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alternatives to pesticides -bugs/pests - Scale


Actual size: Adult female 1/100” – 1/10”

There are many varieties of scale, which suck plant sap, weakening plants and causing leaves to yellow and drop. Some excrete large quantities of honeydew. There are two to four larval stages. The first looks like a mite, and subsequent stages look like smaller versions of the adult females.  Adult females look like hard or soft bumps on stems, leaves and fruit. Males, minute flying insects with yellow wings, do not feed.

Physical control
Alcohol - For small infestations, hand picking or dabbing scale with rubbing alcohol is effective.
Prune - Prune and dispose of infested branches and twigs.

Biological control
Predators - Encourage predators such as aphid lions (green lacewing larvae), syrphid fly larvae, ladybugs (adults and larvae) and parasitic wasps.

Least-toxic chemical control
Dormant Oils - 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. Apply dormant oil spray only in the winter, or it may defoliate your plant.
Horticultural Oils - Horticultural oils are also called summer oils; these are more highly refined than dormant oils, making them appropriate for use on leaves during the growing season.  Consult a nursery to locate a suitable product and follow all precautions. Don’t use horticultural oils when plants are flowering. Spray in early summer on the crawler stage.
Insecticidal Soap - 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. They are contact insecticides, meaning you must wet the pest for them to be effective. As always, follow package directions and cautions when using these products.



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