Organic Ways to Kill What Is Eating Petunias

Insecticidal soap spray is a relatively safe way to kill soft-bodied, sucking insects such as aphids, mites and thrips. Although you can mix the spray at home with liquid dishsoap and water, commercial products are purer, milder and less likely to damage the foliage. Use insecticidal soap only when necessary and limit its use to infested plants because the substance kills any insect -- good or bad -- that comes in contact with the soap. However, insecticidal soap is considerably safer than pesticides because it has no residual, lingering effect and doesn`t drift in the wind.

Video: How to Make a simple Organic Insecticide Spray (Aphids, Blackfly, Whitefly etc)

Caterpillars, which look like plump worms, are moths and butterflies in the larval stage. Although moths and butterflies land on flowers only long enough to pollinate the plants or drink the water and nectar, caterpillars can strip a petunia to the ground rapidly. Hand-picking the pests is the safest and most effective means of control. However, Bacillus thuringiensis, a natural bacteria, is an effective treatment for young caterpillars. The bacteria kills the caterpillars, usually within 48 hours, but doesn`t harm honeybees or beneficial insects that prey on petunia pests. The bacteria, also known as Bt, is also considered environmentally safe.

Video: How to Kill Aphids on Indoor Plants EASY in Minutes!

Slugs cause considerable harm to petunias when they chew jagged holes in the leaves. Like caterpillars, hand-picking is a safe and effective means of control. Eliminate slug hiding places as much as possible by keeping the area around the plant neat and free of debris. Similarly, limit use of mulch to 3 inches or less. A number of noninvasive treatments are worth trying. For example, make traps by laying boards or grapefruit halves around the petunias. Lift the traps every morning and dispose of slugs hiding underneath. You can also surround petunias with a gritty barrier such as coffee grounds, sandpaper, sharp sand, wood ash or other sharp substances that lacerate slugs` slimy skin.

Healthy petunias are more resistant to pests than weak, stressed plants. Water petunias only when the soil feels dry because waterlogged soil creates conditions ripe for pests and disease. Clip and dispose of wilted blooms and dead, dry leaves to keep the plant neat and tidy. Fertilize petunias every two weeks, using a dilute mixture of an all-purpose, water-soluble fertilizer. Mix the fertilizer at a rate of 1 tablespoon in 1 gallon of water.