alternatives to pesticides - bugs/pests-aphids
More than 4,000 species of aphids have been identified. There are black, brown, red, purple, pink, green and yellow aphids. Some have wings and others do not. They all have a soft body about 1/8” long and a soda straw mouth part adapted for extracting plant juices. Because aphids bear live young, their populations grow rapidly. Late in the fall, males are born to fertilize over wintering eggs. These eggs, deposited in plant crevices and garden debris, withstand inclement weather to hatch in the spring. Most aphids excrete a sweet, sticky substance called honeydew as they feed. It serves as food for ants, bees and flies and as a growing medium for sooty mold.
Avoid planting species that attract aphids. These include birch trees, roses and certain vegetable varieties such as brussel sprouts. Consult your local county extension office or nursery for help choosing aphid-resistant plants. Also be sure that plants are healthy and have proper growing conditions. Weak or stressed plants are more susceptible to attack. In the fall, get rid of all garden debris where aphid eggs can over winter, and cultivate the garden soil 6” to 8” deep where possible.
For small infestations, hand pick, and destroy the aphids. On sturdy plants, use a strong spray of water to wash them off. If ants are also present, follow the steps outlined in the “Ants” section.
Biological Control- Aphid Predators
Aphid predators include syrphid flies, green lacewing larvae and ladybugs (also called ladybird beetles). Chalcid and braconid wasps are aphid parasites. Parasite and predator populations often lag behind aphid populations, so there may be periods in the year, particularly in the spring, when the aphids appear to be out of control. Often the predators can catch up and restore control, but be patient. Remember to provide the basics: water, shelter and food. Plants may develop some damage but should outgrow it. If pesticides are applied when predator populations are present, they may be harmed and prevented from keeping aphids in check.
Ladybugs and lacewings can be effective in controlling aphids. They are available from many nurseries. Before introducing any predators, reduce aphid numbers by pinching off severely affected plant parts or hosing off most of the aphids. For best results with ladybugs, choose the right time of year and time of day to release them. Ladybugs are most active when the weather is warm, from April through September. Dusk is the best time of day to release them. Water the foliage where the aphids are feeding. The hungry and thirsty ladybugs will be attracted to the water drenched foliage and find the aphids for food. They do have a tendency to disperse when released. Both the ladybug adult and larvae are predators. Green lacewing larvae are also effective predators of aphids and can be purchased and released.Least Toxic Chemical Controls
Insecticidal soaps are highly refined liquid soaps (technically the potassium salt of fatty acids), sometimes combined with citrus oil. Soaps are normally mixed with water and sprayed onto leaves to control spider mites, aphids, scale insects, whiteflies and other soft-bodied insects. You may need to repeat applications. To make your own, mix one tablespoon Castile or Ivory soap in one gallon of water and spray on infested plant parts. These are contact insecticides, meaning you must wet the pest for them to be effective. It is important to use pure soap only. Detergents can burn plants. Always follow package directions and cautions when using these products.
As a last resort for severe infestations use:
Rotenone is a tropical plant-derived insecticide that is harmful to insects, fish, birds and mammals. Read labels to see if the product is mixed with other pesticides. Check the label to see if the pest problem and the plant you want to protect are listed. It is toxic and should be handled with care. Follow label instructions exactly.
Sabadilla the seeds of this South and Central American plant are ground into a powerful insecticidal dust. It is effective against grasshoppers, codling moth larva, webworm, aphid, cabbage looper, chinch bug and many household pests. It can irritate mucous membranes and cause sneezing. Honeybees are vulnerable to it. Handle it carefully.
Pyrethrum is an effective, short-lived, naturally derived insecticide made from chrysanthemum flowers. It is toxic to all insects, including beneficial ones, and moderately toxic to birds and mammals. It should be the last resort for ornamentals and is not recommended on food crops. Avoid using formulations that contain piperonyl butoxide, which is currently being evaluated for its carcinogenicity. Pyrethrins are the individual chemicals found in pyrethrum. Pyrethroids are a new array of synthetic chemicals, such as cyfluthrin and cypermethrin. They resist breakdown, thus negating their major environmental advantage. With the three names being so similar, they can easily be confused. Pyrethrum is the least hazardous.
Dormant oil spray applied in the winter may smother over wintering aphid eggs, but you may want to wait to take action until the problem reappears. Dormant oils act by coating the plant surface and suffocating any insects that are present. Target pests are aphids, mites, scale insects, whiteflies and eggs of many pests, including some caterpillars. Dormant oils are meant for use on leafless, deciduous plants (especially fruit trees) in the winter to reduce pest populations before they hatch. If used in summer, these oils might defoliate the tree.