Even with a pyrethroid treatment last month to turn back a leaffooted plant bug threat on a 400-acre almond orchard in southern Kern County, PCA Andrea Gjerde continues to keep an eye out for any possible outbreaks of the insect.
Prior to spraying, the insect had caused small, newly-forming nutlets to drop. And while she hasn’t seen any damage or gummy nuts since then, she remains wary. The orchard includes 14- to 17-year old drip-irrigated Nonpareil and Butte varieties.
“They border an urban area where the leaffooted plant bug migrated from conifers in backyards to almonds when the weather warmed up,’ says Gjerde, who’s with Entomological Services, Inc., Visalia, Calif.
“Normally, a spring spray will control the insect. But, some growers and PCAs report that they’ve had to treat for it in Kern County, even after shell hardening. So, we’ll be watching for it through the season.”
At mid-May, she applied the spring spray for navel orangeworm. She’s also keeping her eyes peeled for spider mites, and she’s been putting out bait for fire ants.
“In the second week of May, one of our navel orangeworm traps was attacked by fire ants,” she says. “The ants had to go up the trunk of the tree to get to the trap, so clearly, that ranch has a fire ant problem.”
Gjerde plans to recommend broadcasting ant bait throughout the orchard in early June to attract ants to the bait as they forage. The bait has an insect growth regulator effect on the colony and some direct toxic effects on foraging worker ants, she says. Foraging ants take the bait back to the nest and feed developing larvae and the queen. The larvae fail to mature and queens die or become sterilized.
The unusually cool, wet weather, including the third week of May, had delayed insect development in general this spring, Gjerde says. But, with 80-degree temperatures the fourth week of the May, she expected insect growth and activity to begin catching up.
Meanwhile, nut development is showing normal progress. “The trees are looking very healthy, and I think they have a nice crop on them,” she says. “The other IPM people I’ve met with recently are talking about a big crop this year. In fact, I’ve heard of some Monterey orchards that are shedding nuts because the crop is so big.”