- Sticky liquid (honeydew)
- Black sooty mold on leaves and stems
- Small, pear-shape, tubes on abdomen
Aphids can curl leaves, distort plant growth, and reduce the production of flower buds. They produce a sticky liquid excrement called honeydew that is deposited on leaves and flowers. This secretion sticks leaves and flower petals together or turns leaves black when colonized by a fungus called sooty mold. Some aphids just excrete honeydew and others excrete honeydew and wax. Aphids are generally pear-shaped insects, with two visible bumps on the hind end. Most species have winged and wingless forms. When present, wings are clear and held roof-like over their body when the insect is at rest.
Aphids get into the flower garden by flying from their overwintering host, or when infested plants are brought in from a greenhouse. Aphids can reproduce wingless offspring without mating for a few weeks while plants are actively producing new twigs and leaves. As plant growth slows and food becomes exhausted, aphid females produce winged offspring that fly to more vigorously growing annual and perennial flowers, vegetables, and agronomic crops. Aphids damage plants when large numbers are present, coating them with sticky honeydew excrement, or black sooty mold. Although aphids can transmit serious diseases to commercial flower, vegetable, and fruit producers, it is not common in home gardens.
In most cases, aphids are only temporary cosmetic problems in ornamental home landscapes. In time, the native predators and parasites of aphids usually take care of most problems. Control is needed when plants become heavily distorted, or if excessive honeydew production creates a sticky mess that attracts stinging insects and makes plants unsightly. Keep plants well-watered and properly fertilized. Overfertilization can prolong aphid infestation by stimulating shoot growth. Application of insecticidal soaps or summer oils, or neem products containing azadirachtin, can kill large numbers of aphids while sparing many natural enemies. Neem is systemic and can penetrate tight leaf buds where aphids can feed. Broad-spectrum contact insecticides like bifenthrin can kill more aphids, but may foster outbreaks of spider mites later in the season.
Active Ingredients include: Abamectin, Acetamiprid, Azadirachtin, Bifenthrin, Deltamethrin, Fluvalinate, Horticultural oil (Paraffinic or superior oil) , Insecticidal soap (Potassium salt of fatty acid), Lambda- cyhalothrin, Neem oil, Permethrin, Pyrethrin, Resmethrin
