Morse spent the balance of his time discussing chemical sprays for psyllid control, and the importance of using different modes of action to reduce possible pest resistance.

“We can’t control the psyllid forever with chemicals,” Morse said. “I think we can do a good job with insecticides for the next five to 10 years until the industry develops long-term solutions.”

The winter months are the prime time for psyllid sprays.

“Use the winter spray treatment as one of your big hammers to knock down psyllid numbers,” Morse said. “Based on experience from Florida, if you don’t control the psyllid effectively during the winter, you may never catch up during the summer.”

Insecticides for psyllid control include broad spectrum and more selective materials. The top broad spectrum insecticide chemistries for winter use against adult psyllids are pyrethroids, organophosphates, and carbamates.

Morse offers suggestions to help reduce pest resistance to insecticides:

  • Minimize pesticide use - treat only as needed.
  • Coordinate area wide treatments with nearby growers.
  • Rotate classes of pesticide chemistry - more persistent pesticides have a greater potential for resistance.
  • Know which class of chemistry each pesticide represents.
  • For pests other than the psyllid, consider a less effective chemical if it represents a different class of chemistry.

He encouraged citrus growers to participate in area wide sprays with neighboring growers with all sprays applied within a two-week period.

“It only takes a few people who don’t spray to ruin the entire program,” Morse said.

The entomologist says neonicotinoids are best used prior to the fall flush (growth) period, not the spring flush.

An imidacloprid soil treatment is very effective. One-half pound active ingredient is allowed annually. Morse says apply the full label rate in one treatment.

Commercial sponsors of Fall Desert Crops Workshop included: Platinum Sponsors – BASF and Bayer CropScience; Gold Sponsors – Dow AgroSciences, DuPont, and Westbridge Agricultural Products; Silver Sponsors – FMC, Ocean Agro, and Valent; and Bronze Sponsors – Syngenta and Oro Agri.

California citrus, a $2 billion industry annually, is mostly grown for the fresh market (80 percent). Oranges comprise about two-thirds of the statewide crop – Navels and Valencias (75 percent and 25 percent respectively). A third of the crop is exported. About 90 percent of the nation’s lemon crop is grown in California.

The Arizona citrus industry produces mainly lemons; a combined $60 million-plus industry. Arizona has the psyllid but no confirmation of HLB.