California Ag Network

Category: Pest/Disease Management

  • A Reminder That It Only Takes One Person To Spread Invasive Pests

    Washington, D. C., (April 12, 2018) – Each year, harmful invasive plant pests and diseases cost the United States about $40 billion in crop losses, damage to forests and vulnerable ecosystems, and expensive eradication and control efforts. It only takes one person who moves one piece of infested firewood, one infected plant, or one piece of infested fruit to spread these invasive pests to a new area. That’s why USDA’s Animal and Plant Health Inspection Service (APHIS) has designated April as Invasive Plant Pest and Disease Awareness Month. Spring is the perfect time to remind everyone of the simple steps they can take to prevent the spread of harmful invasive plant pests.

    The USDA believes that Huanglongbing (HLB, or citrus greening) was spread from Florida to California by one person who likely mailed an infected plant to that State. HLB was first detected in Florida in 2005 and has since spread rapidly. A concerted effort by USDA, states (including California), and the citrus industry is underway to find new strategies in the fight against HLB.

    The good news is that individuals can also stop the spread of invasive pests by looking for and reporting suspicious insects or signs of damage (Report a pest in California). For example, USDA detected Asian longhorned beetle in Boston in 2010 when a single groundskeeper with a keen eye noticed and reported an unusual dime-sized hole in a tree. That one call provided early warning to jumpstart an eradication effort that quickly eliminated this destructive pest from that city.

    Here’s what you can do to help keep invasive pests from spreading as spring gets underway and all year round:

    • Spring is a busy time for buying plants. Buy yours from reputable nurseries or online businesses. Ask if they comply with federal and state quarantine restrictions to ensure their plants are pest-free.
    • Planning to travel? Whether it’s between states or to another country, check with your local USDA office before you bring back fruits, vegetables or plants so you know what’s allowed. And when returning from abroad, always declare all agricultural items to U.S. Customs and Border Protection so they can make sure items are free of harmful pests or diseases.
    • When enjoying the great outdoors, don’t move untreated firewood. Instead, buy or responsibly gather firewood near the place you’ll burn it. Or, take certified, heat-treated firewood on your trip with you.
    • If you live in an area under state or federal quarantine for an invasive pest, don’t move produce or plants off your property. Call your local USDA office to find out how to safely dispose of yard debris like trees and branches. Also, allow authorized agricultural workers access to your property for pest or disease surveys.
    • Make sure to clean outdoor items before moving them. Wash dirt from outdoor gear and tires before traveling long distances to or from fishing, hunting or camping trips. If relocating to a new home, clean lawn furniture and other outdoor items before placing them in a moving van or storage pod.

     

    To learn more, visit www.HungryPests.com or join the conversation on Facebook or Twitter. The website includes photos and descriptions of 19 invasive pests that can be moved easily by people, an online federal quarantine tracker by state, and phone numbers for reporting signs of invasive pests.

  • Considerations for Powdery Mildew Management in the Vineyard this Season

    Special Thanks to This Video’s Sponsor!

    Powdery mildew is an early season disease and growers should have a strategy in place as to how to manage it. Viticulture Farm Advisor Rhonda Smith talked about this at the recent Sonoma Grape Expo. Watch this interview with Rhonda as she offers some considerations for growers moving into the 2018 growing season.

  • What’s That in Your Cornmeal?

    Davis, Calif., (April 3, 2018) – You’re thinking about making Grandma’s Southern Cornbread.

    You head for your pantry. You remember that six months ago you purchased a bag of cornmeal from a local supermarket and that you immediately emptied the contents into a glass jar with a tight-fitting lid.

    You open the airtight jar and notice something strange. It’s moving. Moving? Moving? Yes! It’s crawling with a transparent carpet of dozens of nearly microscopic critters.

    What? First, what are they? If you’re like me, you grab your camera–in this case, a Canon EOS 7D with an MPE-65mm lens that can magnify an insect five times its life size–and click the shutter.

    You post the photo on BugGuide.Net and request an identification.

    The entomologists all agree: They’re booklice, Liposcelis bostrychophila.

