Monday, September 25, 2017

Some Growers Could Fetch Lower Returns for their Almonds This Season

There’s been a lot of chatter circulating on social media, in coffee shops and other gathering spots frequented by almond growers.
Some growers are surprised by crop reports on pest damage.

The talk around town centers on early reports from almond hullers that their crop experienced more pest damage than anticipated.

“They’re getting higher pest damage numbers than they thought. Growers don’t know what’s going on. It’s very puzzling to them,” field scout Jenna Mayfield reports. “It affects the price they get,” Jenna says.

Simply put: Greater pest damage means a lesser quality crop. That means growers will earn less money than expected.

Apparently, pest monitoring didn’t catch the actual number of pests prowling the orchard. They reason is unclear, Jenna says.
A pheromone mating disruption canister placed in a tree.

Of course, there’s plenty of speculation. Some cite the use of pheromone mating disruption devices – called puffers –designed to control male pests, especially the dreaded navel orangeworm (NOW).

Perhaps puffers from neighboring areas skewed the results in the grower’s pest traps. You might call it the almond version of a false positive report (meaning while pest control advisers and growers found fewer NOW eggs in the traps there were really a lot more crop damaging pests out in the orchard).

These puffers have been around for some two decades to control pests in tree crops across California. They are considered labor-saving technology.

The puffers are hung on tree branches and placed around the orchard. The canisters often will spray pheromone doses on a 12- or 24-hour schedule.

Navel orangeworm damage in almonds          (UC IPM photo)
Some studies indicate the puffers alone won’t significantly reduce NOW damage in almonds. They are most effective when combined with soft pesticide treatments. University of California researchers estimate mating disruption systems are used on more than 200,000 acres of almonds and pistachios across the state.

“MD (mating disruption) can work, but needs careful monitoring and large-scale cooperation between neighbors to work well across an entire area,” according to a 2012 article by Franz Niederholzer, a UC Cooperative Extension farm advisor for Colusa, Yuba and Sutter counties.

“Upwind portions of an MD block can have high NOW damage at harvest if neighboring blocks have high pressure. MD is not a stand-alone practice under high pressure.”

This is where the good neighbor policy comes in handy.

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