Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
Division of Agriculture and Natural Resources
University of California
Division of Agriculture and Natural Resources

Posts Tagged: walnuts

Almond and Walnut Pest Management Guidelines revised just in time for the holidays

‘Tis the season for baking lots of tasty treats. Breads, cookies, cakes, and candy are just a few that come to mind. What makes many of these treats so tasty is the addition of almonds or walnuts to the list of ingredients.

In California, we are lucky to be at the center of almond and walnut production. According to the California Department of Food and Agriculture's (CDFA's) latest Agricultural Statistics Review, more than 99 percent of the almonds and walnuts produced in the United States are grown in California.

Almond and walnut growers work tirelessly to supply enough nuts to not only satisfy domestic demand, but also for export. Worldwide, almonds rank as the largest specialty crop export. California is the top almond producer in the world, accounting for about 80 percent of all almonds grown. For walnuts, California ranks as the second largest producer in the world. To keep up with this demand, almond and walnut growers must be constantly aware of pests, diseases, and abiotic problems that can affect the tree and growing nuts.

California is the top almond producer in the world, accounting for about 80% of all almonds grown. (Photo: Jack Kelly Clark)

The University of California Statewide Integrated Pest Management Program (UC IPM) has recently published revised Pest Management Guidelines for almonds and walnuts, helping growers prevent and manage pest problems with the most up-to-date information.

Revisions in the Almond Pest Management Guidelines include:

  • A new section on bacterial spot, a new disease of almond in California found in the Sacramento and northern San Joaquin valleys
  • A renamed section on fruit russeting, revised from the old powdery mildew section
  • Significant revisions made to the management section of navel orangeworm, one of the major pests attacking California almonds
  • Improvements on how to do dormant spur sampling section with easier-to-understand information on monitoring and thresholds
Bacterial spot on almond, a new disease of almond in California. (Photo: Brent A. Holtz)

Revisions in the Walnut Pest Management Guidelines include:

  • Updated information on the association between walnut twig beetle and thousand cankers disease
  • New sections for Botryosphaeria and Phomopsis cankers, branch wilt, and paradox canker
  • Significant changes to the walnut husk fly management section
Male (left) and female walnut twig beetles. (Photo: Larry L. Strand)

Both the almond and walnut revised Pest Management Guidelines also include updated information on fungicide efficacy, weed management, and vertebrate management.

Authored by University of California specialists and advisors, the Pest Management Guidelines are UC's official guidelines for monitoring and managing pests in California crops. For more information on pest management in these or other crops, visit the UC IPM website.

Posted on Tuesday, December 19, 2017 at 11:03 AM
Tags: almonds (4), pests (1), walnuts (10)

New cost study for English walnuts released by Agricultural Issues Center

This cost study focuses on establishing a walnut orchard in the Sacramento Valley
A new study on the cost and return of growing English walnuts has been released by UC Agriculture and Natural Resources' Agricultural Issues Center.
 
The study focuses on establishing an orchard and producing walnuts under microsprinkler irrigation in the Sacramento Valley. 

The economic life of the orchard used in this cost analysis is 30 years. The analysis is based upon a hypothetical farm operation of a well-managed orchard, using practices common to the region. Growers, UC ANR Cooperative Extension farm advisors and other agricultural associates provided input and reviews. Assumptions used to identify current costs for the walnut crop, material inputs, cash and non-cash overhead are described. A ranging analysis table shows profits over a range of prices and yields. Other tables show the monthly cash costs, the costs and returns per acre, hourly equipment costs, and the whole farm annual equipment, investment and business overhead costs.

The new study is titled 2015 Sample Costs to Establish and Produce English Walnuts in the Sacramento Valley, Microsprinkler Irrigated.”

This study and other sample cost of production studies for many commodities are available. They can be downloaded for free from the UC Davis Department of Agriculture and Resource Economics website at http://coststudies.ucdavis.edu.

For additional information or an explanation of the calculations used in the studies, contact Don Stewart at the UC ANR Agricultural Issues Center at (530) 752-4651 or destewart@ucdavis.edu.

