Termites primarily feed on wood, but some species collect green grasses and seeds and store these in their granaries inside their nest as food reserves. They are sporadic pests, and locally are important on a wide range of crops.
Some termites eat into the taproots of young plants (e.g. cotton and groundnut) immediately below the soil surface, destroying the central root portions, and fill the resulting cavities with soil. Damaged plants wilt and may die within a few days particularly under drought conditions. Some termites also attack the roots of maize and sorghum, and the damaged plants topple. Termites may also travel up through the roots into the trunk and branches. They eventually disrupt the movement of nutrients and water through the vascular system resulting in death of the plant.
|Soil-covered tunnels built by termites on a mango tree.|
(c) A. M. Varela, icipe
Bark-eating termites attack a wide range of crops and occasionally are locally important pests. They cover the tree trunks or plant stems with tunnels built of soil, plant fragments and saliva and gnaw away the bark underneath these tunnels. Some damage is done underground to the roots and underground stem of the plant. The collected plant material is taken back to the nests for construction of fungal gardens.
Tunnelling damage may kill seedlings or ring-bark trees when large cavities are eaten out of the trees. However, they do not cause damage when feeding on the dead bark of established trees. Sometimes root damage may be serious. Some termites gain access through the dead ends of pruned branch stumps, from which they may invade the living tissues.
The sugarcane termite (Pseudacanthotermes militaris) causes poor germination of sugarcane setts, and when it attacks mature cane, the can is encrusted with earthen tunnels and stalks are often felled when nearing maturity. This termite is a major pest of sugarcane in East Africa. Other species of termites can also cause considerable damage to sugarcane; under severe attack no shoots can be formed and large gaps are left in the field.
|Harvester termite carrying a piece of plant material to the nest.|
(c) B. Loehr. icipe
Harvester termites cut and gather pieces of grass and wood, leaf and herbaceous twigs and carry them to the mounds. They have small earth mounds (about 10 cm) scattered through areas with short grasses. They are major pests of grasslands, and occasional pests of cotton, wheat and groundnuts.
Several species of dry wood and subterranean termites are storage pests and can become a problem in farmers' granaries or in village stores. Most of the damage occurs in wooden storage structures, but some subterranean termites also feed directly on the stored grain. Direct grain losses due to termite feeding are generally low, but contamination with moulds, as a consequence of their attack, is frequent.
Hosts include: Cotton, maize, wheat, sugarcane, upland rice, potatoes, sweet potatoes, groundnuts, soybean, coffee, cassava, tea, cocoa, rubber, oil palm, coconut, some vegetables, some fruit trees like; mango, papaya, citrus, etc.
The first signs of termite attacking roots on seedlings or older plants is wilting. Eventually some plants die or fall over. Pulling out the affected plants and examining the roots and lower stem for live termites and tunnelling will confirm the presence of termites. Plant roots and stems may be completely hollowed out and soil-filled.
Often plants in the field are covered with soil runways or soil sheeting, under which termites may be found. It is important to examine plants in the early morning or late evening, as termites may have moved deeper into the soil during the day when temperatures are high.
Termite attack on trees and bushes often begins in an area of dead wood produced by pruning or other damage. Small cracks or tunnels made by other insects such as wood-boring beetles may allow winged termites (reproductive stage) to enter. Termites may also travel up through the roots into the trunk and branches. They eventually disrupt the movement of nutrients and water through the vascular system, resulting in death of the plant.
Galleries in the wooden parts of the construction reveal the presence of drywood termites in granaries. As termites avoid the surfaces of attacked wood, their presence may only be detected after substantial damage has occurred. Subterranean termites construct visible galleries that are used as runways.
|Termite damage on mango tree bark.|
(c) A. M. Varela, icipe
Affected plant stages
Flowering stage, fruiting stage, post-harvest, seedling stage and vegetative growing stage.
Affected plant parts
Leaves, roots, stems and whole plant.
Biology and Ecology of Termites