Scale insects are causing a lot of problems this spring on trees, especially oaks. There are many kinds of soft scale bugs that infest woody ornamental plants. They appear as crusty bumps on the bark, but you might not notice them because they are often close to the color of the bark.

Like their relatives the mealybugs, scales secrete large quantities of undigested sap, called honeydew. And when you have honeydew, you always have the parasitic fungus sooty mold.

Any scale insects you see now on trees are probably dead females, but there is likely a mass of eggs underneath their shells. If the eggs hatch, the young crawlers will move from their protected sites to find suitable places to feed.

The good news is that they lack a protective exoskeleton at this stage, so they are vulnerable to treatment with insecticides. One of the most effective ways to kill scale is to spray them with a dormant oil. Avoid spraying on a hot day, though.

Another effective insecticide is acephate, commonly sold as Ortho Systemic Insect Spray, which the plant absorbs. It lasts for about six weeks.

The third option is Bayer Advanced Tree and Shrub Insect Control. It contains imidacloprid and is mixed with water and poured on the ground over the plant's root system. This treatment will be effective for a year and is an effective control method for a large tree that cannot be sprayed.

Climbing roses

The old saying is that "the secret to having good climbing roses is prune, prune, prune," and it's true.

Now is the time to get out the pruning shears, just after they bloom.

Climbing roses require special pruning for profuse flowering. In the spring, when many varieties produce most of their flowers, new canes will develop that will carry next year's flowers.

Prune to remove the oldest canes near ground level to promote vigorous new shoot development. Also prune climbers to keep them trained to their support, whether it be a fence or trellis. Some climbers continue to bloom through summer, but their peak flowering is early in the season. Cut them after that first flush of flowering.

Canes of most climbers are good flower producers for two years. In some cases, new canes develop only on the older canes, rather than from ground level. In such cases, remove the oldest canes in the early spring, leaving five or six of the healthy, vigorous ones.

You also need to cut all faded flowers.

Climbing forms of many hybrid tea roses are generally more vigorous than their corresponding bush varieties. Those should be pruned in late winter or early spring to remove weak, spindly growth and dead or diseased branches.

Sid Mullis is the director of the University of Georgia Extension Service Office for Richmond County. Call him at (706) 821-2349, or send e-mail to smullis@uga.edu.