Posted on Monday, November 16, 2015 at 9:10 AM

Bats in the belfry? No, bats in walnut orchards

A pallid bat catching dinner mid air. (Photo: Bat Conservation International)
Bats are voracious predators of night-flying insects that target California crops. Research statistics show that a pregnant or nursing female can consume as much as two-thirds of her body weight in insects per night. That's somewhat like a 150-pound man eating 100 pounds of food per day.

What's the economic value of bats to the agricultural pest control? It probably exceeds $23 billion per year, according to recent studies. However, very little data exists on the benefits of bats for individual crops, such as walnuts.

UC Agriculture and Natural Resources researchers, together with UC Davis, are launching a survey to better understand the value of bats (and birds) on managed lands. The voluntary survey, focused on growers and landowners in California's Central Valley, may be completed online.

Work is already underway to assess the pest-control impact of bats on walnut production in the Central Valley with a grant from the U.S. Environmental Protection Agency STAR (Science to Achieve Results).

California produces almost all of the nation's walnuts. Farmers grow some 500,000 tons of walnuts on 290,000 acres, with the annual crop valued at $1.8 billion. Due to popular demand, new orchards are planted every year, calling for more intensive farming practices to manage costly crop pests. For walnuts, the key pest is the codling moth, a larva that feeds on developing nuts. The adult moths begin to fly and lay eggs on the nutlets in May and produce up to four generations per year.

Rachael Long with a bat detector under the Davis causeway. (Photo: California Farm Bureau)
Growers, as part of their pest control management practices, typically use insecticides, spraying once or twice a year for this pest. Many also use pheromones, a mating-disruption technology that prevents males from finding females. Although generally effective, pesticides are expensive and they can have harmful impacts on the environment.

Bats forage in walnut orchards for codling moths and other insects. Colonies of bats double their activity on farms when they roost in bat houses attached to barns in the orchards. The Mexican free-tailed bat is the most abundant species, followed by the Yuma and California myotis, and five other species, including the pallid bat.

In an effort to quantify the economic impact of bats' consumption of codling moths, we captured 36 Mexican free-tailed bats over a three-night period in an 80-acre walnut orchard in Yolo County. Some 3,000 bats live in the bat houses in an abandoned shop on the property.

The research procedure: We opened our mist net from 11 p.m. to 2 a.m. to correspond with codling moth flights and bat activity, and captured the bats as they returned to the roost after feeding. We placed the bats individually in sterile cloth sacks and kept them there until they defecated, then we released them. We quickly froze the guano pellets and shipped them to a USDA lab, where scientists genetically tested them for the presence of codling moths.

Our preliminary data suggest that 5 percent of these bats – about 150 bats from this colony of 3,000 – consumed at least one codling moth per night. We calculated 30 nights per generation for the codling moth, and four generations per year, with each female moth laying 60 viable eggs on individual nuts.

Bats help protect California walnuts from coddling moth.
For a typical 80-acre walnut orchard producing a total of 136 tons of walnuts per year, we estimate that bats can protect about 6 percent of the crop yield, or $29,700 worth of walnuts per season at the current price of $1.65 per pound. That's an economic value of $10 per bat per year. And that figure probably underestimates the true value, since for some species of bats, up to 40 percent of their diet can consist of moths – an average of about 15 moths per night.

The next steps: we are refining our economic data and determining whether these insect-hunting bats help reduce pesticide use in walnut orchards.

Bats provide these pest control services for free while farmers enjoy a decrease of pests in their orchards and an increase in profits.

Co-authors: Rachael Long, UC ANR advisor; and Katherine Ingram, Department of Wildlife, Fish and Conservation Biology, UC Davis.

Posted on Wednesday, April 15, 2015 at 8:22 AM
Tags: bats (1), Rachael Long (1), walnuts (10)

UC estimates production costs for walnuts, wine grapes, hay, blackeye beans

UC now has cost estimates for growing conventional and organic walnuts.
New studies showing production costs for conventionally and organically grown walnuts, organic alfalfa hay, wine grapes and single- and double-cropped blackeye beans are now available from the University of California Cooperative Extension.

