Soft-bodied insects from 1⁄16 to ¼ inch long, aphids can be found in a range of colors from black to pink to white and pale green. They usually cluster on the new growth of perennials, roses, and woody plants. Adults and nymphs damage plants by sucking out sap. In small numbers, aphids do little harm. But they can rapidly build up to destructive numbers.

Commercial product: Insecticidal soap spray (such as Safer), or horticultural oil
Home remedy: Homemade soap spray (add ½ teaspoon mild dish soap and 1 teaspoon cooking oil to a 1-quart sprayer filled with water)

Gentle pest controls

These tiny, eight-legged pests of black, green, red, or yellow are nearly invisible. They destroy plants by sucking juices from the leaves, giving the leaves a stippled, bleached, or spotted appearance. Mites are most severe in hot, dry weather.

Commercial product: Insecticidal soap spray (such as Safer), or horticultural oil
Home remedy: Homemade soap spray (add ½ teaspoon mild dish soap and 1 teaspoon cooking oil to a 1-quart sprayer filled with water)

Gentle pest controls

Scales appear as clusters of crusty, waxy, or smooth bumps on leaves, branches, and the bark of trees and shrubs. There are numerous types varying in size, color, and shape. They spend most of their lives immobile, sucking nutrients out of their plant victims. Black sooty mold fungus may cover parts of the plant; heavily infested twigs and branches may die. Scales have protective coatings that help prevent sprays from affecting them; young crawlers are most susceptible to sprays.

Commercial product: Insecticidal soap spray (such as Safer), or horticultural oil
Home remedy: Homemade soap spray (add ½ teaspoon mild dish soap and 1 teaspoon cooking oil to a 1-quart sprayer filled with water)

Gentle pest controls

These tiny, winged insects appear in large numbers, typically on the undersides of leaves; vegetables and ornamental plants are favorites. Both the adults and wingless, transparent nymphs suck sap from plants. Affected leaves may be stippled yellow and covered by black sooty mold fungus. When the infested plants are disturbed (by humans, pets, or the elements), whiteflies scatter.

Commercial product: Insecticidal soap spray (such as Safer), or horticultural oil
Home remedy: Homemade soap spray (add ½ teaspoon mild dish soap and 1 teaspoon cooking oil to a 1-quart sprayer filled with water)

Gentle pest controls

Slugs and snails are mollusks, not insects. Snails have brown shells; slugs do not. Slugs come in many colors and sizes, but the 1-inch-long brown garden slugs are the most common pest of plants. Both snails and slugs rasp large, ragged holes in leaves and flowers.

Commercial product: Iron phosphate (Sluggo, Escar-Go!, Worry Free Slug and Snail), copper barrier
Home remedy: Handpick at night. Apply coarse sand.

Gentle pest controls

These small six-legged insects live in colonies in the soil, under rocks, or in crevices between paving stones. Newly hatched ants have wings; adults can be distinguished from termites by their narrow midsections. Ants encourage and protect sap-sucking insects such as aphids and scales.

Commercial product: Citrus spray (Orange Guard, Bugs 'R' Gone), boric acid baits, sticky barrier (Tanglefoot)
Home remedy: Caulk entry cracks. Wipe up trails with soap and water

Gentle pest controls

These white or gray fungi attack the foliage and flowers of many kinds of plants, turning infected leaves yellowish green to brown, and stunting and distorting new growth. Mildews thrive when cool nights are followed by warm days--particularly in fall.

Commercial product: Lime sulfur (calcium polysulfide); effective against powdery mildews and rusts
Home remedy: Baking soda spray (mix 1 teaspoon baking soda and 1 teaspoon horticultural oil in 1 gallon of water); effective against blackspot and powdery mildews

Gentle pest controls

Blackspot, fringed black spots on leaves, is a fungus disease that can defoliate a plant. Rusts are orange-yellow to rusty brown fungi that attack many plants. Powdery pustules appear on the undersides of leaves, but the first sign of infestation may be a yellow mottling on the upper leaf surfaces.

Commercial product: Lime sulfur (calcium polysulfide); effective against powdery mildews and rusts
Home remedy: Baking soda spray (mix 1 teaspoon baking soda and 1 teaspoon horticultural oil in 1 gallon of water); effective against blackspot and powdery mildews

Gentle pest controls