Boise Valley Tree Service - Tree Pest ControlHere in Boise, Idaho and the surrounding valley we are known for lush trees and shrubs. However, no matter how diligently we care for our yards and landscapes, tree pests and diseases can undo hours of hard work leaving our trees looking unhealthy and scarred. Two of the worst offenders are scale insects and aphids
Scale InsectsScale insects are sap-feeding insects named for the scale or shell-like waxy covering that conceals their bodies. There are more than 7,000 species of these tiny sap-sucking insects. In Idaho, most species of shade trees, fruit trees, and ornamental shrubs are subject to scale insect attacks. They are often overlooked or ignored until tree or shrub branches “mysteriously” start to die.
Scale insects can weaken and even kill trees, shrubs and houseplants, but in general, complete loss of the plant is rare. They damage plants by sucking out plant juices. Upon closer examination, these branches are likely to be covered with small bumps that are actually scale insects. Scale insects can be divided into two categories scales that secrete a sugary liquid called honeydew and those that do not.
The “honeydew” can coat buildings, fences, cars, walkways and benches creating a sticky mess. Not only is the honeydew difficult to clean, it can remove and mar paint finishes. |
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The sweet liquid attracts wasps, flies and ants. It can also become food for a black fungus called “sooty mold” due to its color. This mold can suffocate leafs and inhibit the growth of your plants.
Scale insects typically adhere to the stems, branches, and sometimes the leaves of plants to feed on sap, and they have a shell-like bump appearance, which sometimes causes them to be mistaken for a fungal or bacterial disease.
Scale almost always appears in clusters. Unlike other insects, they do not move once they lock themselves into place to pierce the plant and begin feeding on the sap. If you see clusters of tiny shell-like bumps on the stems or leaves of a plant, there is a good chance you are looking at a group of scale. High populations of scale can permanently damage leaves, fruit, twigs, branches and/or tree trunks.
Control measures are most effective during what is called the scale insect's "crawler stage"—the nymphs that appear soon after the eggs hatch. At this point, the nymphs have legs and are actively crawling to find new spots to attach and feed. This is the time when they can be effectively killed with pesticides. However, timing is everything and there is a very short window of opportunity.
Aphids
Aphids are very common soft bodied, sap-sucking insects that can weaken a tree, distort new growth. They also produce a “honeydew” that attracts ants, wasps and other pests. Another problem with aphids is that when the honeydew drops from these insects it attracts a type of fungus called sooty mold.
Sooty mold can grow on honeydew deposits, accumulating on the leaves and branches of your plant and turning them an ugly black color. Not only does this mold discolor the plants and somewhat slow the normal plant processes, sooty mold on buds can kill the young growth damaging the health of your trees.
Some aphids transmit plant viruses which can be a problem on strawberries, raspberries, tomatoes, cucumbers, dahlia, tulips, sweet peas and many other plants.
Aphids can appear white, green, yellow, black, brown and red, depending on their stage of life and where you live. Aphids pierce tree, plant and shrub leaves with their sucking mouth-parts and feed on the juices inside. They usually occur in colonies located mainly on the undersides of stems and leaves. A plant's leaves can turn yellow and/or wilt due to the excessive stress and leaf damage.
Sooty mold can grow on honeydew deposits, accumulating on the leaves and branches of your plant and turning them an ugly black color. Not only does this mold discolor the plants and somewhat slow the normal plant processes, sooty mold on buds can kill the young growth damaging the health of your trees.
Some aphids transmit plant viruses which can be a problem on strawberries, raspberries, tomatoes, cucumbers, dahlia, tulips, sweet peas and many other plants.
Aphids can appear white, green, yellow, black, brown and red, depending on their stage of life and where you live. Aphids pierce tree, plant and shrub leaves with their sucking mouth-parts and feed on the juices inside. They usually occur in colonies located mainly on the undersides of stems and leaves. A plant's leaves can turn yellow and/or wilt due to the excessive stress and leaf damage.
Your plant can become infested when winged “colonizer” aphids land on the plant and lay eggs. Although you may not see the winged version of an aphid actually eating your plant, they are still dangerous because they can lay eggs and start a new aphid colony. Winged aphids are sometimes called “blackfly” or “greenfly” bugs depending on the color (because they are often black or green/yellow, and they look like tiny flies).
Because of their quick reproduction, a few winged aphid “colonizers” can lead to hundreds or even thousands of aphids on a plant in just a few generations. A full-blown aphid infestation can get out of control in just a few weeks.
You may see the following symptoms:
Because of their quick reproduction, a few winged aphid “colonizers” can lead to hundreds or even thousands of aphids on a plant in just a few generations. A full-blown aphid infestation can get out of control in just a few weeks.
You may see the following symptoms:
- It is usually possible to see aphid infestations with the naked eye, and they tend to colonize shoot tips, flower buds and the underside of younger leaves
- Aphids can cause stunted growth with curled or distorted leaves and can weaken the plant
- Many aphids excrete a sticky honeydew which on which black sooty molds can grow
- White cast skins of aphids can accumulate on the upper surface of leaves