California Ag Network

Category: Pest/Disease Management

  • First Genome of Spotted Lanternfly Built from a Single Insect

    Agricultural Research Service (ARS) scientists, in cooperation with Pacific Biosciences and Penn State University, have published the first genome of the invasive Spotted Lanternfly (SLF) in the journal Gigascience and they did it from a single caught-in-the-wild specimen.

    Not only is it the first published genome for this pest, but no closely related species has had its genome sequenced, making the data even more important, according to entomologist Scott M. Geib with the ARS Daniel K Inouye U.S. Pacific Basin Agricultural Research Center.

    SLF, a native of China, Bangladesh and Vietnam, was first found in Pennsylvania in 2014 and has now spread to Virginia, Maryland and New York. This invasive pest has a taste for almonds, apples, apricots, grapes, peaches, blueberries and hops as well as hardwoods such as oak, walnut, and poplar. Various estimates put the potential economic damage in the billions of dollars, if the SLF becomes widely established in the United States.

    “Having the genome for this pest opens the door to a better understanding of its biology and behavior, and makes coming up with potential control methods much more likely to happen, such as developing a lure for a trap through understanding the insect’s olfactory genes, or exploring avenues such as gene editing or RNAi,” said Geib.

    While having the SLF genome is critical for the management and control of this invasive pest, the approach taken to obtain the genetic data is an achievement of remarkable note as well. For the first time, all of the DNA required to generate a whole genome sequence was taken from a single insect picked from a tree in the wild in Reading, Pennsylvania, across the street from the Reading Pagoda on Mt. Penn.

    One hurdle for deciphering this species’ genome is its relatively large genome size, at about 2.2 billion base pairs. Typically, with previous sequencing systems, many sequencing runs would have been needed to do the complete job, with each run using up the available DNA for the organism being sequenced.

    So often to have sufficient DNA for a complete genome sequence, many organisms would need to be pooled, introducing more opportunities for errors to be generated. To avoid such potential for errors, the subjects—especially insects—often have to be raised in colonies and inbred.

    “In cooperation with Pacific Biosciences and using their new sequencing platform—the PacBio Sequel II—that produces 10 times the data from a single sequencing run, we were able to generate sufficient coverage from just a single specimen. This allows for a very fast turn-around of data and assemblies as well as lowers cost, in this case under $2,000 in consumable supplies, not including the purchase price of the sequencing instrument of course,” explained Geib.

    For genome completeness, and since there aren’t many related genomes to compare that of the SLF to, the team checked a set of “core genes” that should be present exactly one time in all insects and verified how many of these were found in this genome project. In this case, they found about 97 percent of these single copy core genes, with a very low rate of duplication.

    “Sequencing such a large insect genome quickly and showing there is no need to pull the insect into a colony raises the feasibility that we can complete the Ag100Pest Project,” Geib said. The ARS Ag100Pest initiative is focused on deciphering the genomes of 100 insect species that are most destructive to crops and livestock and that are projected to have profound bioeconomic impacts to agriculture and the environment. “Now, with this system, doing 100 or even 1,000 genomes is not unrealistic,” he added.

    The ability to get a complete genome from a small amount of DNA also makes it practical to consider sequencing the genomes of physically tiny insects without having to catch or raise a large number of any one species. That expands the list of insects that may be genetically sequenced.

    By Kim Kaplan, USDA-ARS

    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.

  • Black Soldier Fly to Support Almond Industry

    With a growing almond industry and an increasing supply of coproducts, such as hulls and shells, researchers are searching for new and resourceful ways of utilizing the extra material as an asset.  Breaking these coproducts down to a form that may be utilized back in the soil or as a feed supplement has been a challenge in the past; but this may all change with the introduction of a new helpful fly on the block.  Watch this brief interview with Eric Tilton from Hermetia Pro Inc. regarding this Black Soldier Fly, and read more about it in Pacific Nut Producer Magazine.

     

    Please thank our sponsor Duarte Nursery for their industry support by visiting them at their booth at the following November Events: Tree & Vine Expo, the Grape, Nut & Tree Fruit Expo & Blue Diamond Growers Annual Membership Meeting.

  • Be Sure to Manage these Insect pests in Young Pistachio Orchards

    Growers likely have heard a lot about the damage leaf footed bugs and navel orange worm can cause to their pistachio crop, but what about integrated pest management practices in the early nonbearing years of an orchard?  When there’s no crop, growers may overlook the impact that some insect pests can have their young trees that are in their critical years of establishment.  These pests should not be ignored; but what are these pests, and how does a grower go about managing them?  Watch this brief interview with Entomology Farm Advisor from the UC Cooperative Extension David Haviland as he explains and read more about it in Pacific Nut Producer Magazine.

