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Packing on the Pounds

Sunday, January 18, 2004
filed under: Optimizing Plant Development/Yields

Vance Huse started growing sunflowers on his farm near Onida, S.D. in the 1970’s, and ever since, ‘flowers have had a place in Huse’s crop rotation that also includes winter wheat, milo, corn, and spring wheat.

Nearly 30 years of growing sunflowers have given Huse plenty of experience to draw from in producing the crop. Still, problems arise that can be tough to manage. Stem weevils, for instance.

“They just killed me in 2002. I still had a decent crop, but on about 25-30% of my acres, I lost about 50-60% of the stand from tipping over late in the season.” He was also having problems with palestriped flea beetles, which have been giving some sunflower growers in South Dakota early-season troubles the past few years. (See a backgrounder on the pest online:

So in 2003, Huse decided to try Furadan 4F (Carbofuran) at planting. The product can be mixed with water or liquid fertilizer, and applying it in-furrow with the seed doesn’t hurt seed germination or seedling development.

Furadan 4F is systemic, translocated in the plant through root uptake, with residual effectiveness of about 45 to 55 days, depending on moisture, soil microbial activity, and other factors. Soil moisture will affect treatment uptake and residual effectiveness more than temperature. The product helps control early-season insect problems, such as wireworms, sunflower beetles and early-season grasshoppers. And for Huse, the product delivered.

“In the spots where we had problems where a hose plugged or a wire broke and the Furadan quit, flea beetles and wire worms absolutely wiped me out. We had to replant every acre where we didn’t put the treatment on, so I was really impressed with it. And the residual puts you right into the stem weevil season. If it’s helping to control stem weevils, which were killing me the year before, than it’s probably worth the cost.”

Huse normally shoots for a plant population of 22,500 seeds/ac. He notes that the treated sunflower maintained a population of over 22,000 plants/ac, while the untreated fell to a range of 15,000 to 18,000 plants/ac.

Sam Tutt, northern technical manager for FMC Corp, which makes Furadan 4F, says the product’s chemistry has been around for decades, and continues to be a good tool for fighting insects, especially for crops such as sunflower, with limited treatment options.

Furadan 4F is available from chemical retailers in returnable 15 gallon “kegs” for closed-system handling to reduce exposure to the user. The restricted-use pesticide can also be applied as a post-emerge foliar application, which also offers systemic control.

Tutt points out there are two weevils types: 1) the spotted stem weevil, the most widespread of the two; and 2) the black stem weevil, whose feeding makes sunflower plants more vulnerable to fungal diseases, but generally results in less plant injury or lodging than feeding from spotted stem weevils.

“The challenge with stem weevils is that the adults lay eggs over a wide period of time, and it can be very difficult to control them with a foliar treatment because of that. The good thing with a systemic product is that whether you apply it in-furrow or post-emerge and regardless of whether you plant early or plant late, you get the longer-lasting residual control.”

Another insect called the soybean stem borer (also called the long-horned beetle, or Dectes stem borer) has affected sunflower in some areas of the Plains, including South Dakota, and can result in similar stem feeding damage. Researchers are studying the effects of the insect in sunflower, including possible control measures. The efficacy of Furadan in controlling the stem borer in sunflower isn’t determined at this time.

Planting later than most

Huse plants his sunflower later than most. “We don’t start planting sunflower until about June 5 or 6, and finish around June 20 or even as late as June 23. All of our later-planted ‘flowers have always been 500 to 700 pounds better than the early-planted.”

General recommendations for sunflower planting in South Dakota is mid May to early June. South Dakota State University research indicates that oil is generally more affected by late planting than yield. Oil content generally begins to decline in sunflower planted after June 15, and yield generally begins to drop in sunflower planted late June.

Huse acknowledges that while other growers find success with early-planted ‘flowers, later planting suits his operation best. “I’m growing for maximum yield, and less for oil. We grow a lot of Kaystar 9501s, and the oil isn’t as good as you’ll find in others, but they yield well. We market about 85% of our sunflower for the birdseed market, and the rest for oil. I prefer full-season hybrids; the bigger the better as far as I’m concerned.”

By planting later, Huse believes his sunflower crop has a better chance of escaping insect pressure. With stem weevils, for instance, research has shown that delayed planting is effective at lowering larval densities in stalks in both the northern and southern Plains. There is an indication that more mature plants (earlier planted) may be preferred by weevils for egg-laying.

Huse also believes that a later bloom helps the crop avoid the hottest period of the summer, thus helping crop moisture use. He says a later harvest generally hasn’t been a problem. “I find that planting two to three weeks later than average will be about a week to 10-day difference at harvest. The only time I’ve had trouble is when I’ve planted into July, and I got a little frost damage, but even those did 1,600 pounds.”

Huse’s sunflower in 2003 ranged in yield from 1,300 to 2,400 lbs, with an average of about 1,700 lbs. “It was actually pretty good, given our dry conditions,” he says. “Any moisture we got, we used every drop of it. I felt this year’s crop had the most yield potential of any ‘flower crop we have grown. The heat and dry weather hurt. But in one field where there was a lot of low ground and adequate moisture our yield monitors went over 4,300 lbs/ac. I have never seen that kind of yield before. We just needed a little more rain.”

Last spring he applied 50 lbs of nitrogen, shooting for a yield goal of 2,400 lbs, fertilizing based on soil test recommendations. He used Spartan and Dual Magnum in 2003 for control of later-season grass and small broadleaf weeds. He put Spartan down two to three weeks before planting for small broadleaf weed control.

Delayed planting seems to help with kochia control, Huse notes, allowing him to back off on the rate of Spartan. Just before the ‘flowers emerged, he followed up with an application of Dual Magnum and glyphosate. He spot sprayed Poast for grassy weeds in low areas of a few fields.

In 2002, he experimented with Birdshield, a bird repellant made from grape juice. “We applied it to sunflower by a slough and it worked good, cutting damage back by about 70%.” He didn’t put any down in 2003, however, since birds weren’t much of a problem. “There are certain areas I won’t plant ‘flowers because of birds, but there sure seemed to be fewer of them this year.” He speculates that with dried-up stock dams and sloughs in the drought-stricken area, birds didn’t stick around and moved on to areas with standing water. - Tracy Sayler

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