Tight Shell Means Less Pests

Taylor Hillman Special Reports

Almond Hull crack
One way almond breeding is helping to reduce pests and disease is by looking for a happy medium between a tight shell and an easily cracked nut.

Continuing our series with Burchell Nursery, the Fresno County nursery has many trials underway all of the time. Burchell Nursery product development and plant breeder John Slaughter says there are some distinct qualities the nursery looks for in almonds, and some qualities it wants to prevent. “What we don’t want to see are varieties that are open-sutured or really fluffy, fibrous inner hulls which make a good egg-laying habitat for navel orangeworm, peach twig borer and others,” Slaughter said. “The Spanish varieties, historically, were not sprayed with pesticide to take worm numbers down. They were basically impenetrable by rodents or by insects and were storable, long term, for that reason.”

Slaughter said the nursery’s breeding is looking for a compromise between a tight seal and yet a still manageable shell. “California varieties tend to be a much higher meat-to-shell ratio. We could benefit from some well-sealed, fairly firm shells,” Slaughter said. “We don’t need to go to the extreme, and shouldn’t, that Europe has traditionally done even though they are changing and planting better shelling varieties. You want them to shell well with current machinery. You don’t want to be out there with an anvil and a mallet, but we do want well-sealed nuts to reduce the pressure that insects give us, lower inputs for growers and increase food safety.”