Chemical/Synthetic Termiticides

With enhancement of technology and population explosion, supply and demand of food stood as a challenge to humankind. Eventually, crop protection emerged as a major issue in the arena of agricultural production. Application of more effective remedy to phase out crop loss by insect attack and mitigation of food security could lead humankind towards invention of pest control methods. Use of chemicals in pest management took its place with advancement of agri- chemical techniques. Despite their harmful effect, use of chemical pesticides is an established practice in agriculture. With time and situation, changes have taken place in the use of pesticides, their concentration and sustainable use. Awareness of their dose, limit, application time and hazards borne by them were brought to the notice of people for greater interest to save the earth. In India, Insecticide Act 1968 has specified crop-wise use of chemical pesticides and their use pattern. Similarly, such efforts were seen in many countries abroad. Under leadership of United Nations Environment Program, members of the UNEP/FAO/Global IPM Facility Expert Group on Termite Biology and Management - established in 2000 recommended some chemicals in support of international activities on Persistent Organic Pollutants (POPs), in which as many as seven chemicals were classified as non repellents and eleven chemicals were grouped into repellants (http://www.unep.org/chemicalsandwaste/Portals/9/Pesticides/Alternatives-termite-fulldocument.pdf). Repellants included Bifenthrin, which was found as sodium ion channel inhibitor. Non repellant chemicals included Chlorpyriphos (liquid, granule and RTU forms), Imidacloprid and Fipronil (both in liquid and gel form) as per application site and target population (Table 1). