Growing Chestnut Trees

Ever wish you could have a crop that – with some initial tender loving care – could stand on its own each year? What’s more, you wouldn’t have to harvest it. Your customers would do it instead.

That’s the situation Tom Wahl and his wife, Kathy Dice, have. They grow mainly chestnut trees on Red Fern Farm near Wapello, Iowa. 

Chestnuts are to the nut world what soccer is to the sports world. They’re popular worldwide – except in the U.S. About 70% of Red Fern Farm’s customers are Bosnian; the rest come from China, Korea, Vietnam, Croatia, Laos, France, Germany, and Italy. 

“Locally, chestnuts are a niche market. On a worldwide scale, they’re the No. 3 nut in the world, behind coconuts and peanuts,” says Wahl. “Most nuts are used as garnishes, but worldwide, chestnuts are a staple food.”

Each fall, customers come to the farm to pick the fallen chestnuts. It’s a loyal customer base that’s grown mainly by word of mouth since Wahl and Dice began growing chestnut trees in 1992. “Some people will drive hundreds of miles to get here,” says Wahl. 

Early  TLC  Essential

Growing chestnuts is not as easy as it sounds, though. 

“When we first planted chestnut trees, we didn’t have the best genetics,” Wahl says. “We have gradually been removing poor trees and replacing them with better ones.”

Soil type is key. Chestnut trees require well-drained soils on the acidic side of the pH scale. Like row crops and small grains, chestnut trees have their share of pests. 

“Just like you can’t throw a corn seed in the ground and walk away from it, neither can you walk away from a chestnut tree,” says Wahl. “Deer and rabbits are, by far, the worst pests.”

Wahl and Dice place chestnut saplings into 5-foot-high shelters. “It helps trees grow and start producing nuts faster in two to four years vs. six to 10 years,” he says. The shelters also reduce the need for pruning. 

After five to seven years, though, it’s off to the races. Deer and rabbits no longer bother them. Meanwhile, the resulting tree canopy also shades out any weeds that formerly needed to be pulled. Chestnut trees can live 1,000 years, assuming they’re not struck by lightning or die from disease, says Wahl.

Then There’s This

This year, though, will be the first year Wahl and Dice have not had a chestnut crop. Chestnut trees can’t tolerate a precipitation-pocked year like 2019. Soils this spring started to dry following heavy 2018 fall rains. However, rain that eventually tallied 40 inches over 40 days began to fall in early May. 

“In early July, I thought we might lose 50% to 90% of the trees, but then they started putting out healthy-looking leaves,” he says. Although there will be no 2019 chestnut crop, he figures he will lose only 10% of the trees that he likely would have eventually culled. 

Another worry is off-target dicamba. In 2017, Wahl noticed widespread leaf damage. 

“The leaf margins were tightly curled, and I hadn’t seen that before,” he says. “It’s easy to confuse with potato leaf hopper damage. However, leaf damage from that insect curls forward. This damage curled the leaves backward.” 

Wahl believes his trees were hit by off-target dicamba. The farm’s trees had been hit by off-target chemicals before 2017, such as alachlor (Lasso) and metolachlor (Dual Magnum).

“When neighbors spot-sprayed thistle patches on their side of the property line, we were hit with phenoxy herbicides, probably 2,4-D,” he adds. “My trees that were close to the spot were affected.”

However, damage only crept in 50 to 100 feet along the property line.

The 2017 damage differed, as affected leaves were 10% to 15% smaller than unaffected ones. There was also a distinct difference in damage from one tree to another, which is consistent with phenoxy herbicides (like dicamba and 2,4-D), says Wahl. 

Dicamba in the form of Banvel and Clarity had undoubtedly been applied near his trees prior to 2017, he says. However, damage never surfaced like 2017, when dicamba formulations labeled for dicamba-tolerant soybeans could be used, he says. 

Wahl says he isn’t antichemical. He used to be a certified pesticide applicator, and he still uses herbicides. 

The good news is, it’s unlikely that any off-target herbicide damage was permanent, he says. Still, future use of phenoxy herbicides like dicamba and 2,4-D is a worry. 

What Could Pull the Plug?

If federal and state regulators pull the plug on dicamba use in dicamba-tolerant soybeans, it likely won’t be due to off-target damage to soybeans. They’ll be looking at other plants and trees, believes Kevin Bradley, University of Missouri Extension weed specialist. 

“In Missouri, people are noticing what is happening to their trees,” he says. “It is obvious. There are signs all over about dicamba injury.

“We have had complaints (about dicamba damage) to tomatoes, watermelons, vineyards, residential properties – you name it,” says Bradley. “When you start getting into trees, vineyards, tomatoes, and other crops, that will raise eyebrows even more than the (2017) damage on 3.6 million acres of soybeans.”

Specialty crop injury is high-dollar damage, says Larry Steckel, University of Tennessee Extension weed specialist. “If dicamba curls leaves on tobacco, you could lose a $10,000-per-acre contract,” he says.

In 2017, dicamba moved off-target through spray tank contamination, application in windy conditions, incorrect nozzles, and other factors. What also played a role, though, was volatility. 

“Volatilization (in Tennessee) was a primary mechanism for off-target movement in dicamba applications,” says Steckel.

For protection, Wahl planted a windbreak on the north side of his property where row crops are planted across from the farm’s trees. Still, he wishes the agricultural chemical industry would move in another direction. 

“What’s needed are herbicides that control weeds and don’t volatilize, and they aren’t going to do that with phenoxy herbicides like dicamba and 2,4-D,” he says.

Georgia experience

Farmers in Georgia have applied dicamba on dicamba-tolerant soybeans and cotton, just as farmers in other states have done. The difference, says Scott Partridge, Monsanto vice president of global strategy, is that Monsanto received no reports of off-target dicamba movement in Georgia in 2017. 

“Out of the 1,200 calls we got in 2017 regarding off-target dicamba, not a single one came from the state of Georgia,”
he says. 

Partridge says this was due to stringent mandatory application training on the then-voluntary restricted pesticide use label. 

“Training and education are absolutely important to making applications correctly,” he says. 

Georgia’s abundant vegetable industry also may have impacted the lack of off-target complaints, adds Larry Steckel, University of Tennessee Extension weed specialist.

That state’s farmers have typically been wary of spraying near them, he adds. “This was one of the points of emphasis in their Using Pesticides Wisely training.

“If an Xtend cotton field was near a cowpea field, they frequently used Liberty, not dicamba,” Steckel adds. “In fields of Xtend soybeans, they could often use Flexstar to control Palmer amaranth instead of dicamba near high-value crops.”

Unfortunately, using a PPO-inhibitor herbicide like Flexstar is often not an option in states like Tennessee. A recent survey showed 80% of Palmer amaranth in western Tennessee resists glyphosate and postapplied Flexstar. That’s why Steckel recommends farmers bordering high-value crops in areas of high PPO-resistant weeds plant Liberty Link soybeans and apply Liberty (glufosinate) herbicide. So far, no Palmer amaranth populations resist glufosinate.

“I know it is a hassle to grow both Xtend and Liberty Link soybeans,” says Steckel. “However, it would be better to suffer a little dicamba damage on your Liberty Link soybeans than to have to go through all the drama, time, and expense if the finger is pointed at you for drifting on a neighboring high-value crop.”

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