Pest pressures challenge organics future

  • May 1st, 2013

The favorable climate and relatively low pest and disease pressure in the arid West have been blessings for organic tree fruit growers. Those conditions explain why more than 95 percent of the nation’s organic apple production comes from Washington, California, Arizona, Colorado, and Oregon. But increasing pest challenges and [...]

  • New grape disease reduces yields, quality

New grape disease reduces yields, quality

  • April 1st, 2013

Left: A Merlot grapevine shows redleaf symptoms on mature leaves in the lower portions of the canopy. Symptoms are easily confused with grapevine leafroll disease. Right: Cabernet Franc clusters from a single vine show infection on the left, nonsymptomatic cluster on the right.

A new disease that threatens the health [...]

  • Kill the pathogen

Kill the pathogen

  • March 15th, 2013

Apple scab is a serious problem in humid climates, and McIntosh is very susceptible. Lesions occur on both leaves and fruit.
PHOTO COURTESY OF GEORGE SUNDIN

Apple growers have three new fungicides they can use to control apple scab, and Dr. George Sundin would like to see growers keep them.

“Use [...]

  • Developing a disease management program

Developing a disease management program

  • March 15th, 2013

Washington State University viticulture extension specialist Dr. Michelle Moyer suggests growers consider the following when developing a ­disease management program:

•    Reproductive rate of the pathogen. How fast can the disease reproduce in your vineyard? Is weather conducive to reproduction?
•    Speed of your reaction time. Do you have enough [...]

  • Living with cherry diseases

Living with cherry diseases

  • March 15th, 2013

Little cherry disease made a dramatic resurgence in Washington in 2010 and has since spread rapidly. These Sweetheart cherries show symptoms of small and puny fruit.
PHOTO BY KEN EASTWELL

With no cure for cherry trees infected with most viruses—short of cutting them out of the orchard—Washington State University researchers [...]

Preventing mildew

  • March 15th, 2013

Guide for grape pest management available
Washington State University’s 2013 Grape Pest Management Guide includes recommendations for controlling insects, weeds, diseases, and other pests. The guide also includes results of 2012 fungicide efficacy trials, a table with Fungicide Resistance Action Committee (FRAC) codes for resistance management, and suggestions of [...]

  • Working with copper

Working with copper

  • March 15th, 2013

Copper is a potent spray chemical, useful on many stone and pome fruits. It is active against bacterial diseases like fireblight, bacterial canker, and bacterial spot, and fungal diseases like cherry leaf spot, peach leaf curl, and apple scab as well.

Used correctly, copper sprays, especially very early in the [...]

  • Bacterial canker

Bacterial canker

  • March 1st, 2013

The weather turned hot and dry—­conditions conducive to healing the cuts without making the canker situation worse. Then, the recommended approach was to make two fall sprays of copper, with two more copper sprays recommended before bud break this spring.
12 STEPS TO MANAGE BACTERIAL CANKER
In Oregon, bacterial [...]

  • Identifying grape shrivels

Identifying grape shrivels

  • February 15th, 2013

In the past, grape growers have mistaken any shrivel in their fruit for grape berry shrivel, also known as sour shrivel, says Washington State University’s Dr. Bhaskar Bondada. In a panic, some were needlessly thinning clusters to remove what they thought were berries afflicted with sour shrivel.

It’s important to [...]

  • Turning on a plant’s defenses

Turning on a plant’s defenses

  • February 15th, 2013

New technology is coming to the apple and pear industry to help control fireblight. Actigard is a systemic compound with a unique mode of action that mimics the natural systemic-activated resistance response found in many plants. When applied preventatively, much like vaccinations are given to humans to ward off [...]

  • Coppers are a fit for organics

Coppers are a fit for organics

  • February 15th, 2013

Before the 1960s, there were no antibiotics to help orchardists control fireblight, one of the most destructive diseases of pears and apples. Copper materials were the mainstay back then.

But coppers are returning as fireblight control products, particularly for organic orchardists. Oxytetracycline, an effective antibiotic, could lose its place on [...]

  • Fireblight is native to North America

Fireblight is native to North America

  • February 15th, 2013

Fireblight is a plant disease of apples and pears caused by the bacterium Erwinia amylovora. It is native to North America where it resides in wild hosts such as crab apple and hawthorn. Over the decades, it has spread to other pome fruit producing regions in Europe, the Middle [...]