Little Time to Rest as Almond Growers Prepare for Hullsplit

Despite the sunrise-to-sundown work schedule, the Fourth of July holiday brought a welcome, but brief respite for growers – a time for barbecues, fireworks and get-togethers with friends and family. But there’s no rest for the weary.

Almonds are heading into hullsplit around the valley.

Almond growers, for instance, are keeping an anxious eye on their crop as it heads toward the backstretch to harvest time. Field scout Jenna Horrine reports growers are figuring out the timing for hullsplit sprays to protect against crop-damaging pests. 

UC IPM and extension advisors recommend growers follow an IPM and resistance-management approach to managing navel orangeworm (NOW) and spider mites. Most growers will spray for NOW at hullsplit and many make another application two or three weeks later.

Often, there are enough natural enemies in the orchard to control mites during the late season. If treatment is necessary, combining miticides with the hullsplit spray for NOW can save money by avoiding a separation application.

Monitor for pests before treatment.

Here’s what UC IPM says about hullsplit treatment: time the spray to the beginning of hullsplit “if eggs are being laid on egg traps; otherwise time it to an increase in egg-laying on traps or the predicted initiation of egg-laying following hullsplit. Hullsplit is determined to begin when sound fruit in the tops of the trees begin to split. At this time, the nuts at eye level will be less mature than those at the top and have only a deep furrow in the hulls. Nuts in the top southwest quadrant of the tree split first. Blank nuts (usually 3 to 5 percent) will split one to two weeks ahead of sound nuts. Use a long-extension pole pruner to cut small branches from the top portion of five or six trees in the orchard to check whether hullsplit nuts are blank or sound.”

Check traps for pest eggs.

“Check for eggs on egg traps. If hullsplit has begun, but eggs are not being laid, wait until egg-laying starts. After hullsplit begins, egg-laying on traps may decrease due to competition of the traps with the new crop nuts. Therefore, if you do not see eggs on traps, use degree-days and apply a treatment at 1,200 degree-days from spring biofix,” UC IPM says

Weekly monitoring of spider mites and predators should determine if miticide applications are needed.“When monitoring for spider mites, PCAs should also be looking for six-spotted thrips, predatory mites, spider mite destroyers and minute pirate bugs,” says David Haviland, an entomologist and almond expert with UC Cooperative Extension in Kern County.

UC guidelines call for treating for mites if half of the leaves sampled have mites. If there are no predators, then treatment should be made if 25 percent of the leaves are infested.

Jenna again stresses this is the time to closely monitor their orchards to keep on top of the pests and avoid a sudden population explosion just before harvest. Jenna says one orchard is already seeing the first signs of the hulls splitting. Other growers are expecting the almond hulls to start splitting soon.

Cotton plants are starting to experience bloom in the field.

Before we know, harvest time will be here. Jenna notes the earliest tree shaking last year came on July 25.Shaking time is around the corner.Meanwhile, field scout Carlos Silva says cotton growers are wrapping up the second irrigation of the growing season. The plants are at the colorfully flowering stage, lighting up fields with various shades of pink, white and yellow. So far, there aren’t any major issues with pests.
In alfalfa, growers are pretty much finished with another cutting and leaving strips of uncut alfalfa to keep lygus from migrating to nearby cotton fields. “There are a lot of beneficial insects in the alfalfa fields,” Carlos says.
  

Field Day Alert: Growers are invited to attend a Summer Alfalfa Field Day on Wednesday, July 15 from 10 a.m. to 12:30 p.m. at Bowles Farming at the intersection of Hereford Road and Bisignani Road in Los Banos. The speakers are UC IPM advisor Dr. Pete Goodell on insect management; UCCE Davis alfalfa extension specialist Dr. Dan Putman on current issues, including weeds, water quality and availability and summer retirement of alfalfa fields; Merced County Deputy Agricultural Commissioner Sean Runyon on an update of chlorpyrifos regulations; and Cannon Michael of Bowles Farming. Continuing education credits should be available. For more information contact Marcia Gibbs at (530) 370-5325 or marcia@sustainablecotton.org