     

    Please thank our sponsor Duarte Nursery for their industry support by visiting them at their booth at the following November Events: Tree & Vine Expo, the Grape, Nut & Tree Fruit Expo & Blue Diamond Growers Annual Membership Meeting.

  • BASF Launches Operation Weed Eradication to Help Growers Eradicate Weeds

    BASF launched a new industry-wide initiative to eliminate on-farm weeds. Operation Weed Eradication calls on growers and partners to take action against troublesome weeds in their fields, through cultural practices, chemical control and enhanced diligence.

    Research by Stratus Ag shows that nearly 75 percent of growers nationwide are dealing with glyphosate-resistant weeds in their fields and today’s management practices are not sustainable for long-term control of problem weeds such as pigweed.

    “Our approach to on-farm eradication will uproot problem weeds and help secure a sustainable farming future that builds a successful legacy for seasons and generations to come,” said Scott Kay, Vice President U.S. Crop, BASF Agricultural Solutions. “Weed eradication will be a personalized, tailored journey for each grower with different start and end points. BASF will support growers with expertise and continuous innovation to support this journey.”

    Operation Weed Eradication takes a balanced approach of utilizing cultural practices such as conventional tillage, chemical control such as rotating chemistries, and eradication diligence such as hand weeding to help growers eradicating troublesome on-farm weeds.

    In the coming months, BASF will assemble a coalition of industry leaders, develop a specific eradication customer offering and launch an educational initiative to support its efforts with Operation Weed Eradication.To learn more, please visit

    OperationWeedEradication.com.

  • ACP-HLB Task Force Recommends ACP Treatment in Bakersfield

    To prevent Asian citrus psyllid populations from developing in Kern County this fall, the San Joaquin Valley ACP-HLB Task Force recommends growers with citrus blocks east and south of Bakersfield make a soil-applied imidacloprid treatment or a foliar-applied Actara treatment before mid-September.

    Over the past several years, psyllid detections in Kern County have usually occurred in the fall – starting in September and peaking in October. The San Joaquin Valley ACP-HLB Task Force has been tracking and analyzing psyllid detections to date in Kern County and believes a soil-applied imidacloprid treatment or a foliar-applied Actara treatment will help suppress this historical increase in the fall psyllid population and minimize the risk of Huanglongbing (HLB) transmission.

    In order to protect our citrus from HLB, it is extremely important to keep psyllid populations as low as possible. Last year’s coordinated treatment significantly helped mitigate and suppress this historical increase in the fall psyllid population and inhibit possible transmission of HLB. This is especially important in light of the significant level of HLB-positive citrus trees in Los Angeles, Orange and Riverside counties.

    The San Joaquin Valley ACP-HLB Task Force recommends growers with citrus blocks east and south of Bakersfield should:

    • Treat all of their citrus blocks, including non-bearing trees, located east and south of Bakersfield with imidacloprid (Admire Pro, generic imidacloprid 2F or 4F, etc.) or a foliar-applied Actara treatment.
    • Make the application sometime between mid-August and mid-September.
    • Read and follow all label instructions. Read the University of California’s recommendations.
    • Submit your Pesticide Use Report for this application electronically if possible. If you cannot send electronically, send a copy of the original PUR directly to Kern County grower liaison Judy Zaninovich at jsleslie@msn.com.

    Questions? Contact Judy Zaninovich at jsleslie@msn.com or 559-730-8691.

  • Oaks in Vineyards A ‘Win-Win’ for Bats and Growers

    Californians love their oak trees. During vineyard development, Central Coast grape growers often feel compelled to leave an old iconic oak standing, even if it ends up right in the middle of their vineyard. While driving through the Central Coast, it’s not unusual to see the pattern of vineyard rows broken by a majestic oak tree. Aside from their beauty, what are some of the ecosystem services that these majestic trees provide?

    To find answers, a UC Cooperative Extension scientist in San Luis Obispo County collaborated with a U.S. Forest Service scientist to study how bats use blue oak and valley oak trees in vineyards. UC Cooperative Extension specialist Bill Tietje, a co-author of the study, says they focused on bats that eat insects because bat populations have declined dramatically in some areas due to habitat loss and disease. “And bats don’t hurt grapes. As a matter of fact, thanks to the huge number of bugs they consume—bats could be very good for a vineyard.”

    To understand the potential value of remnant oak trees for insectivorous bats, the researchers placed microphones to detect bat calls within 14 Central Coast vineyards. The recordings revealed 11 species of insectivorous bats foraged within the vineyards and bat foraging activity was 1.5 times greater at the trees compared to open, tree-less areas within the vineyard. And the bigger the tree, the bigger the number of bats it attracted.

