Pest Archives - West Coast Nut

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Pest



Walnut Pest Management: Walnut Husk Fly & Pacific Flatheaded Borer


It seems that growers are always battling pests in order to protect their crops. While we looked into navel orangeworm and codling moth in the first part of this two-part series, this second part shines the light on walnut husk fly and the Pacific flatheaded borer. So just how concerned should a walnut grower be about these pests? They don’t require equal interest, as one is more of a concern than the other. Walnut Husk Fly About the size of a housefly, and far more colorful, the walnut husk fly has one generation per year, in which female flies lay eggs beneath the surface of the walnut husk. The first sign of infestation is a point-sized, stinglike mark on the husk. And while it might initially be an easy miss, the husk will eventually show black marks as the eggs hatch and the maggots feed and destroy it. After feeding,...

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Increasing Evidence of Pacific Flatheaded Borer Attack in Walnut Orchards in California


Background and Pest Status Flatheaded borer is a larval stage of one specialized group of beetles (Insect family-Buprestidae), which are glossy iridescent colors. The name ‘flatheaded’ comes from the enlarged and flattened shape just behind the head of the larval stage (Fig. 1) of the beetle (Fig. 2), and the flatheaded borer species that has become a major issue in walnuts is Pacific flatheaded borer (PFB), Chrysobothris mali, which is known to present in the western states such as Washington, Utah, Oregon, California. A similar type of borer species causing serious damage in various nurseries and other fruit and trees in the eastern part of the United States is called Appletree flatheaded borer, Chrysobothris femorata. Although Pacific flatheaded borer has been an occasional pest of young fruit and nut crops in the past, in recent two years, this borer has become a...

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Walnut Pest Management: Navel Orangeworm and Codling Moth


There are a few pests that have reached what seems like celebrity status in the tree nut industry, with codling moth and navel orangeworm being household names for walnut growers. With research is continuing on how to best eliminate these pests, there are still methods and products that can help with the complications of infestation. Navel orangeworm and codling moth are featured here in this first part of a two-part series focusing on pests in walnut orchards. Navel Orangeworm Navel orangeworm has garnered a lot of attention, as growers and industry personnel continue to battle this pest. When mummy nuts are left on trees, the navel orangeworm identifies these as ideal places to lay eggs. Those eggs—which are a solid white when they are first laid, then turn pink, then reddish orange and overwinter as larvae. This moth starts emerging in April, and peaks in late-April to mid-May. The cycle...

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Don’t Forget Winter Sanitation


First flight numbers of navel orangeworm (NOW) in the Sacramento Valley overall looked low to moderate in pheromone traps, but there are some exceptions to that, according to Emily Symmes, UC Cooperative Extension Area IPM advisor, Sacramento Valley. The more severe winter could have kept first flight numbers down, Symmes continued, but also there was a more prolonged spring flight due to relatively cooler temperatures and numerous rain events, which may have appeared as lower overall abundance in NOW traps during the early flights. “I don’t necessarily think this is a low pressure year from an overall perspective, especially now that we are seeing significant numbers in the third flight” Symmes said. Third and fourth flights, if a fourth flight arrives, are always larger as a result of population build-up, and heat units increasing into the summer reduce the generation time, Symmes said. Trapping  Many growers and pest control...

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LFB in Control for Almonds and Pistachios


When you see adult leaffooted bugs (LFB) in your almond or pistachio orchards, it is time to take action. There is no established threshold for economic damage caused by this piercing-sucking pest, said Kris Tollerup, UC Cooperative Extension area Integrated Pest Management advisor. Traps and lures for LFB are still being evaluated. Visual observation of LFB in an orchard should prompt treatment, advisors said. LFB This large insect pest is a native of California, and has been found in the San Joaquin Valley from Butte to Kern counties. While LFB may be found in most valley locations, there are specific environmental conditions that allow for populations to build. Those conditions include riparian areas, protected overwintering sites and host plants. Almond and pistachio orchards adjacent to those sites can become infested and are vulnerable to crop loss or damage from LFB. Tollerup said he has seen a 50 percent almond crop...

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