There are about 2,500 species of termites. The insects provide important ecological functions such as aerating soil by clearing organic matter and improving soil fertility through the mineral content of termite mounds, as well as being a food source for many mammals. All termites digest cellulose and often do significant damage to crops, buildings and forests. Termites develop nests underground, above ground in mounds and also directly in wood. Eucalyptus oil and mulch is thought to deter termites, though termites are still a problem in eucalyptus forests.
Eucalyptus mulch often is recommended to deter termites due to the aromatic properties of its oil. It promotes plant growth and is claimed to provide a barrier to termite infestation when placed in lawns and parks, and also around horse stalls and animal quarters. According to a study done at the Structural IPM Program at the University of Maryland, termites that consumed mulch made from eucalyptus, hardwood or pine bark had lower survivorship rates than termites that fed on mulch made from white birch.
Eucalyptus oil is a colorless liquid with a camphor scent that is thought to deter termites and other insects. Eucalyptus oil has been used to kill dust mites and as a mosquito repellent, and also to control the spread of mosquito-borne diseases such as malaria and dengue. Commercial termite control measures such as bait systems, soil treatments and wood treatments are recommended for termite eradication. Using eucalyptus oil on flowers and plants in your garden, however, may help prevent a termite infestation by encouraging termites to search for food sources farther away from your garden and house.
Damage to Eucalyptus Trees
In tropical regions, termites cause significant damage to eucalyptus forests. Bud, root or soil termites attack the buds and roots of eucalyptus trees, causing girdling of buds and destroying the root system. The buds develop calluses from resisting termite attack, which decreases the economic value of the tree. Heartwood termites attack trees 2-years-old or older by hollowing and destroying the inner portion of the tree.
Controlling Crop Damage
Fungus-growing termites begin a cycle of crop damage by feeding on dead organic matter such as crop residues and humus. When termites ingest the fungi, the spores pass through the termite’s digestive tract and germinate in the fecal matter, spreading the fungi to the crops. If dead organic matter is not available, termites will feed directly on live crops such as millet and maize. Harvester termites are found in dry areas, live underground and collect live green grasses and crop seedlings. Eucalyptus oils are known to have potent anti-fungal properties as well as insecticidal properties that may control crop damage.