Methods of Termite Control in Nigeria
Termites cause the most serious damage when compared with other wood-feeding insects. They attack timber and wood products as well as growing trees, leather, wool and agricultural crops. Man-made materials such as polythene, plastics, some metal foils, as well as books, furniture, wooden electric/ telephone poles and railway sleepers, are equally severely attacked by termites.
Effects of these damages are enormous and call for a systematic control of these termites.
Termite Control on the Farm
Good Agricultural Practices/ Farm Hygiene
Observations made on Cocoa farms in two locations in Ghana some years back, revealed that various species of termites were causing serious damages to Cocoa farms under poor hygienic conditions in Amanokrom (near Aburi), while they cause insignificant damages to the Cocoa farm estates of the Cocoa Research Institute at Tafo. This is because of the comparatively better hygienic conditions maintained at Tafo. Therefore farm hygiene plays a crucial role in reducing termite damage to crops and other woody materials.
Attacks on crops may also be reduced by close spacing of crops, especially Cotton seedlings, while growing different varieties of crops may equally be effective in reducing termite attacks. A number of farmers utilize well composted materials during planting to curtail the activities of termites.
The usual and most common control methods utilize by farmers involve the destruction of mounds to remove the primary reproductive. It is assumed that the elimination of such castes terminates the life of the colony. This method is laborious and ineffective, because the supplementary/replacement reproductives are common in such ground dwelling termites, and they immediately take over the work of the removed reproductives.
Other control methods used by farmers in Nigeria include, burying broken pieces of used torchlight batteries, dead animals, viscera of raw fish, in the soil to serve as barriers against termite invasion. Seed pieces cut from stored yams are bathed with palm oil, to prevent fungal attacks. However some farmers have reported that this also protects the growing yams against termite attacks. Termites are known to be attracted to infestation by certain fungi.
Baiting
Baiting is well suited to social insects because of their foraging, food exchange and grooming habits. However, not until recently that the comparative advantage of baiting is being fully utilized for the control of termites. The long lasting effectiveness of termiticidal soil insecticides and wood preservatives seemed adequate to protect wood used by man. Therefore, the need for new termite control methods was not apparent. However, the concern about the human and environmental hazards of persistent pesticides created doubts about the continued availability of long lasting chemicals for termite control. Coinciding with such doubts was the report that subterranean termites were strongly attracted to wood infested with brown rot fungus, Geophyllum trabeum. This stimulated development of termiticidal baits as new termite control method. This aims at attracting the termites to a reservoir of insecticides (e.g. Dieldrin or Aldrin, or Ch;ordane in corrugated fibre boards), with the aid of G. trabeum in decayed wood. The slow acting stomach poison, Mirex seemed a better choice for the bait insecticide because it will allow time to for the foragers to transport the insecticide to the nest for distribution to other members of the colony.
Chemical control on the Farms
Three chemical control methods may be employed on the farm:
- Direct attack on the termite colonies
- General application of insecticides to the soil before planting
- Local application to the individual plants
Direct Attack Method: To destroy a termite colony, make three holes on top of a large termite mound (90cm high and over) and pour in 27.3 litres of water containing 71ml. of Aldrin or Aldrin emulsifiable concentrate (9.1 litres per hole). Smaller mounds (less than 90cm high) can be poisoned effectively using 4.5 litres of the same dilution per hole. Direct attack method may only apply to and effective against mound-build termites.
General Application Method: General application of insecticides has the advantage of well proven effectiveness, having been successfully used in many parts of the Country. A mixture of 250ml. of dieldrin (Dieldrex 20) or aldrin is prepared with 68.2 litres of water, and 4.5 litres of this mixture can be sprayed over 33 sq.m. of soil. This method is effective against both mound-building and underground termites.
Local application Method: This method is expected to form a protective barrier around each plant, and prevents the possibility of long term adverse effects on the soil. It also has the advantage of saving costs, as much less quantity of insecticide is required. This is carried out by dipping seed pieces of the material to be protected (yam, Cassava, Sugarcane etc) in approximately 0.1% suspension of aldrin or dieldrin wettable powders before planting. In another vein, termite attack may occur on yam tubers, for example, at a latter stage. In this case, treatment of the storage heap may be required. On a heap, approximately 90cm. in diameter at the base, 56.7ml. of 2.5% of aldrin or dieldrin dust should be incorporated into the heap in several layers as it is built up.
Some quantities of insecticide may be applied to planting holes before tree crops are planted.
Other local applications include pot treatment of seedlings. Dieldrex 20 emulsion can be applied through the watering system of the nursery in four doses at monthly intervals. For better results, pre-treatment of potting soil with 2% dieldrin dust formulation is recommended at doses of 141.8-283.5ml. per cubic meter of potting soil.
TERMTE CONTROL IN BUILDINGS
In the tropics where termite attack on buildings are rampant, foundation trenches dug on building sites are sprayed with 2 measures (56.8ml.) of aldrin or dieldrin or dieldrex 20 mixed with 4.5 litres of water. This is sprayed in every 60cm of trench, which should be back-filled and sprayed again. The treatment can protect buildings against termite attack for several years.
For erected buildings, it is recommended that 4.5 litres of the above dilution of aldrin or dieldrin should be sprayed into a narrow trench dug around the outside of the building, using 4.5 litres of the chemical to every 60cm of trench. The trench should be back-filled and sprayed again. The trench should not be made deeper than the base of the foundation wall. Floors may also be lifted and sprayed using this recommended dosage to every 0.5 sq.m. Alternatively, holes may be made onto floors and walls of buildings (where hollow blocks are used), and application of diluted dieldrin made through the holes. Planks and other wood materials should be treated with diluted dieldrin before use to protect them against termite attack.
The soil can also be treated prior to laying of the building foundation, with 16.2 to 32.5 litres per 9.0 sq.m. of 5% Pentachlorophenol (PCP) in fuel oil or water emulsion. Alternatively, the soil may be treated with 45.5 litres per 9 sq.m. of 3% dieldrin. When mixing concrete, it is suggested that a 0.5% emulsion of dieldrin (1.14kg of dieldrex 20 in 45.5 litres of water) be used as the mixing water. It is also recommended that the building sites be leveled and treated prior to casting of slab floors. The under listed chemicals preparations are effective and may be applied at the following rates: Copper Naphthanate (5% in fuel oil at 2-4 litres/sq.m.), Sodium Pentachlorophenate (2.5% in water at 6-10 litres/sq.m.), Benzene hexachloride (0.8% in fuel oil or emulsion in water at 6-10 litres/sq.m.).
About the Author
Dr. Bolarinwa Olugbemi is an Entomolpgist, specialising in the ecology and behavior of Termites. His secondary area of interest is the development of Nigerian Raw Materials as inputs for the local industries. Poverty reduction as well as building capacity for small scale industries are also of interest.
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