The oystershell scale is a very small brown or gray-brown insect that attaches to the bark of trees and shrubs, giving the overall appearance of an oyster's shell. Since the insect can kill plant cells as it feeds on sap, branches or sometimes the whole plant can be killed. Oystershell scale also may weaken plants, allowing disease organisms, such as cytospora, to be established. Pictured is an oystershell problem on a aspen tree.

Courtesy Photo

The oystershell scale is a very small brown or gray-brown insect that attaches to the bark of trees and shrubs, giving the overall appearance of an oyster's shell. Since the insect can kill plant cells as it feeds on sap, branches or sometimes the whole plant can be killed. Oystershell scale also may weaken plants, allowing disease organisms, such as cytospora, to be established. Pictured is an oystershell problem on a aspen tree.

Looking for ways to rejuvenate your pasture?

Colorado State University Extension offers information about hay production, insect infestation

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Pasture and hay production and the oystershell scale insect - while unrelated, they're important issues for Moffat County residents, especially with spring just around the corner.

After years of drought, ranchers are looking for ways to rejuvenate their pasture and hay ground. With the high price of nitrate fertilizer, producers are asking themselves what they can do to offset the rising price of forage production.

This is the topic of an upcoming lecture, "Pasture and Hay Production," sponsored by the Colorado State University Extension. Bill Ekstrom, CSU Extension agent, will present the program at 5:30 p.m. March 26 at the CSU Extension Office, 539 Barclay St. The lecture also will be presented at 7 p.m. March 31 at the Rio Blanco County CSU Extension Office.

The lecture costs $15. Ekstrom said people do not have to pre-register for the lecture.

"In livestock budgets, forage production for winter feeding typically accounts for 40 percent of the cost of production and analyses of production records often reveal it to be even higher," Ekstrom said. "Reducing the cost is a pivotal factor in livestock production."

Ekstrom added that producers have faced prolonged drought, high fuel prices and now steadily increasing fertilizer costs. Finding ways to reduce production overhead and maintain production profitability and hay quality is the message of the upcoming forage lecture.

A discussion at the lecture will include the following:

• Are there ways to reduce fertilizer costs?

• What about the different forms of nitrogen? Do they work all the time?

• If unfertilized fields yield about 1.3 to 2 tons of hay per acre, while fertilized fields will produce 3 to 5 tons, how much can I afford to spend? Is it worth spending?

• The quantity and quality of forage produced from grass-dominated mountain meadows can be improved by interseeding legumes. However, the success of this practice often is limited by the strong competitive effects exerted by the existing vegetation. Find out various tricks for successful pasture improvement, including interseeding and aeration.

Fertilization with nitrogen is most economical where weeds have been controlled and additional grass growth is needed for livestock. If additional forage can be purchased or pasture rented at lower cost than fertilizer, these alternatives may be better choices than applying fertilizer.

Soil testing information and testing equipment is available from the Extension Office. For more information, call Ekstrom at 878-9490.

If you notice dense crusts on the bark of your deciduous trees, making the bark appear dark brown, your trees may be infected with the oystershell scale insect. In the Craig area, the aspen, ash, lilac and honeysuckle are among the hardwood plants most commonly attracted by this insect, Ekstrom said.

The oystershell scale is a very small brown or gray-brown insect that attaches to the bark of trees and shrubs, giving the overall appearance of an oyster's shell. Since the insect can kill plant cells as it feeds on sap, branches or sometimes the whole plant can be killed. Oystershell scale also may weaken plants, allowing disease organisms, such as cytospora, to be established.

There are things you can do if your trees are infected. Something you can do right now to help turn the problem around is to scrape as many of the scales off the plant as possible. Use a nylon net "scrubby" or something similar. The scales pop off the plant readily and, once exposed, the eggs dry out rapidly and die.

Late spring, when the temperature is around 50 degrees, horticultural oils can be diluted and sprayed on the trees. The oils have long been a staple for control of many hard or armored scales. They are sprayed with the intention of smothering the insect.

When horticultural oils are applied in the dormant season, before leaves come out, they can be moderately effective against oystershell scale.

According to Ekstrom, things change dramatically when eggs hatch, usually in late May or June. The newly hatched insects are tiny, pale yellow insects known as "crawlers."

During this time, they are highly vulnerable to several insecticides, such as malathion or permethrin. However, these sprays should be applied at or just about the time when the crawlers are active, about a two-week period, on most plants.

Horticultural oils can be sprayed after the crawler period to kill the young stages of scale during June. Be sure to use horticultural oil that allows for foliar or "summer" use and mix carefully to avoid plant injury.

Oils and insecticides can be found at good nursery or farm supply stores, Ekstrom said.

Northwest Colorado residents can call Ekstrom at 878-9490 for more information about oystershell scale insects.

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