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Posts Tagged: pests

Katja Poveda: Zeroing in on Plant-Insect Interactions

Katja Poveda (left), assistant professor of entomology at Cornell, working on potatoes in her greenhouse.

Let's consider plant-insect interactions in agro-ecosystems. That's what Katja Poveda, assistant professor of entomology, Cornell University,...

Katja Poveda (left), assistant professor of entomology at Cornell, working on potatoes in her greenhouse.
Katja Poveda (left), assistant professor of entomology at Cornell, working on potatoes in her greenhouse.

Katja Poveda (left), assistant professor of entomology at Cornell, working on potatoes in her greenhouse.

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 (59), pests (7), walnuts (11)

Top 10 pests in gardens and landscapes and how to control them

Download the free booklet at the bottom of the page!

1. Ants

Most people deal with ants around their home at some point. Because most ants live outdoors, focus efforts on keeping ants from entering buildings by caulking entryways. Follow good sanitation practices to make your home less attractive to ants. Spraying ants inside the home will not prevent more ants from entering. Use baits to control the ant colony. Pesticide baits work by attracting worker ants who then take the poison back to the nest where the entire colony, including queens, can be killed. In the landscape, ants protect honeydew-producing pest insects from predators, so use sticky barriers or insecticide baits to keep ants out of trees and shrubs.

 

2. Aphids

Aphids can curl leaves and produce sticky honeydew, but they rarely kill plants and you usually can wash them off with water. When aphid numbers get high, natural enemies such as lady beetles (lady bugs), lacewings, syrphid fly larvae, soldier beetles and others frequently feed on them, eliminating the need for pesticides. Protect these good bugs by avoiding the use of insecticides that can be toxic to a broad variety of insects. Ants protect aphids from these natural enemies, so keep ants away from your garden as well. When pesticides are necessary, use less toxic products such as insecticidal soaps and oils.

 

3. Asian citrus psyllid and Huanglongbing disease

The Asian citrus psyllid (ACP) and the deadly bacterial disease it spreads, Huanglongbing (HLB), threaten citrus trees in backyards and on farms. There is no cure or effective control method for HLB disease.  All types of citrus—including oranges, grapefruit, lemons, and mandarins—are affected as well as a few closely related ornamentals. ACP and HLB have already devastated the Florida citrus industry, and now that it is in the Western U.S. it is threatening the California citrus industry as well.

 

4. Gophers

Gophers are small burrowing rodents that feed on roots of many types of plants. A single gopher can ruin a garden in a short time, and gopher gnawing can damage irrigation lines and sprinkler systems. In lawns, their mounds are unsightly and interfere with mowing. Early detection is critical to prevent damage. Use both traps and underground fencing to manage gopher problems. Toxic baits are available but can pose threats to wildlife, pets, and children, especially in backyard situations.

 

5. Leaf-feeding caterpillars

Caterpillars, which are the larvae of butterflies and moths, damage plants by chewing on leaves, flowers, shoots, and fruit. Caterpillars in fruit or wood can be difficult to manage because they are hidden most of their life and can cause serious damage even when numbers are low. However, many plants, especially perennials, can tolerate substantial leaf damage, so a few leaf-feeding caterpillars often aren't a concern. Handpicking and beneficial predators and parasites often provide sufficient control. Look for feeding holes, excrement, webbed or rolled leaves, caterpillars, eggs, and good bugs.

 

6. Peach leaf curl

Peach leaf curl is a fungal disease that affects only peach and nectarine trees. Distorted, reddened foliage in the spring is a distinctive symptom. New leaves and shoots thicken and pucker and later may die and fall off. An infection that continues untreated for several years can lead to a tree's decline. To prevent peach leaf curl, treat peach and nectarine trees with a copper fungicide every year after leaves fall. After symptoms appear in the spring, any treatment will not be effective. When planting new trees, consider buying peach tree varieties that are resistant to the disease.

 

7. Rats

Rats eat and contaminate food, garden produce, and fruit, and transmit diseases to humans and pets. Manage rats by removing food and shelter, eliminating entryways into buildings, and trapping. Snap traps are the safest, most effective, and most economical way to trap rats. For Norway rats, place traps close to walls, behind objects, in dark corners, and in places where you have found rat droppings. For roof rats, place traps in off-the-ground locations such as ledges, shelves, branches, fences, pipes, or overhead beams. Ensure traps are out of reach of children and pets.

