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Preharvest Treatment Useful Tool in Battling Birds

Saturday, December 1, 2007
filed under: Birds

Brothers Kevin and Kent Matejcek found a new ally this year in their annual “battle with the birds” — a preharvest application of glyphosate.

The Matejceks, who farm near Lakota, N.D., are the only sunflower producers in their immediate vicinity — a vicinity that includes substantial CRP acreage and plenty of cattail-populated wetlands. They aggressively fight blackbirds on their own land; but can’t do much about bird habitat on their neighbors’ CRP. “There are a lot of nearby roost areas we can’t manage,” Kevin affirms. As a result, the Matejcek sunflower fields show up on bird radar as a very alluring food bank.

In recent years, the Matejceks have utilized the cost-share program wherein USDA-APHIS covers up to 70% of the cost of chemical control of cattails in standing water. This year, they also participated in the conservation “lure” plot program under which USDA provides cost-share funding for the planting of plots in high-damage areas. The Matejceks planted a total of 60 sunflower acres (three sets of 20) in lure plots last spring, mainly along the edges of fields located next to cattail marshes.

The lure plots “really helped us,” Kevin reports. “Birds like to work on those edges from where they’re roosting.” Feeding heavily in the lure plots, the blackbirds did minimal damage to the Matejceks’ adjacent confection sunflower acreage.

Those confection acres received the glyphosate treatment in early September. Kevin and his agronomist actually threshed out several heads, tested seed moisture and found it to be right around 35%. The aerial applicator made the Roundup application the following day. It took about three weeks for the seeds to drop down to their targeted harvest moisture level; but the Matejceks were still able to roll their combine into the field a good week to 10 days earlier than had they not treated. That earlier entry translated into a significant reduction in seed loss due to avian marauders.

George Linz is as familiar as anyone with the problem of blackbird depredation in commercial sunflower fields. The USDA-APHIS Wildlife Services research biologist has invested about 30 years studying the issue and developing recommendations on how to reduce blackbird damage.

So does Linz believe a preharvest application of glyphosate can be a helpful tool in the ongoing battle with the birds? “Yes, I don’t think there’s any question,” he affirms.

The Bismarck, N.D.-based biologist points to 2007 as a good example. “The birds really stayed late this year” due to relatively mild temperatures and absence of October/early November snowfall, he points out. “There’s no reason for them to go as long as there’s food available and the ground is not covered. Once you get snow on the ground, they leave; otherwise they’ll stay a long time.”

That scenario spelled trouble for numerous late-harvested sunflower fields. “Those who used [glyphosate] got their crop off,” Linz continues. “And the birds went to what was left. If you had a later crop this year — say rain delayed your planting and you didn’t have a chance to use the glyphosate in September — boy, those fields took a good hit” from blackbirds.

Linz is fully aware of the length of time it takes for preharvest glyphosate to work — especially in cool temperatures. But as long as growers plan ahead with that in mind, he believes it’s a very cost-effective tool for growers expecting to contend with significant bird damage.

For those who want to get their sunflower off as soon as possible, paraquat or sodium chlorate are definite treatment options. They’ll work much quicker than glyphosate. A downside with paraquat, however, is that should it rain following treatment, the sunflower head tends to absorb the moisture quite readily, slowing drydown and putting the plant at risk for head rot diseases.

For Linz, the two most important steps in reducing seed loss to blackbirds are (1) reducing cattail populations and (2) getting the crop off as soon as possible. “Those are the ‘bookends,’ ” he states. “That’s going to be our mantra this year as we go out to grower meetings.” Use the other techniques also available, such as propane cannons and lure plots, he advises. But when battling the birds, place top priority on setting up those two primary bookends. — Don Lilleboe
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