    • Class Insecta (Insects)
    • Order Psocodea (Barklice, Booklice, and Parasitic Lice)
    • Suborder Troctomorpha
    • Family Liposcelididae (Booklice)
    • Genus Liposcelis
    • Species bostrychophila(Booklouse)

    These Liposcelis bostrychophila, or “psocids” (pronounced “so kids”), are common pests in stored grains. They’re usually unseen because they’re about a millimeter long–about the size of a speck of dust–and are transparent to light brown in color. They’re also wingless, but can they ever crawl!

    Fact is, their name, “lice,” is misleading. These tiny insects are not lice; they are not parasitic. And they’re everywhere. They feed on flour, cereals, grits, molds, fungi, papers, books, pollen, dead insects and the like. In fact, you’ve probably unknowingly eaten them–or parts of them–in your pancakes, your oatmeal or maybe even your chocolate birthday cake.

    Entomologist Jeff Smith, who curates the butterfly-moth collection at the Bohart Museum of Entomology at UC Davis, took one look at the photo and commented:  “They’re pretty thick in there!”

    “Booklice can be scavengers and often feed on the bits of mold or fungi that grow on damp materials,” Smith explained. “Very old, neglected food stuffs are also subject to them, and the key to prevention is to use food materials reasonably quickly and not store them for years, store them in a nice dry location and in airtight containers.”

    “They very well could have been in the food already when you bought it, but they’re so common that you probably have some roaming around in the house all the time, just looking for something good to eat. They’ll feed on dead bugs in window sills, stale pet foods, etc.”

    If you’re worried about what’s in your cornmeal, flour, oats, biscuit mix, cake mix and other stored foods, you can pop the contents in your oven at about 120° for a half hour, and then transfer them to an airtight container, Smith says.  “Your food should be okay–albeit perhaps containing a few dead booklice. We had them in an old bag (paper) of rice one time, and in several packages of cornmeal mix that were forgotten in the back of our cupboard.”

    A UC Davis colleague said he’s seen them crawling in his flour, but his wife made pancakes from them anyway. No issues. No problem. “Just protein!” he chortled.

    And from another colleague: “I once had an entire case of instant grits. The grits were completely factory-sealed in unopened plastic bags. I opened the bags and the grits were poured into hot water, but they would not sink and mix with the water.  Instead the grit floated on the top of the water. I opened a second bag and looked at the grits under my stereo microscope. Each and every grain of grit had two or three little six-legged creatures standing on each grit. These creatures were 100 percent transparent, the only color was in their bodies which was the same color as the grits they were eating. I opened every 100 percent factory-sealed bag, and every bag was contaminated in this matter.”

    “There is nothing new about insect contamination of grain products,” she added. “Another personal experience was a biscuit mix. For no particular reason, I sifted the biscuit mix while making the batch of biscuits. After sifting several cups of biscuit mix, in the sifter screen there were 4 worm-like creatures about the diameter of a standard pencil and about an inch long. These worms were 100 percent transparent, each filled with the white biscuit mix. “Consider we all eat insects, spiders, and urine and feces of all sorts of animals.”

    We live in world where we all eat bugs, whether we know it or not. Sometimes we may not want to know!

    Statistics indicate that the average American unknowingly eats one to two pounds of insects a year.  But the U.S. Food and Drug Administration “has very specific tolerances for the amount of residue in food stuffs,” said Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis.

    Want to know what the action level is? Check out this FDA document.

    And the next time, you’re yearning to make Grandma’s Southern Cornbread, you might want to check for bugs first. Or maybe not. You might not want to know!

  • Research Reveals a New Direction for Halting the Citrus Greening Epidemic

    Ithaca, New York, (April 2, 2018) – New clues to how the bacteria associated with citrus greening infect the only insect that carries them could lead to a way to block the microbes’ spread from tree to tree, according to a study in Infection and Immunity by Agricultural Research Service (ARS) and Boyce Thompson Institute (BTI) scientists.

    Citrus greening, also known as “huanglongbing,” is a serious disease dramatically affecting citrus production across the world. Trees with this disease all die after only a few years. Citrus greening has been detected in every citrus-producing county in Florida, throughout the southern citrus growing states and in isolated spots in southern California. There is no effective prevention or cure.

    The disease is associated with the bacterium Candidatus Liberibacter asiaticus, CLas for short, which is spread from tree to tree only by a tiny insect vector—the Asian citrus psyllid. If CLas cannot infect the psyllid, its ability to spread citrus greening is halted.

