Cooperative Extension San Joaquin County
University of California
Cooperative Extension San Joaquin County

Posts Tagged: Peaches

IPM information extends to apple and peach growers in Guatemala

Peach trees in the highlands of Guatemala with a view of the Santa Maria Volcano in the distance.
Did you know that apples and peaches are two important fruit crops planted in the highlands of Guatemala? More than 7,600 acres of apples and 6,100 acres of peaches are grown. However, with warm winters that don't allow for the winter chilling time that these crops require for optimal growth, and with freezing spring temperatures along with summer rains, growing apples and peaches in this area is often a challenge for growers.  

As part of the Farmer-to-Farmer Program sponsored by the Partners of the Americas and funded by the United States Agency for International Development (USAID), retired UC IPM entomologist Walter Bentley and Washington State University entomologist Jay Brunner traveled to Guatemala in April to help growers improve the peach and apple industry. Their primary goal was to identify pest problems and possible solutions to help peach and apple growers improve fruit production, taking into account the region's unique climate.

Jay Brunner (far left), Walter Bentley and Armando Hernandez (center), with family members from one of the farms visited.
Bentley and Brunner worked with the Asociación Nacional de Productores de Frutales Deciduos (ANAPDE) and its director, Armando Hernandez, to reach out to various growers in the area. Bentley and Brunner set out to identify insect and mite problems. Fortunately, they found that there were only a few entomological problems.

“The most important issues were horticultural,” said Bentley. “The region's biggest need is for a horticulturist or plant pathologist.”

Some of the peach varieties require 300 to 500 chilling hours.

Top half of a peach tree in bloom while the bottom half produces fruit, caused by the lack of required winter chilling hours.
However, with the warm winters, Bentley observed that peach trees growing in the regions of Quetzaltenango and Chichicastenango of Guatemala do not receive the required winter chilling hours, resulting in an extended bloom period.

“Peach trees at elevations of 7,500 to 9,000 feet above sea level bloom for 2 months whereas bloom in California lasts just 10 days," he said. "You would get situations where the top half of the tree was in bloom while the bottom half was already producing fruit.”

This creates an environment favoring disease development and causing further problems for growers if the disease was severe enough to warrant a pesticide treatment. If a tree was partially in bloom while simultaneously producing fruit, it would have to be hand-sprayed multiple times so that the portion of the tree that warranted treatment was sprayed.

Walter Bentley shows examples of phytophthora root rot from the UC Integrated Pest Management for Stone Fruits manual.
Summer rains create further problems in the area, causing favorable conditions for pathogens to develop, especially at harvest. Brown rot, Phytophthora and rust are the three main diseases attacking apples and peaches in these regions.

Although most of the important issues that Bentley and Brunner found were horticultural or disease-related, there were some insect problems. Many growers had stink bugs and other plant bugs attacking their trees. Spider mites and predatory mites were also observed. Growers sprayed pyrethroids after bloom to help prevent plant bug damage. However, applying pyrethroids reduced predatory mites, leading to an outbreak of spider mites.

After spending seven days touring four to six farms per day and looking at various practices, Bentley and Brunner spent the next week leading workshops for farmers and discussing integrated pest management (IPM) approaches to managing problems. Using the UC IPM website, specifically the Pest Management Guidelines for apples and peaches, Bentley and Brunner were able to teach sampling methods, stress the importance of correct pest identification, and encourage growers to spray with the least toxic and disruptive products. Bentley and Brunner were surprised by the large variety of pesticides available to growers, but were encouraged that farmers were willing to spray only when necessary while being open to other methods of control.

ANAPDE Director, Armando Hernandez, searches for predatory mites on peaches.
Both entomologists plan to keep the lines of communication open and feel the observations made during this trip could lead to future visits where sustainable pest management programs can be put into action. For example, predatory mites were observed in several of the orchards. This could lead to developing a biological control program to control spider mites.

Bentley and Brunner were impressed by the staff that took them around to each farm and by the growers who were receptive to new ways of managing pest problems. The farmers were very appreciative of the advice they received and were very generous. “Everywhere you went people wanted to share what they had,” said Bentley. “They are amazing people.”

Humbled by the experience, Bentley reflected, “I'm glad I went. I've been given a lot in my life and wanted to give back a little.”

Posted on Friday, July 8, 2016 at 10:00 AM
Tags: Apples (1), Guatemala (1), Peaches (3), Walter Bentley (1)

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
 
E-mail
 
Webmaster Email: mdhachman@ucdavis.edu