Plant Defenses Against Termites

Termites get their nutrition from cellulose. To get the cellulose, termites eat wood. They also eat things that are made from wood, like paper and cardboard. Termites will also eat plant–based fibers like cotton and burlap.

Around the world, termites can be pests of crops. They attack a variety of plants including peanuts and maize. Termites also attack trees that are used for lumber production.

Many trees have developed defenses against termite attack. Some trees do this by developing chemicals like lignin. Subterranean termites avoid wood that is high in lignin. Scientists think that the termites have difficulty digesting it.

Some well–known woods are very high in lignin, including redwood. University tests have shown that redwood, cedar, and several other types of wood were resistant to termite feeding.

The tests also showed that some types of cedar were toxic to termites. Some extracts from redwood were also toxic to the termites that ate them.

Other trees develop resins that are resistant to termites. The resins seem to concentrate in the heartwood. The resins make the heartwood very dense and resistant to termites.

Eucalyptus is one of the woods that are resistant to termite attack. Tallowwood, a member of the eucalyptus genus, is used for construction in Australia because it is resistant to termites.

Scientists have developed wood–treatment products that contain extracts of plants. These products can be brushed onto regular lumber to make it resistant to termite attack.

Tests indicate that some of these products create a barrier that termites will not cross. In some tests, termites would starve rather than go near the wood that was treated with these products. The scientists hope to make these products available for homeowners to use.

In the meantime, homeowners are encouraged to have their homes inspected regularly. Termite control professionals can identify signs of termite activity. They can also point out landscaping or maintenance conditions that might be attractive to termites.