    With the long-term goal of disrupting this CLas-Asian citrus psyllid interaction, research molecular biologist and BTI professor Michelle Heck, with the ARS Emerging Pests and Pathogens Research Laboratory, and BTI researcher Marina Mann focused on an important point: not all psyllids spread CLas equally well.

    To be spread by the Asian citrus psyllid (ACP) effectively, the bacteria must pass through the cells lining the insect’s gut and multiply. Scientists in Heck’s lab had previously shown that the gut cells of adult ACP show severe stress responses when infected by CLas. The cell nuclei become fragmented, and some cells react to the point of dying, allowing the bacteria to move out of the psyllid and into the tree.

    Now, the researchers have found that, unlike adult psyllids, young psyllid nymphs appear to be resistant to the effects of exposure to CLas, and their nuclei rarely reach the same level of disruption. This means CLas cannot enter psyllid gut cells to multiply.

    The next step will be to identify the mechanism for this resistance in the nymphs so that it might be manipulated to also halt the spread of CLas by the adults. An important clue lies in how psyllid nymphs interact with symbiotic bacteria in their gut, especially Wolbachia pipientis.

    Many insects are hosts for Wolbachia and often depend on these bacteria for important benefits—much like how human health depends on gut bacteria. In their study, Mann and Heck showed that in psyllid nymphs, Wolbachia and CLas are commonly found within the same cells.

    The authors hypothesize that, in accommodating the beneficial bacteria, the nymphs also let in more CLas. This is supported by their finding that CLas levels in psyllid nymphs are strongly correlated with Wolbachia levels. Though this link remains to be tested directly, understanding its mechanism could yield an important target for disrupting CLas-psyllid interaction.

    “CLas exploits the way nymph and adult psyllids differ in their guts to gain entry into its insect vector,” Heck said. “We may be able to use this new foothold in our understanding to develop ways to block transmission by insects in the citrus grove.”

    If this works, “citrus growers will be in a much better situation in terms of disease control and saving the U.S. citrus industry,” said Dan Dreyer, Chairman of the California Citrus Research Board, which funds this and other research aimed at developing a management strategy for citrus greening.

    “There are still many unanswered questions about CLas, how it is acquired and transmitted via the Asian citrus psyllid, and how it causes the disease,” continued Dreyer. “The more we learn about CLas and its vector, the closer we will get to moving citrus production past the threat of citrus greening.”

    The Agricultural Research Service is the U.S. Department of Agriculture’s chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $20 of economic impact.

  • New Early ‘Gumdrop’ Pistachio Variety is Finally Here

    Special Thanks to This Video’s Sponsor

    What if you could have a pistachio variety that you could harvest earlier to reduce the chances of having Navel Orangeworm damage and concern for Aflatoxin levels?  Well, the new early ‘Gumdrop’ pistachio is here.  At the Annual American Pistachio Growers Conference, Bob Klein from the Pistachio Research Board talked about this new variety that is now available to growers on a small scale.  Read more about it in Pacific Nut Producer Magazine.

    Enjoy our Ag video news?  Be sure to let our sponsor Duarte Nursery know & thank them for their industry support!

  • CDFA to Receive $14.8 million in Farm Bill Funding for Pest Projects

    Sacramento, Calif., (March 27, 2018) – The U.S. Department of Agriculture (USDA) is allocating $14.8 million to California from Section 10007 of the 2014 Farm Bill as part of its effort to strengthen the nation’s infrastructure for pest detection and surveillance, identification, and threat mitigation, and to safeguard the nursery production system. Overall, USDA is providing nearly $70 million in funding this year that will support 494 projects across the country.

    “We are pleased to partner with California to provide critical Farm Bill funds that will put innovative ideas into action and help us overcome our shared invasive pest and disease challenges,” said USDA Under Secretary Greg Ibach. “California is a critical partner in protecting U.S. agriculture. These projects will enable California to protect its own resources, and, in doing so, contribute to USDA’s mission of keeping our nation’s agriculture economy healthy and strong.”

