With almond harvest only 4-6 weeks away, agronomists at the Hickman, CA, Grow More^TM Experience site are preparing growers with late-season management tips. According to agronomist Don Lewis, at this point in the season, yield potential is already established. Where growers need to focus now is on nut quality.

What stands in the way of strong marketability? Insects. Some of the most common late-season insects almond growers face are navel orangeworm (NOW), spider mites and plant bugs. These and many other insects reproduce rapidly during hot California summers, which increases populations exponentially.

• Last season was a particularly hard year for NOW pressure, and growers may find themselves in the same situation in 2018. During the upcoming hull cracking stage, females lay their eggs, and 3-5 days later, the eggs hatch and burrow into the nut. Soft shell varieties are most vulnerable to NOW damage.

Navel orangeworm spotted in almond mummies in Hickman.

• Female spider mites lay their eggs on almond tree leaves and can produce up to 8 to 10 generations a season. Mites attack leaves, and outcomes can be felt for years after initial damage. Some spider mite webs have already been spotted on untreated trees in Hickman.
• Leaffooted plant bug burrows into the side of almond hulls with their needle-like mouths to feed on young nuts. The resulting damage appears as gummosis as the season progresses.

Plant bug damage (gummosis) spotted in untreated trees in Hickman.

At the Hickman site, agronomists are testing an insecticide program to help growers combat insect issues. Besiege® insecticide and Minecto® Pro insecticide in a season-long management program deliver effective control of a variety of common California insects. Besiege provides broad-spectrum lepidopteran control with excellent knockdown and long-lasting residual. Minecto Pro controls a wide range of lepidopteran pests plus mites with long lasting residual control. Compared to untreated and competitor-treated trees, this program approach is demonstrating outstanding control of these damaging pests.

For more information about these insecticide trials in Hickman, contact your Syngenta representative.

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