They are such oddly shaped and immobile pests that they often resemble shell-like bumps rather than insects. Algae, lichens and moss often form green or grey, powdery or mossy, crusty growths on the stems, branches and trunks of trees and shrubs. Here’s our recommendations: Get a Tree Service to Spray your Trees … SCALE INSECTS are the usual cause of sweet, sticky drippage (honey-dew) from trees that collects on surfaces below. This makes it increasingly difficult for scale control. Heavy infestations may cause leaf yellowing, stunting, severe plant stress, and dieback. In many cases, heavy infestations build up unnoticed before plants begin to show damage. Interestingly, scale varies widely in its effect on plants. The most serious problem they cause is honeydew which is a clear, sticky secretion they leave behind as they feed. Scales in other families include important pests of cactus, elm, oak, sycamore, and various conifers. Other plants succumb before you can even notice the problem. APHIDS are often blamed, and sometimes contribute to the honeydew, but by far the most copious honeydew production is by soft scale insects described below. Over time, an untreated population of magnolia scale may lead to decline of the tree. Spot signs of scale damage. Some scale species lack males and the females reproduce without mating. The scale sucks sap from the tree and causes leaves to turn yellow and drop. While this can worry gardeners, these growths are harmless, although may occasionally indicate a lack of vigour in the affected plant. Scale insects feed on the bark, leaves, and fruit of the host plant and can cause stunting, leaf drop, fruit lesions, and eventually death of branches or entire trees if … Soft scales will do some damage but they rarely do enough damage to kill a plant. Managing White Prunicola Scale is possible, but it requires frequent inspection, periodic tree spraying, and a little extra effort to remove pests. Many trees will have small numbers of scale each year; they need monitoring but probably not treatment. The first symptoms are yellow, falling leaves. Armored scales and soft scales are the most common types (or families). Trees can usually tolerate small populations of scale. Generally, they are divided into two categories, armored (hard) and soft scale. The scales tend to be more numerous on trees that are already under stress from causes … Scale Treatments Scale insects belong to a large group of sucking insects that attack a wide variety of trees and shrubs. It seems to be dependent on the species of scale, rather than the species of plant. Common on backyard trees, ornamental shrubs, greenhouse plants and houseplants, over 1,000 species of scale insects exist in North America. 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