Trunk or Branch Invading Insects

Insects which attack trunks, branches, and stems can be particularly damaging, especially the type which bore through stems, eating plants from the inside out. Others may simply attach themselves to the side of a tree and simply suck out the juices in the manner of a sap-sucking insect.

The Cicada actually falls into several categories of garden pests as it attacks trees all through its life cycle. As an adult it will attack to the side of the tree and suck the sap through the trunk. As a nymph it burrows under the ground and attaches itself to the root system and feeds from this relatively protected position. Cicada nymphs are known to stay underground for as long as seventeen years. As an adult it can be seen on the sides of trees making a strange rhythmic buzzing sound. They range up to as long as three inches. When they molt, their empty shells continue to cling to the trunk. One defense against cicadas is to place 1/4 inch netting around vulnerable plants. They are a tough insect and relatively hard to kill with chemical sprays.

Treehoppers lay their eggs inside woody stems, which causes scars along with split and broken twigs. There are over 3000 species of treehoppers. Although not usually terribly destructive, they can stunt fruit trees. The treehopper is closely related to the cicada. They have an unusual shape that is due to a raised area above the thorax. They can be controlled with insecticidal soap (which can be found in organic forms).


The Cutworm is the caterpillar of a moth. It is white or gray and feeds at the ground level on the roots of plants. They get to be from 1 - 1 1/4 inches (2-4 cm). In gardens they can be hand-picked or seedling can be protected by placing a paper collar around the stem.

The various borers get inside branches and eat the pulp generally staying away from the bark. They weaken the structure of the plant by cutting off fluid movement between the roots and other parts of plants.

Clear Winged Moth and Larvae

The Squash Vine Borer is the larva of the clear winged moth. As its name indicates, it attacks the vines of squash plants. Timing plantings and directly cutting out borers are the best organic means of control. Once the borers have gotten into the vines they are difficult to stop.

The larva of the squash borer, Melitta curcurbitae is a one-inch white caterpillar often found in the stem of squash or pumpkin plants. The squash borer moth resembles a wasp. It often has an orange body, metallic green forward wings and clear rear wings. It attacks squash stems often killing a portion of the vine. These problem insects can be cut out of the vine and the damaged portion buried. This will sometimes preserve a portion of the plant. The flying adult moths can be trapped by placing water in a yellow pail or bowl. The insect is attracted to yellow and will land in the water and be unable to free itself.

The Flatheaded borer is a one-inch white larva of various beetles that will attack apple, poplar, locust, and other trees. As they like to strike at vulnerable plants, the best defense is to keep trees healthy and well-cared for.

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