Mating Disruption For NOW Works

Trials Show that Mating Disruption Works Well to Offset NOW Damage

By Patrick Cavanaugh, Editor

Mating disruption for navel orangeworm works. David Haviland is a UCANR, farm advisor, Kern County. “We all know navel orangeworm is not a simple pest to control and it takes an integrated pest management approach. We know the base of that sanitation—getting rid of all the mummies in the winter to make sure that we reset the clock when navel orangeworm comes back in the spring,” noted Haviland.

“We know that the earlier you harvest, the better you’re going to be. So early and timely harvest is going to help. We know insecticides helped. They’ve been around a while and they’re effective and, certainly, people are using them,” said Haviland. “At the same time, those three things alone don’t always control the pest to the level you need. And that’s where mating disruption can come in as the other leg on the IPM chair.”

Haviland has tested the mating disruption products. Currently, there are three different groups of products registered. There are the aerosol products that releases pheromone throughout at certain intervals throughout the season. The second group, what we call the Meso emitter, that’s a rubber strip that’s hung in the trees that passively releases the pheromone all year and the third group, which is new, is as a sprayable pheromone. It’s one that you put in the tank and you spray it along with an insecticide or fungicide.

“In 2017 trials the big take-home message this that all three of the aerosol products were effective. They all work well, as does the Meso emitter, so all those work about the same,” noted Haviland.

In 2017/2018 Haviland had larger trials that confirmed their previous results. “The earlier trial showed a 40 to 50% reduction in damage, while the later trial on larger acreage showed a 60 to 70% reduction in damage, which was a positive return on investment to the grower,” he said.  In 2018, Haviland conducted the first UC trial on sprayable pheromone products.  They did not work very well.

Almond and Pistachio NOW Sanitation Critical This Winter

Joel Siegel on NOW Sanitation

By Patrick Cavanaugh, Farm News Director

Last year was a bad year for navel orangeworm (NOW) mainly in pistachios, but also in almonds. If left in the trees, infested nuts become a great reservoir for more NOW to inhabit them.

Joel Siegel, NOW research entomologist, USDA Agricultural Research Service
Joel Siegel, research entomologist, USDA Agricultural Research Service

Joel Siegel, a research entomologist for the USDA Agricultural Research Service based in Parlier, stresses the importance of having a good sanitation plan in place to remove those NOW mummy nuts. “When we talk about sanitation, it should be the foundation for everyone’s nut program. That’s something that you control.”

“In almonds, it’s absolutely essential. Where we’ve taken a look at it in the south, every infected mummy per tree is good for 1 percent damage. So going from one mummy to two mummies, your damage on average increases another 1 percent.”

“It’s also important to destroy the mummies on the ground. You figure, for every eight or nine mummies on the ground, that’s good for about a half a percent increase in damage. Get them off the tree and shred the almonds.”

Siegel noted that while pistachio growers can clear mummy nuts off the tree, the industry has not been able to shred the fallen pistachios effectively. The hard, rounded pistachio shells just bounce around in the shredder machine.

almond_mummies
Almond Mummies

“What you can do is shake them off the tree as soon as possible so they’re on the ground where they can start rotting. You get those weeds growing around them. It has been shown that they break down faster in the weeds,” said Siegel.

“Growers disc them in. But if you’re going to disc them in, you have to disc them twice. Again, you’re not destroying the nuts, you are burying them so that NOW cannot lay eggs in the spring,” he said.

The risk of poor sanitation is high. Considerable NOW damage can prevent pistachio and almond growers from earning the premium paid for nuts that are pest-free.

Navel Orangeworm Pressure Imminent

Almond Growers Get Ready to Treat for Navel Orangeworm

Almond and Pistachio growers should be ready to fight back on a particular seasonal pest this year.

Joel Siegel is a research Entomologist with USDA ARS in the Fresno County Office in Parlier. He is an expert on troubling pest for Almonds and Pistachios called NavelOrangeworm. He said growers need to be ready.

“Ok the big thing this year is because of the heat. If the almonds, if the non [ prowlers?] are splitting earlier you better be prepared to be spraying earlier,” said Siegel. “Its really based on nut vulnerability in my opinion, so you have to make your plans now. Get your materials secured so that you’re ready to move.” he added.

Growers need to get ready to protect their crops. Siegel discusses how another important crop, Pistachios need to be protected from the Navel Orangeworm.

“With pistachios, its harder to predict vulnerability, but all of this heat means we have the potential for an additional generation at least. So there could be more pressure. And again there is going to be more of a need to scout, and again make your plans in advance, and make sure you have your materials lined up.

Because of the daytime heat, Siegel said we are ahead of last year, which was a bad year for NOW.

“Well what we are in terms of heat units, is depending where anywhere between four to eleven days ahead where we were last year. And again, from talking to people on the nonpareil seem to be, maybe eight to ten days earlier this year,”

Siegel said just like almonds, being prepared is the most essential.

“If everything is vulnerable earlier you have to be prepared to move earlier than you’re used to doing it. With pistachios, there might be that dragged out cluster development, and again if people are going to have to harvest late, there is going to be more pressure on the back end.” said Siegel.

Siegel was speaking at the recent Southern San Joaquin Valley Almond Symposium in Kerman California.