 

8. Scales

Scale insects suck plant juices and are pests of many trees and shrubs. Infestations can cause yellowing or premature dropping of leaves, sticky honeydew, and blackish sooty mold. Plant parts can distort or die back, depending on the species and abundance of scales. Most plants tolerate low to moderate numbers of scales. Provide plants with proper cultural care, especially irrigation. Encourage scale predators such as lady beetles or lacewings and look for parasite emergence holes in scale covers. Use sticky barriers or insecticide baits to selectively control scale-tending ants. Consider replacing problem-prone plants because most scales are highly specific to certain plants.

 

9. Snails and slugs

These slimy mollusks emerge from hiding at night and chew holes in leaves and flowers of many succulent garden plants and fruit. Management requires a vigilant and integrated approach that includes eliminating moisture and hiding spots, trapping, setting up barriers, and handpicking. Regularly remove snails from shelters you can't eliminate such as low ledges on fences, undersides of decks, and meter boxes. Place traps in your garden and dispose of trapped snails and slugs daily. Reduce moist surfaces by switching to drip irrigation or watering in the morning rather than later in the day. Consider snail-proof plants such as impatiens, geraniums, begonias, lantana, nasturtiums, and many plants with stiff leaves and highly scented foliage such as sage, rosemary, and lavender.

 

10. Weeds in landscapes

Prevent weed invasions in new beds with good site preparation. Keep weeds out with an integrated program that includes competitive plants, mulches, and hand removal. Be particularly vigilant about removing aggressive perennial weeds. You rarely should need herbicides in established landscape plantings. Mulches prevent weed seed germination by blocking sunlight. Remove small weeds by hand before they flower and set seed. Use shallow cultivation or hoeing to remove annual weeds from ornamental plantings. Only use herbicides for special-problem situations before establishing new plantings or for difficult-to-control perennial weeds.

 

To see all of the University of California's Statewide Integrated Pest Management Program's information on home, garden, and landscape pests, visit http://www.ipm.ucanr.edu/PMG/menu.homegarden.html

For other short pest “Quick Tips” like the ten above, see http://www.ipm.ucanr.edu/QT/

 To read even more in-depth, peer-reviewed information on many other common home and landscape pests in California, see the Pest Notes series at http://www.ipm.ucanr.edu/PMG/PESTNOTES/index.html

Download your free UC IPM Quick Tips Booklet of the Top Ten Pests in Gardens and Landscapes and How to Control Them with the link below! 

Posted on Friday, June 10, 2016 at 12:30 PM
  • Author: Tyler Ash

Our Bees Deserve The Best

Extension apiculturist Eric Mussen (now emeritus, shows visitors the inside of a hive at the Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis. (Photo by Kathy Keatley Garvey)

This is National Pollinator Week and what better time to post some bee wisdom from Cooperative Extension apiculturist (now emeritus) Eric...

Extension apiculturist Eric Mussen (now emeritus, shows visitors the inside of a hive at the Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis. (Photo by Kathy Keatley Garvey)
Extension apiculturist Eric Mussen (now emeritus, shows visitors the inside of a hive at the Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis. (Photo by Kathy Keatley Garvey)

Extension apiculturist Eric Mussen (now emeritus, shows visitors the inside of a hive at the Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis. (Photo by Kathy Keatley Garvey)

Extension apiculturist (now retired) Eric Mussen explains bees. (Photo by Kathy Keatley Garvey)
Extension apiculturist (now retired) Eric Mussen explains bees. (Photo by Kathy Keatley Garvey)

Extension apiculturist (now retired) Eric Mussen explains bees. (Photo by Kathy Keatley Garvey)

Inside the hive: the queen bee goes about laying eggs as worker bees tend to her needs and the needs of the colony. (Photo by Kathy Keatley Garvey)
Inside the hive: the queen bee goes about laying eggs as worker bees tend to her needs and the needs of the colony. (Photo by Kathy Keatley Garvey)