    “The study results suggest that the large oak tree in my vineyard not only increases the beauty and biodiversity of the agricultural

    Western red bats, which resemble this eastern red bat, were one of 11 bat species found at oak trees. Photo by Merlin Tuttle

    landscape, but also attracts insect-eating bats that can provide natural pest control—a win-win,” said grape grower Jerry Reaugh, who cooperated with the researchers.

    In fact, the presence of insectivorous bats called woodland-adapted bats more than doubled within the vineyards with trees. The study indicates that the oak trees attracted woodland-adapted bats that would normally be absent from vineyards.

    Tietje hopes that the free insect-reduction services provided by bats will increase grape growers’ incentive to manage and maintain the trees, and even to plant new oak trees in suitable areas around their vineyard, in mutual benefit to both agriculture and biodiversity.

    “In addition to their value for insectivorous bats, remnant trees maintain bird and insect diversity by providing food, habitat, cover and stepping stones that facilitate the movement of wildlife within agricultural landscapes,” said Tietje.

    This study comes at a time when declining blue oak and valley oak populations are of great concern.

    The study by University of Washington graduate student Anne Polyakov, Theodore Weller of USDA Forest Service and Tietje is published in the September 2019 edition of Agriculture, Ecosystems and Environment.

  • Argentine Ant Inhibits Biocontrol Options for Deadly Citrus Pests

    Growers want to minimize their pesticide use in the orchard; but when you have invasive pests like the Argentine Ant protecting aphids and psyllids from natural predators, your options are limited.  Watch this brief interview with Greg Simmons from the USDA-APHIS as he explains and read more about it in California Fresh Fruit Magazine.

  • New detections of West Nile Virus in California horses – Prevention Tips

    California Department of Food & Agriculture — A total of seven California horses have tested positive in recent weeks for West Nile Virus, with six of the cases in the Central Valley and one in Riverside County. Two of the horses were euthanized due to the severity of their symptoms.

    Horse owners are reminded to have their animals vaccinated to make sure they are maximizing protection against the disease. And once vaccinations occur, horse owners should be checking regularly with their veterinarians to make sure they stay current.

    Californians can also do their part to prevent the disease by managing mosquitoes that carry West Nile Virus. Here are some tips:

    • Draining unnecessary standing water found in wheelbarrows, tires, etc.
    • Cleaning water containers at least weekly (i.e., bird baths, plant saucers)
    • Scheduling pasture irrigation to minimize standing water
    • Keeping swimming pools optimally chlorinated and draining water from pool covers
    • Stocking of water tanks with fish that consume mosquito larvae (Contact local mosquito control for assistance) or use mosquito “dunk” available at hardware stores.

    It’s important to remember that mosquitoes become infected with the virus when they feed on infected birds. Mosquitoes then spread the virus to horses.  Horses are a dead-end host and do not spread the virus to other horses or humans. For more information on West Nile Virus, please visit this link.

  • Drilling for Microbial Gold: Eskalen Lab Researchers Seek Biocontrol Agents for Canker Disease

    Marcelo Bustamante, PhD student in Akif Eskalen’s lab, is on a mission.  A sort of microbial safari.  Only the fungi and bacteria Marcelo is collecting aren’t easy to catch-they live inside the grape vine, potentially protecting it from deadly canker disease organisms.  To capture these microbes, Marcelo and his lab mates use a sterile drill bit to drill a small hole in grape vine trunks and cordons, and then carefully collect the sawdust and drill shavings to culture back in the lab for bacteria and fungi.  They sample both diseased and healthy vines.  The hope is that some of these captured microbes will be antagonistic to one or more of the suite of fungal pathogens that comprise a serious disease complex referred to as “grape vine trunk disease” or simply, “canker.”

    Sam Wells and Erin Hardy conducting vine surgery to collect potential biological control organisms-sterile technique in practice!

    Biological control is defined as any activity of one species that reduces the adverse effects of another species.  Living organisms are the agents of biological control, and although we may think of ladybugs and lacewings when we hear the term, bacteria and fungi can be biological control agents too! Microbes can act as antagonists to other microbes, they can out-compete them for nutrients or space, or they can secrete products that inhibit their growth.  In fact, many biologically based pesticides harness the products of microbes, (think Bt or Spinosad).

    The target of this biocontrol search is a formidable one.  Grapevine trunk disease is present in nearly every mature vineyard, shortening its life and productivity.  Some have even referred to the trunk disease epidemic as the “next phylloxera,” because the disease is so devastating to vineyards.

