Mound forming termites
Scientific name
Termites that attack some rare fruit are from 2 genera (Nasutitermes spp. and Coptotermes spp.) that build earthen mounds.
Description of adult
Termites live in colonies and have 4 castes including workers, soldiers, queens and kings. They are usually identified on the shape of the soldier caste. The adult soldiers of Nasutitermies spp. have bulbous heads drawn out into a long snout at the front. The snout can be used to squirt fluid that is irritating to other animals. Soldiers of Coptotermes spp. possess more normal-shaped heads but have enlarged sickle shaped mandibles (jaws). Soldiers usually have darker and harder exoskeletons (external skeletons) than workers. Workers from both groups are similar in shape to soldiers but have smaller inconspicuous mandibles and normal-shaped heads. Queens and kings are similar to workers in shape except that they also have harder and darker exoskeletons and initially they have wings.
Immature stages
Eggs are usually laid only by the queen and are seldom seen. Nymphs are similar in appearance to workers except for a lighter colour (cream to white), and being smaller.
Life history
The queens and kings fly away in large numbers from the mound, usually on warm days or evenings during periods of high humidity. They pair off and find a place to excavate a new mound. They chew off their wings and the queen starts to lay eggs. In the process and over time she becomes enormous, eventually dwarfing the king. She can move only slowly by peristaltic movements of her body and relies on the king and her progeny for food and protection. She produces eggs continuously throughout the year. The environment inside the mound is kept at a more or less stable humidity and temperature.
Distribution
Termites are found throughout Queensland. However, they prefer drier environments.
Host range
Termites are mainly a problem in crops grown in drier environments such as cashew, mango and citrus.
Damage
Minor and sporadic.
This insect causes damage to cashews and other fruit trees in drier areas. Large numbers of termites will result in the destruction of the interior of the branches. Strong winds or the weight of fruit will cause damaged branches to break. The size of the mounds in an area may not be an indication of the potential problem as in some areas the major portion of the mound is below ground level. The termites may tunnel up the inside of the trunk and branches or build covered runways to reach damage parts of the trunk or branches to gain access.
Control
Not determined. Inspect scaffold branches for mounds and covered runways during pruning.
Cultural
Prior to planting remove and burn old stumps and roots from the field. Neglected trees with dead wood are very susceptible to attack. Remove and destroy dead or injured limbs and paint pruning surfaces with water based paint or a commercially available coating compounds sold specifically for that purpose. Destroy mounds and covered galleries in trees.
Termites are usually not a problem in well-managed crops where reasonable growth is maintained.
Chemical registrations and permits
Check the Australian Pesticides and Veterinary Medicines Authority database for chemicals registered or approved under permit to treat this pest on the target crop in your location. Always read the label and observe withholding periods.