    These funds will support projects covering a range of plant health and pest mitigation activities, including the following:

    • $4.3 million to survey for harmful exotic fruit fly populations in the State;
    • $3.5 million to support the activities of California’s agricultural detector dog teamssearching for harmful, exotic plant pests in packages at mail and express parcel delivery facilities;
    • $1.8 million to support National Clean Plant Network foundation plant stocks for citrus, grapes, fruit trees, sweet potato, and roses;
    • $1.7 million to support California’s Emergency Plant Health Response Teams for responding to, delimiting the infestation area, and managing outbreaks of exotic plant pests;
    • $1.3 million for survey activities for plant pests such as Asian defoliator moths, Khapra beetle, and pests harmful to citrus, stone fruit, and palm commodities;
    • $1.1 million to develop or enhance plant pest and disease diagnostic and identification technologies for exotic fruit flies, cyst forming nematodes, downy mildew, and others;
    • $740,000 to develop best management practices for pest and disease mitigation at ornamental nurseries;
    • $260,000 to identify and use predatory insects as biological control tools for the insect pests Bagrada bug and shot hole borer;
    • $80,000 to support improvement of Varroa mite resistant commercial honey bee stocks; and
    • $9,000 for the development of molecular tools for the detection of gall forming nematodes in the family Anguinidae.

    USDA has provided approximately $263 million in Section 10007 funds to support more than 2,200 projects since the 2014 Farm Bill was enacted. Collectively, these projects continue to bolster our country’s safeguarding system while allowing USDA and its partners to quickly detect and rapidly respond to invasive pests and diseases. You can view the FY 2018 spending plans on the USDA Animal and Plant Health Inspection Service (APHIS) Web site at www.aphis.usda.gov/farmbill.

    APHIS created the Hungry Pests public outreach program to empower Americans with the knowledge they need to leave these “hungry pests” behind. Visit www.aphis.usda.gov/pestsdiseases/hungrypests to learn more about invasive plant pests and diseases impacting your area and how you can help.

  • Roof Rats Unnerve Farm Workers, Damage Orchard Crops

    Davis, Calif., (March 22, 2018) – Monitor for rodent activity and use bait stations before the growing season to prevent problems, UC ANR scientists recommend.

    Roof rats are running rampant in California orchards this year, according to UC Agriculture and Natural Resources scientists.

    “In pistachio and other nut orchards, roof rats are burrowing and nesting in the ground where they’re chewing on irrigation lines, causing extensive damage,” said Rachael Long, UC Cooperative Extension advisor. “They are also nesting in citrus trees, feeding on the fruit and terrifying field workers when they jump out as people are picking fruit. The chewing pests are also girdling citrus limbs, causing branch dieback.”

    The wet winter of 2017 led to lots of weed seeds for rats to eat. “Last season, rats were also nibbling on pomegranates, avocados, and other fruit and nut crops, rendering them unmarketable,” Long said.

    Holes in the ground around the base of pistachio trees throughout a Yolo County orchard puzzled the grower.

    “We looked for ground squirrels, but never saw any,” Long said. “We set up game cameras, but only got birds and rabbits. We put rodent bait in the holes, but the digging didn’t stop.”

    Long, the pest detective, cracked the case by consulting Niamh Quinn, UC Cooperative Extension human-wildlife interactions advisor based in Irvine. “She informed us that the damage we were seeing was from roof rats.”

    Burrowing roof rats sounds like an oxymoron. While roof rats generally don’t burrow in urban environments, their country cousins have been known to burrow.

    “It’s not true that they don’t burrow,” Quinn said. “When I worked as staff research associate for Roger Baldwin, UC Cooperative Extension wildlife specialist, that is mostly what we studied, burrowing roof rats in orchards.”

    Roof rats are nocturnal animals that climb trees and burrow underground.

    Control measures – Baldwin said, “It seems to be a good year for rats in a number of different areas and crops throughout the state. I’ve received more questions and comments about rats this year than perhaps the last 10 years combined. As for bait application, putting bait down burrow systems for rats doesn’t usually work too well, so I’m not surprised that approach didn’t work. Growers will likely have better luck with bait stations in the trees.”

    Because the rats climb, Baldwin suggests attaching bait stations to tree branches.

    “In addition, elevating the bait stations will eliminate access to bait for many protected mammal species, such as kangaroo rats,” Long said. “The bait diphacinone grain can be purchased from some ag commissioners’ offices. This is what Roger Baldwin said they tested and it worked.”

    As for the bait stations, they should be designed so that there isn’t any spillage for nontarget animals to eat, Long said.

