Roses are America's favorite flower. They also are the favorite attraction of just about every pest known to man.

The worst insect pests are Japanese beetles and aphids.

Japanese beetles are no strangers to gardeners. They not only damage roses but many other plants. The ½-inch long, metallic green insects devour flowers and skeletonize leaves from early July to late August in our area. After feeding on the plant, they mate and lay eggs in grassy areas. The grubs of the beetles feed on grass roots for a year and then emerge as adult beetles.

The beetles often eat the entire flower. Affected buds often fail to open or are deformed when they do open. The leaves may be notched or riddled with holes.

Controls for Japanese beetles are hand picking them in the cool of the evening or early morning when they are especially slow. Chemical controls are Orthene and Sevin. Eliminating the grubs in your lawn may be helpful, but the adult beetle can fly for up to ½-mile and does not honor property lines. If your neighbors' yards have not been grub-proofed, you will need to resort to hand picking or chemical control.

Aphids (also called plant lice) are

-inch green or pink soft-bodied insects. They damage roses by sucking the juice from the rose stems and buds. This causes the buds to be deformed and to fail to open properly.

Aphids do not require males to reproduce. A female gives birth to over 100 in her short life. In summer weather, aphids can mature in five days.

A natural control is ladybugs. Insecticidal soap is an organic control, but it must come in direct contact with the insect. Isotex is a good chemical control.

The most common and troublesome diseases are black spots and powdery mildew.

The black spot fungus infection occurs when the fungus grows through the cuticle of the leaf and enters the lead cells. The surface of the leaf must remain wet for at least six hours for the infection to occur. Once black spots show on the leaves, new spores can be produced in as little as 10 days. Rain and overhead watering can then spread the disease to other leaves.

The principle deterrent to black spot disease is good housekeeping. Be certain to remove all fallen leaves in the fall and all infected leaves and dead plant material during the growing season.

Two fungicides labeled for black spots are Daconil 2787 and Mancozeb. These should be applied in 7- or 10-day intervals. A homemade remedy recommended by organic gardeners is 1 ounce of baking soda and 4 ounces of Murphy's Oil Soap mixed in with 1 gallon of warm water. Apply in 7- or 10-day intervals making sure to wet all leaf surfaces.

Powdery mildew typically grows over the top surface of leaves. Mildew grows best under cool, moist conditions. In our area, mildew makes its appearance in late summer when the nights begin to cool. Mildew infection begins with slight curling of the leaves. When growing on the leaves, it looks like a coating of chalk. As the infection worsens, the leaves turn reddish, then black before falling off the plant. The infection can induce bud drop and distorted blossoms.

The same controls used for black spot are also effective for use on mildew. High nitrogen fertilizers should be avoided as they can increase the problem.

Pete Hale of Sarver is a Master Gardener with the Penn State Master Gardener program.