Navel Orangeworm Control in Pistachios

Consultant examines pistachio trees for navel orangeworm damage.

When it comes to navel orangeworm control in pistachios, a well-timed insecticide application is often key to protecting quality in this popular crop.

U.S. pistachio production is booming, largely due to additional trees coming into production. Between 2003 and 2005, 21,500 acres of trees were planted, and another 25,000 new acres were planted in 2007 alone.

Along with industry growth comes continued concerns about proper pest control to maintain product quality. At or near the top of the “worst pests” list for nut production is navel orangeworm (NOW). It’s the most damaging worm for pistachios, primarily at hull split.

Timing is Critical

“Timing is everything when it comes to NOW control at hull split,” says Todd Fukuda, tree nut consultant for Weinberger and Associates, Hanford, California. “Once you’ve missed it, and you’ve got worms in the nuts, you’re in trouble. Most of the recent research seems to be pointing toward making an insecticide application a little earlier than in the past, so we’re leaning toward that.”

Fukuda adds that the industry threshold for pest damage to pistachios is just 0.5 percent at harvest. “So if damage gets up to the 2 or 3 percent levels in a crop, it’s bad.”

Navel orangeworm control in pistachios is not just a production concern for growers, but an industry concern, notes John Jenkins, retail account manager, DuPont Crop Protection. “NOW damage at shell-split not only impacts nut quality, but could invite aflatoxin, which is a health concern for consumers. The pistachio industry can’t risk that kind of negative market impact when it comes to food safety.”

NOW Control Strategies

Choosing appropriate pest control products and making timely applications is critical to protecting valuable nut crops, especially when exceptional yields are expected.

Products such as DuPont Altacor® insect control powered by Rynaxypyr® can be effective options. Altacor® protects crops from NOW and other damaging pests and optimizes the potential to produce high-quality, high-yielding crops.

Jenkins stresses the importance of crop protection technologies that improve field spray efficiencies. “Although there are many application and orchard variables to consider, keeping the ground sprayer speed below 2 miles per hour is a critical component to a good application technique. You’ll get better performing insecticides with fuller coverage during hull split.”

Another key way to gain additional overall field efficiencies is with products that have the shortest re-entry and pre-harvest intervals. “Application timing is so critical with NOW and a few days can make a huge difference, notes Fukuda.”

Long-lasting control is a key component to any pistachio insecticide program. “We look for products that have long residual control and are compatible with other products,” says Fukuda. “Tools need to fit not only into our integrated pest management (IPM) plans but need to help us preserve this high-value crop from the ever-present NOW.”

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