
New Year, New Weeds
ST. LOUIS (DTN) -- The weed alert that popped into my inbox last week hit a personal note for me.
Farmers often struggle with (and I write about) weeds such as Palmer amaranth, marestail and kochia that grow far beyond my backyard experience. Burcucumber, however, is a familiar enemy.
In the summer of 2014, the clever look-a-like weed invaded my 15-by-15 garden patch in eastern Kansas and grew sneakily alongside my hard-working cucumber plants, undetected by this novice gardener.
It mooched nutrients and water for two months, until it dawned on me that I was tending a pretender. Like the cucumber plant, burcucumber is a nimble climber with star-shaped leaves and grasping tendrils. But the leaves are smaller, their texture smoother, and most importantly, the plants didn't flower at the same time as my industrious cukes.
Furious, I spent an entire afternoon untangling four imposters from my heavily branched cucumber patch. By the end, the garden (and I) looked a little worse for the wear, but the burcucumber was gone.
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Until... I noticed a dozen more plants lazily lacing their way along our fence. We were moving to St. Louis in a week, so I conceded defeat and went back to packing. Not long after our move to the Show Me state, University of Missouri weed scientist Kevin Bradley announced two new Missouri weed pests: toothed spurge and burcucumber!
I concede the timing is suspicious.
Burcucumber is surfacing in low-lying areas and along creeks and rivers, Bradley warned. "We haven't historically had a whole lot of problems with burcucumber in this state," he told Missouri growers at a university crop conference in December. "But just before harvest, my phone started lighting up about burcucumber. Be aware of it and watch for it."
Burcucumber might have been merely a nuisance in my Kansas garden patch, but it can reduce soybean yields by up to 48% and is difficult to control, Bradley warned in a University of Missouri press release. The climbing weed can also be a problem for corn growers when its serpent-like vines strangle and lodge corn plants.
My hand-pulling technique might get a little burdensome over hundreds of acres. So for farmers, Bradley recommends a pre-emergence application of either atrazine or a pre-mix containing atrazine for early season control. Fields with burcucumber are likely to need post-emergence applications as well, he noted in the press release.
Toothed spurge is also threatening to give Missouri farmers a new headache. This time, I'm in the clear. I've never seen this summer annual, which resembles wild poinsettia, but a lot of soybean growers in northwest Missouri did last year.
"It tolerates glyphosate, which is why we're seeing it," Bradley warned, so controlling the weed will be difficult. In a university weed guide, Bradley estimates that a single post-emergence application of glyphosate will only control 50% to 60% of toothed spurge. Instead, he recommends atrazine and isoxaflutole for pre-emergence control in corn, and suggests dicamba, glufosinate, and a tank-mix of bromoxynil plus atrazine for post-emergence control.
For soybean growers, Bradley recommends flumioxazin products for their good pre-emergence activity, and lactofen and a tank-mix of imazethapyr plus bentazon for post-emergence control, as well as glufosinate.
Whatever you do, try and control these two weeds before they become more prevalent, Bradley urged. I know of at least one future garden in St. Louis that is depending on it...
For more details on toothed spurge and controlling it, see Bradley's weed guide: http://goo.gl/…. For more information on burcucumber and how to control it, see this Purdue guide: http://goo.gl/….
Emily Unglesbee can be reached at emily.unglesbee@dtn.com
Follow Emily Unglesbee on Twitter @Emily_Unglesbee
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