HOW TO IDENTIFY IF YOUR HOMES ARE INFESTED WITH ASIAN SUBTERRANEAN TERMITES (AST)
Asian Subterranean Termite (AST), scientifically known as Coptotermes gestroi, is an intelligent insect pest which tunnels its way through the soil to its food source. The preferred feeding materials include items containing cellulose – an important structural component of the primary cell wall of green plants. This makes living plants, especially trees, dead wood and more importantly wooden structures their perfect target. AST is exotic to Fiji and has caused massive damages to houses, schools and vegetation in the Lautoka and Labasa areas amounting to millions of dollars. The Biosecurity Authority of Fiji (BAF) under its Termite Project is working strenuously to contain, control and manage AST in these areas. AST, the second most destructive subterranean termite species in the world, live approximately 6 – 18 feet underground making it almost impossible to detect them unless signs of their presence are found on trees and building structures. This article provides information on some of the ways to identify AST should you suspect incursion in your homes and the ways to minimize its spread. Where to inspect your homes for AST Carefully check: Any wood construction in basement and crawl space. All sills, sub floors, joists, support posts, supporting piers, basement window frames, wood under porches. Places where concrete steps, porches or slabs join the wooden structure. All the hollow blocks, cracks in cement or brick construction and expansion joints. Any scrap wood on the exterior, old tree stumps, fence posts and exterior frames of basement windows. What to look for The following list indicates common signs of AST infestation: The presence of mud-like material (earthen tunnels) that line AST galleries in an irregular pattern. This mud-like material is a mixture of soil, feaces and saliva. The presence of mud-like material around gaps in timber or where concrete slabs meet timber. Buckling paint on wooden structures. A ‘crushed’ appearance of timber and/or boards at structural bearing points. A dull thud (hollow sound) when termite damaged wood is tapped. If you pick a piece of wood and suspect it to be infested with AST, probe the surface of wood with a pen knife. If you find tunnels running parallel to the wood’s grain, the wood and the place where you picked the wood from is most likely infested with AST. Please do not move these types of wood and contact BAF immediately. When in doubt, it is recommended that you have your house thoroughly inspected by the BAF Termites team who are trained to detect the sometimes subtle signs of termites. What do the mud-tunnels indicate Asian Subterranean Termites (AST) keep their main colony in the ground and build “mud tubes”, the thickness of which is around the diameter of a pencil that connect the nest (maintained in an environment with moisture) to the food source (wood). The tunnels may contain broken mud particles with feacal materials. These mud tubes or shelter tubes are proof of termite infestation, but their absence does not necessarily mean that a structure is free of termites. AST may reach sills and other wooden structures through cracks or voids in the foundation wall, under the outside stucco or from earthfilled porches, steps, terraces and patios. You can break open tubes to determine if termites are still active inside. AST often rebuild damaged tubes and this is an indication of continued activity. Old tubes are dry and will crumble easily. What we know from AST feeding pattern Since AST build their nests underground, damaged wood that are eaten by AST usually have an accumulation of soil or mud within the tunnels. AST only eat softwood, and because of this damaged wood will appear to be layered – the result of the workers not eating the hardwood portion. In addition, AST feed “along the grain” rather than across the grain creating a ripple-like pattern inside the wood. Swarming Period (August to November) A “swarm” of what you would call “flying ants” especially near light sources may be that of AST. This also indicates a nest may be nearby. A swarm is a group of adult male and female termites that are capable of reproducing and leave their nest to establish a new colony. Swarming occurs when a colony reaches a certain size and is most common during the months of August to November. Most swarmers emerge during the day, more frequently on warm days after rain. Swarmers found outdoors, for example near tree stumps, indicate that your house may not be infested; rather AST is present on the outside only. On the other hand, finding swarmers indoors often means that you have a termite infestation within your house. At first glance, swarmers and ants look similar, but can be distinguished How to reduce the risks of AST infestation - The DOs and DON’Ts It is wise to have your house inspected for AST at least annually by Biosecurity officers. More frequent inspections may be required in high risk areas, that is, hotspot locations of Lautoka and Labasa and areas where there are a great number of trees or virgin bush nearby. Some common practices which may increase the risk of AST infestation include: Placing turf, paving, concrete paths, bark and garden beds against the house wall Leaving loose timber stacked up or leaning against the house Movement of infested propagating material such as cane stalk and cassava stalk for planting to new sites or selling to the neighboring districts that do not have AST Dealing with termites - Who to contact and what to do Do not disturb the nest Immediately arrange for Biosecurity officers to conduct a thorough inspection inform your neighbors because one termite colony can affect several homes Take action to eradicate the termites! Disposing of Termite Infested Wood and Debris Wood should not be buried. Even pesticide treatments will not prevent buried wood from eventually becoming infested with AST. Downed trees and large shrubs on the ground should be cut into movable segments. by certain physical features. The shed wings of swarmers indicate termites have entered their next phase of development. All timber, boards, wooden material and cut trees should be disposed by burning. Contact BAF on the best practices to dispose AST infested material. Remember, it is illegal to move any termite host material from the declared termite infested zones. Help the Biosecurity Authority of Fiji control and contain the spread of AST.