    When roof rat outbreaks occur, rodenticides are often needed to prevent crop damage. However, timing is critical as diphacinone use is highly restrictive and not allowed during the growing season, which is beginning as the weather warms.

    “Check the product label for application instructions,” Long reminds growers. “It’s the law.”

    Because roof rats climb, UC Cooperative Extension wildlife specialist Rager Baldwin recommends attaching bait stations to tree branches.

    Identifying the pest – One way for growers to identify whether they have roof rats is by the size of the burrows. The nocturnal pests are active above ground in trees and below ground.

    “Roof rats can forage away from their nest, so you won’t likely find signs of their activity, such as rat droppings outside their burrow, to help identify them,” Long said.

    Ground squirrels are active during the day, so they are more likely to be seen, dig holes about 4 inches in diameter and forage above ground near their burrows. Vole and mouse holes are 1- to 2-inches in diameter. Roof rat holes are typically 3 to 4 inches in diameter and might have nut shells in front of them, for example pistachio or almond shells. Rabbits will feed on seedling crops, but do not dig burrows.

    Roof rats are prolific breeders that reproduce year-round, according to Baldwin. Females typically have three to five litters per year with five to eight young, enabling their populations to rapidly increase. The omnivores feed on a wide variety of plant and animal materials, allowing them to adapt to any environment, including urban and agricultural lands.

     

    “Rats are sneaky and hard to spot,” Long said. “If you see damage, including digging in the soil but no wildlife, suspect rats.”

    For more information on controlling roof rats, download Quinn and Baldwin’s free UC ANR publication 8513, Managing Roof Rats and Deer Mice in Nut and Fruit Orchards at http://anrcatalog.ucanr.edu/Details.aspx?itemNo=8513.

    For more information about ground squirrels, download the free UC IPM Best Management Guidelines http://www.groundsquirrelbmp.com or UC IPM Pest Note http://ipm.ucanr.edu/PMG/PESTNOTES/pn7438.html.

    Roof Rats are causing damage in nut and tree fruit orchards.
    Roof rat holes are typically 3 to 4 inches in diameter.
    Ground squirrels are active during the day and their burrows are 4 inches or more in diameter.

  • Successes & Concerns for the American Pistachio Industry

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    Pistachio growers just enjoyed gathering for the annual American Pistachio Growers Conference last week. Watch this conference wrap-up interview with APG Executive Director Richard Matoian as he shares the current State of the Pistachio Industry, both the successes, and some concerns for the industry moving forward. Read more about it in the coming issue of Pacific Nut Producer Magazine.

    Enjoy our Ag video news?  Be sure to let our sponsor Duarte Nursery know & thank them for their industry support!

  • South America Palm Weevil is Killing Palm Trees in Southern California

    San Diego, Calif., (March 13, 2018) – South American palm weevils that have made their way north from Mexico are having a destructive impact on palm trees in the San Diego region, reported Abbie Alford on CBS News 8 TV in San Diego.

    UC Cooperative Extension specialist Mark Hoddle, the director of the Center for Invasive Species Research at UC Riverside, toured the reporter through the hard-hit Sweetwater Reserve in Bonita, where 10 percent of the palms die every three months.

    “We are going to see hundreds, thousands of Canary Island Date Palms die over the next couple of years,” he said.

    A Canary Island Palm in San Ysidro killed by South American palm weevils.

    The weevils use their protruding noses to drill holes in the palm, where females lay their eggs.

    San Diego County Agriculture, Weights and Measurements said it plans to remove 50 infested Canary Island Palms from the Sweetwater Regional Park and is educating arborists about the invasive pest.

    A spokesperson for the City of San Diego said it is working with UC Cooperative Extension.

     

  • Sterile Insect Technology for Navel Orangeworm Control Field Trials Begin

    Special Thanks to This Video’s Sponsor

    Navel Orangeworm (NOW) continues to be a growing pest for almond, pistachio & walnut growers all over California.  Last year was an especially difficult year, as there were growers that experienced significant crop loss who have historically not had issues with the pest before.  Bob Klein with the Pistachio Research Board recently reported on a field trial they will be conducting utilizing sterile insect technology to minimize NOW populations in the orchard.  Watch this video and read more about it in Pacific Nut Producer Magazine.

    Enjoy our Ag video news?  Be sure to let our sponsor Duarte Nursery know and thank them for their industry support!