- Associated Press - Wednesday, June 29, 2016

LATROBE, Pa. (AP) - Neil Palmer does more than water his tomato plants to help them grow. He often sprays them with a copper-based liquid to ward off fungal infections that could impair their development and production.

“It’s not a foolproof method, but it can really protect the plants. It creates a barrier that is uninhabitable for fungus,” he said.

It’s one of the organic methods Palmer employs to control pests and diseases at his farm in Unity.

Farmers like Palmer, who prefer to avoid chemical treatment to boost their crops, have turned to such alternative measures as importing helpful microbes and constructing shelters to control the growing environment.

“Copper is often an organic way to go for a fungicide,” said Linda Hyatt, a horticulture expert with the Penn State Extension office in Westmoreland County.

She said the copper treatment can help protect plants against early blight and Septoria leaf spot - fungal diseases that can cause defoliation, affecting the yield of the crop.

“We see both of these every year because they overwinter in the soil in Pennsylvania,” Hyatt said of the fungi responsible for the diseases.

Palmer has found it impractical to meet federal organic certification standards for all the substances he applies to his vegetables and sweet corn. That gives him flexibility to use more extreme measures when warranted.

“We will spray a synthetic fungicide on our tomatoes if it’s a bad year,” he said. “We will opt to save the crop. Tomatoes are the biggest vegetable we grow.”

Vigilance and prevention are paramount, Palmer said. He scouts regularly among his more than 2,000 tomato plants, a magnifying glass at the ready to spot small lesions that could be a sign of disease, or pests like the striped cucumber beetle, a perennial threat to his zucchini crop.

“It will wipe out your plants if you let it go,” he said.

To keep the bug at bay, he invests in fabric screens to shield the plants.

Palmer does not grow as large a crop of onions, which are among plants in the allium family threatened by a pest that is expanding in the state.

He said he’s had no problem yet with that insect, which is a variety of the leafminer fly, but he has lost some plants to the onion root maggot.

“I just grow a little bit of it, so it’s not a big loss,” he said.

Paul Sarver, who has operated Sarver’s Hill Organic Farm near Greensburg since 1979, has used copper on crops but said he prefers to select hardy plant varieties and provide them with nutritious soil to help them withstand any threat.

“We’ve found that the Roma and plum tomatoes are more resilient to disease, so we’ll make sure we have plenty of those,” he said.

Sarver, who harvests about 40 tons of produce on 12 acres each season, improves his soil by adding compost and minerals and by rotating crops. He allows a break of multiple years between growing similar plants in the same spot so the nutrients in the soil can be replenished.

Instead of fabric covers, Sarver may apply diatomaceous earth to his crops to keep pests off. The chalk-like powder is made from the fossilized remains of the diatom, a single-celled organism. Scent is another important tool, he said, noting pheromones may be used to direct insects away from valued plants.

Like Palmer, Sarver relies on ladybugs to dine on aphids that otherwise would attack many of his crops. Sarver said he encourages aphids to lay their eggs on his flowering spinach plants to provide a food source that helps the ladybug population thrive.

Art King, one of three family members who operate Harvest Valley Farms in Valencia, relies on predator organisms and growing crops in protected tunnels to help shield his plants from pests and disease.

King has discovered leafminers at work on his spread. More so than onions, he said, they have caused trouble among his red beets and Swiss chard. He said the larva “feeds within the membrane of the leaf. It then drops down and crawls into the soil, pupates and comes out as a fly,” beginning the life cycle anew.

But he believes he’s got the pesky flies foiled since he began adding three species of nematodes to his soil. The microscopic worms feed on harmful pests, including the leafminer pupa.

“It’s one of the best things I’ve done,” he said.

In the spring, he purchases about 4,500 ladybugs, which start to reproduce in early summer as they dine on aphids in the high tunnels. Each tunnel is nearly 100 feet long and consists of a plastic membrane stretched over a galvanized steel frame.

“One of the benefits is my crops are not out in the rain,” he said. In times of frequent precipitation, they aren’t subject to the excess moisture that can invite disease.

Randy Morris has found success thwarting pests with organic strategies at his Irwin farm - primarily by providing nutritious soil.

Morris said it costs about $50 per acre to add organic material to soil. But he said it would cost hundreds of dollars to apply conventional chemical treatment over the same area. His approach has paid off doubly by providing resistance for his cucumbers against beetles, and for his squash against another insect, the vine borer, he said.

According to Morris, a nutritious diet bolsters the sugar content of his vegetables, making them more tasty for his customers but less than palatable to hungry pests.

“They don’t digest sugars very well,” he said. “They don’t thrive very well on healthy plants. It’s only the unhealthy plants these pests attack.”

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Online:

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Information from: Pittsburgh Tribune-Review, http://pghtrib.com

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