Each analysis is based upon hypothetical farm operations using practices common in the region. Input and reviews were provided by UC Cooperative Extension farm advisors, researchers, growers, farm accountants, pest control advisers, consultants and other agricultural associates.

Each report describes the assumptions used to identify current costs for the individual crops, material inputs, cash and non-cash overhead. A ranging analysis table shows profits over a range of prices and yields. Other tables show the monthly cash costs, the costs and returns per acre, hourly equipment costs, and the whole farm annual equipment, investment and business overhead costs.

The six new cost studies are the following:

  • Sample Costs to Produce Organic Walnuts, 2013, North Coast by Rachel B. Elkins, Karen M. Klonsky and Richard L. De Moura.
  • Sample Costs to Produce Organic Alfalfa Hay, 2013, California by Rachael F. Long, Steve B. Orloff, Karen M. Klonsky and Richard L. De Moura.
  • Sample Costs to Establish and Produce Walnuts, 2013, Northern San Joaquin Valley by Joseph A. Grant, Janet L. Caprile, David A. Doll, Kathleen Kelly Anderson, Karen M. Klonsky and Richard L. De Moura.
  • Sample Costs to Establish and Produce Wine Grapes, 2013, Sacramento Valley by Chuck A. Ingels, Karen M. Klonsky and Richard L. De Moura.
  • Sample Costs to Produce Blackeye Beans (double-cropped), 2013, Southern San Joaquin Valley and Sample Costs to Produce Blackeye Beans (single-cropped), 2013, Southern San Joaquin Valley by Carol A. Frate, Karen M. Klonsky and Richard L. De Moura.

The cost of production studies for these and other crops are available online at http://coststudies.ucdavis.edu, at UC Cooperative Extension offices or by calling (530) 752-3589.

For additional information about the studies, contact Richard De Moura at rdemoura@ucdavis.edu.

 

Posted on Tuesday, July 9, 2013 at 3:48 PM

UC studies examine costs for growing pears, walnuts, winegrapes

UC studies examine costs for growing pears, walnuts, winegrapes

UC has cost estimates for growing pears conventionally and organically.
New studies showing production costs for pears, organic pears, walnuts and cabernet sauvignon winegrapes are now available from the University of California Cooperative Extension.

Analysis for each crop is based upon hypothetical farm operations using practices common in the region. Input and reviews were provided by UC Cooperative Extension farm advisors, researchers, growers, farm accountants, pest control advisers, consultants and other agricultural associates.

The studies describe the assumptions used to identify current costs for the individual crops, material inputs, cash and non-cash overhead. A ranging analysis table shows profits over a range of prices and yields.  Other tables show the monthly cash costs, the costs and returns per acre, hourly equipment costs and the whole farm annual equipment, investment and business overhead costs.

The four new cost studies are the following:

  • Sample Costs to Establish and Produce Pears, 2012, North Coast, by Rachel B. Elkins, Karen M. Klonsky and Kabir P. Tumber.
  • Sample Costs to Produce Organic Pears, 2012, Sacramento Valley, by Chuck A. Ingels and Karen M. Klonsky.
  • Sample Costs to Establish a Walnut Orchard and Produce Walnuts, 2012, North Coast, by Rachel B. Elkins, Karen M. Klonsky and Kabir P. Tumber.
  • Sample Costs to Establish a Vineyard and Produce Winegrapes (Cabernet Sauvignon), 2012, San Joaquin Valley North, by Paul S. Verdegaal,  Karen M. Klonsky and Richard L. De Moura.

These cost studies and cost of production studies for other crops are available online at http://coststudies.ucdavis.edu, at UC Cooperative Extension offices and by calling (530) 752-3589. For more information about the studies, contact Richard De Moura at rdemoura@ucdavis.edu in the UC Davis Department of Agricultural and Resource Economics.

Posted on Friday, September 7, 2012 at 5:36 PM
Tags: costs (1), pears (1), walnuts (10), winegrapes (2)

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