Inside the hive: the queen bee goes about laying eggs as worker bees tend to her needs and the needs of the colony. (Photo by Kathy Keatley Garvey)

Posted on Wednesday, June 17, 2015 at 5:20 PM
Tags: diseases (1), Eric Mussen (266), honey bees (356), malnutrition (2), National Pollinator Week (20), parasites (2), pesticides (14), pests (7), stress (1)

Broccoli Success

Recently, in Late September, we harvested our first broccoli (Brassica oleracea) head of the season. It tasted so good! I planted a 4” transplant in early September and it really took off. At the same time I planted a six pack of ‘Green Comet” and as we head into the third week of October, we are picking them one by one. Of all the winter vegetables, broccoli is my favorite because it just keeps on producing. First the large center head then a week to ten days later the side shoots. The shoots get smaller and smaller with each harvest. Finally the shoots are so small they are hardly worth cooking so I just throw them into salads. A bonus of broccoli is the leaves are tasty, too. We add them to our vegetable smoothies.

The biggest problem I have encountered growing broccoli is the imported cabbage worm. When I see white butterflies with one or two spots on their wings fluttering around the garden I take heed! It is the Cabbage Butterfly (Pieris rapae) laying eggs on the underside of the leaf. Males have one spot on each wing and females have two. The larvae are little velvety-green imported cabbage worms so named because they feed on members of the cabbage family (Cruciferae), and believe me they can do lots of damage to the leaves plus get right into the heads. Over the years I have tried a number of methods to deal with the little pests. First I ignored them. That didn’t work out so well as the leaves had big holes in them and the florets harbored little green worms. I picked them out as best I could before I cooked the broccoli but occasionally I missed one and it showed up as a brown cooked worm on the plate. Yuck! My family did not appreciate them!

My second method was to pick off the eggs on the underside of the leaves. They are little yellowish bullet shaped single eggs and fairly easy to see. That was a lot of work and I missed some which left me with the same problem as method #1. So, one year I tried method #3. I used row covers to keep the butterflies out. But, a few sneaky butterflies got under the cover and had their way with my broccoli. I didn’t realize I had a problem until it was too late because I was sure my precious plants were protected and therefore didn’t check the leaves for eggs. It turned out worse than method #1or #2. Now I use method #4 and the broccoli is beautiful with minimal holes in the leaves and no little green worms in the florets or on my plate.

Method #4. I don’t like the hassle of mixing and spraying pesticides on my garden, but I have finally zeroed in on a successful method to deal with the little green caterpillar/worms. When I see the white butterflies I know the green worms will follow in three to five days and they will take two to three weeks to mature so I mix the liquid concentrate B.t. (Bacillus thuringiensis) and spray. B.t. is an organic product that I first used way back in the 70s when I started vegetable gardening (it was a powder then). I spray a very fine mist on the leaves once every 5 to 7 days while the butterflies are active. I try to be vigilant as there can be two to four generations in the spring and fall.

Here is a little secret. Use use Spray- Grip along with B.t. because the spray will not bead up and run off the leaves but will adhere to the leaves and turn them a darker green while the spray is wet so you know which plant you have covered. B.t. is a natural bacterium and needs to be used up the day it is mixed. It only kills the caterpillars or worms feeding on the plant and will not harm birds, earthworms or other beneficial insects such as honey bees and ladybugs. Plus, it can be used up to and on the day of harvest. There is only one thing that would make this method easier and that is to be able to purchase the spray pre mixed and not have to use it up each time. Well, guess what? That is exactly what is coming this spring to our nursery. That is a product I will be watching for to ensure success with broccoli.

Female Cabbage Butterfly (Pieris rapae). (photos by Libbey McKendry)
Female Cabbage Butterfly (Pieris rapae). (photos by Libbey McKendry)

The larvae are little velvety-green imported cabbage worms.
The larvae are little velvety-green imported cabbage worms.

Leaf damage when left alone.
Leaf damage when left alone.

Broccoli Success!
Broccoli Success!

Posted on Monday, November 4, 2013 at 3:51 PM
Tags: broccoli (2), cabbage butterfly (1), pests (7)

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