Plan Ahead for Late-Season Navel Orangeworm Control

Navel orangeworm control helps protect yield during late pistachio harvest.

With strong consumer demand and high commodity prices, California pistachio growers intend to harvest as much of their crop as possible. This desire to maximize pistachio production has led to more double shakes and a harvest season that stretches into mid-October.

While a later harvest helps capture more tonnage, it also brings increased threat of navel orangeworm (NOW) damage as multiple generations have more time to develop over the longer season. And this year’s weather conditions have pushed NOW populations to extremely high levels.

“Our dry winter resulted in much higher NOW survival rates, and this season’s warm temperatures have accelerated population development,” says Joel Siegel, USDA, San Joaquin Valley Agricultural Sciences Center, Parlier, Calif. “With populations exploding earlier and extended harvest, growers need a navel orangeworm control strategy that provides sufficient protection longer into the fall.”

Three-Spray Program Extends Navel Orangeworm Control

Heavy NOW pressure has caused many growers to consider a three-spray insecticide strategy with alternating modes of action to protect valuable pistachio crops.

“Under a three-spray program, the first application is made around July 15 to knock down the population early in the season and prevent buildup of NOW populations,” says Siegel. “The second spray is applied in early August and the third spray follows in early September.”

He notes that activity from late applications with pyrethroid insecticides may not provide enough protection. “Growers need to rotate to alternative chemistries such as diamides for longer-lasting protection, but they must consider preharvest interval when planning applications.”

Altacor® insect control powered by Rynaxypyr®, an anthranilic diamide (Group 28) insecticide, provides effective, long-lasting control of NOW and most other economically important lepidoptera and selected other species.

“Altacor® provides long residual and ovicidal, ovi-larvicidal, larvicidal and adult activity on navel orangeworm,” says Jeff Pacheco, technical sales agronomist, DuPont Crop Protection. “It’s an important part of an effective navel orangeworm control program.”

Resistance Management Is Key

For resistance management, Siegel and Pacheco recommend growers avoid treating successive NOW generations with the same insecticide or insecticides that have the same group number.

“Sole reliance on inexpensive pyrethroids is going to backfire in the long run,” Siegel explains. “Last season, farmers who used some pyrethroids back to back didn’t get the necessary control, which cost them at processing.”

“The strength of new chemistries, such as Altacor®, and insect growth regulators, is that they last a long time, with excellent larvicidal and egg activity,” says Pacheco. “We also have evidence that Altacor® has adult activity under certain conditions, which provides additional advantages over other products.”

Always read and follow all label directions and precautions for use when using any pesticide alone or in tank-mix combinations.

In line with Integrated Pest Management and Good Agricultural Practices, insecticide applications should be made when pollinators are not foraging to avoid unnecessary exposure.

The information provided on this website is for reference only. Always refer to the product labels for complete details and directions for use.