Most Common Pests in Ornamental Plants:
Part of maintaining a healthy landscape is to monitor for insect activity. First of all it should be noted that many insects are either helpful or neutral to a plants ecosystem, so you should not fret at the first sight of insects in or around your trees and shrubs. However, there are some pests that can harm your ornamental plants and being able to identify them is important for knowing how to protect them.
Here are some of the most common insects that affect ornamental plants:
Aphids are a jelly like, soft bodied insect that suck on the nutrients of foliage. A few aphids are not enough to cause too much harm to your ornamental plants but if you find them in large quantities then you should treat the plants with insect control.
The picture above shows tent caterpillars attacking a tree. Caterpillars are some of the most destructive insects to trees and plants. Caterpillars are chewing insects meaning they eat the plants. When monitoring plants, you should look for damage because many caterpillars provide little to no harm to plants. The most common species of caterpillar that cause damage are: tent caterpillars, inchworms, fall web worms, and leaf rollers.
Another chewing insect are beetles which feed on the leaves or the roots of plants. Once again, the odd beetle is not a huge problem but when found in large populations they can be very destructive to your plants. In addition to chewing beetles, there are also boring beetles (round headed borers, flat headed borers and metallic wood borers). Boring insects tunnel through branches and bark and when severe they can cut off a plants food supply.
Thrips are not really chewing or sucking insects, they are actually rasping insects. You can identify them by looking very closely for rasped surfaces or deformed leaves.
In addition to the insects identified above some species of bees, crickets, grasshoppers and wasps can be damaging to ornamental trees and plants. What is very important to note is that any insect found in very small populations is not likely to harm your trees or plants. You only need to be concerned if you see lots of visible damage (foliage loss, discoloration, wilting etc.) or if you see heavy infestations of damaging insects (insects found in large quantities).