    The disease is caused by several fungi, all entering the vine via spores carried by rain on pruning wounds. Esca (called measles for the spotting on the fruit), Eutypa dieback, Botryosphaeria dieback, and Phomopsis, are all considered grapevine “trunk diseases”-infection can run from the pruning wound all the way into the trunk.  The disease weakens spurs and shoots, in some cases  killing them. Yield and grape quality is decreased.  Eventually, diseased vines are no longer worth keeping in the vineyard and need to be pulled and replanted.

    Esca, a grapevine trunk disease caused by several fungi, causes “tiger stripe” leaf symptoms and spotted fruit that can’t be harvested.

    Since pruning wounds can be susceptible to infection for weeks after pruning, the recommended practices to prevent infection are to prune late, to “double” prune, that is, make an initial pass in winter leaving 12-14 inches-this can be done mechanically-and then come back closer to budbreak when rains are less frequent to do the final pruning cuts, and to apply fungicide “protectants” to pruning wounds.  Growers should also remove all infected prunings from the vineyard, minimize stress to new plantings and carefully inspect new planting material to be sure it is free from pathogens.  Although most growers I know do practice late and double pruning, which is also helpful to prevent frost damage, once the disease is in a vineyard, it is difficult to prevent spread.

    Enter the Eskalen lab! A group of UC Davis students studying plant pathology under scientist Akif Eskalen to help solve agricultural plant disease problems! Akif has recently taken the position of UC Plant Pathology Specialist, replacing the late Doug Gubler, and we are so fortunate to have him! Under Akif’s direction, Marcelo will be culturing probably hundreds of microbes collected from vines.  He’ll screen them in the lab, and, fingers crossed, he’ll find a few that show promising biological control against canker.  Maybe, just maybe, he’ll find some foothill microbial gold.  I’ll keep you posted…

    By Lynn Wunderlich

  • Techniques in Organic Farming that Influence Soil Health

    Soil organic matter has long been known to benefit farmers. The carbon in this organic matter acts as a food source for soil microbes, which then provide other nutrients to the crops grown. Microbes, insects and small soil critters produce materials that can improve soil structure and water retention. It’s a healthy ecosystem every farmer wants to encourage.

    Measuring changes in soil organic matter can be a challenge in intensively tilled soil that is used for vegetable production. Even in production systems with less soil disturbance, soil organic matter changes slowly. But, Eric Brennan and Veronica Acosta-Martinez are testing for soil enzymes as early indicators of improvements in soil health in a long-term systems study.

    Brennan manages the study in an area of California known as the “Salad Bowl of the World.” The Salinas Valley has high-input, organic vegetable production systems. “Farms in Salinas usually need to produce two or more vegetable crops per field annually to be profitable,” says Brennan. “This production intensity complicates the adoption of winter cover cropping. This is why many farmers in this region prefer to use compost to add large amounts of organic matter to the soil.”

    Specifically, the team compared farming systems that received different amounts and types of organic matter. The sources were from compost and cover crops. They recently published their results in the Soil Science Society of America Journal.

    “Our results on soil enzyme activity illustrate the importance of frequent cover-cropping in tillage-intensive, organic vegetable production,” says Brennan. “This raises questions about the sustainability of organic and conventional vegetable systems if cover crops are seldom used. We need to find innovative strategies to help farmers increase cover cropping. The practice is shown to improve soil health. It also provides other benefits like reducing nitrogen leaching into ground water.”

    It’s not that organic or conventional farmers in this region are against cover cropping. It’s that their use can complicate many aspects of vegetable production.

    Brennan’s study showed that cover cropping annually – no matter the type of plant grown – greatly benefits the soil. The study found that annual inputs of compost have relatively small benefits. There was an increase in microbial activity with compost, but not as much as with annual cover crops.

    There are some caveats in the study. This research was conducted in a loamy sand soil in Salinas Valley. Organic farmers in different regions may have different results. Using different types of fertilizers could impact results, as well.

    “The growing body of information from this long-term trial challenges the overly-simplistic notion that certified organic management improves soil health or quality,” says Brennan. He adds that the USDA organic standards require that certified farms show that their tillage and cultivation practices maintain or improve soil conditions. This refers to physical, chemical and biological factors. It also refers to minimizing soil erosion, which can worsen with intensive tilling.

    The team hopes that future research will focus on different soil types, such a clay or loam soil. Evaluating changes over shorter increments would provide useful data, too. The soil enzyme data tells one part of the interesting story of this relatively long-term experiment.

    Read more about this research in the Soil Science Society of America Journal. This research was funded primarily by the USDA-ARS, but also received 2 years of initial funding from a Specialty Crops grant from the California Department of Food and Agriculture.

    To watch a 5-minute video of Eric Brennan explaining the Salad Bowl of the World, visityoutube.com/watch?v=M-8tCXXKqNA.