At local coffee shops, Viveros recalls growers’ verbal chatter on the dream of achieving 2,000-pounds per acre.

Almond research including regional variety plots, pruning, noninfectious bud failure, and post-harvest irrigation brought the dream to fruition. Regional variety plots in 1974, 1986, and 1993 assessed variety performance under commercial conditions.

“We learned Nonpareil variety yields increased when planted in a 1:1 arrangement,” Viveros said. “Bloom overlap was extremely important. We learned that Butte had tremendous yield potential.”

As a result of the regional variety trials, the varieties Solano, Winters, Sonora, and Padre were released.

“I didn’t think Padre would be a highly yielding variety but it was extremely productive.”

Noninfectious bud failure studies assessed Nonpareil and Carmel clones.

“The Nonpareil clone 2-70 had very low bud failure potential,” Viveros said. “Most nurseries today have adopted the Clone 2.”

Over the decades, entomologist Walt Bentley says pest management research has reduced nut losses statewide which translate into higher yields. Improved winter orchard sanitation has significantly reduced navel orangeworm (NOW) losses — 8.8 percent in the late 1970s to 0.68 percent for the 2011 crop.

As California almond acreage edges closer to 1 million acres, Bentley is concerned about increased pest problems. NOW is a significant pest in almonds, walnuts, and almonds. Different nut types are planted closer than ever before. This will make insect control more difficult.

Bentley’s preferred choice to reduce insect infestation and damage is winter sanitation practices.

“We are getting to a point where navel orangeworm control requires an area management approach,” Bentley said. “The most effective control of NOW is winter sanitation. The lack of sanitation is the best threshold for NOW damage.”

Precise timing of insecticidal applications is also important for NOW control. A three-day late treatment can reduce NOW control by 20 percent.

Bentley will retire from UC in June.

In closing the workshop, Viveros asked and answered the almond industry’s 500-pound gorilla question. Is a 5,000-pound per acre goal achievable at a low cost?

“I doubt it,” Viveros said.

“High density plantings may not generate 5,000 pounds per acre. To achieve higher yields, tree density needs to fit the soil and soils should be free of water penetration problems. A well-designed irrigation system is critical while following good irrigation and fertilization practices.”

It is very important to be a good horticulturist, Viveros says.

cblake@farmpress.com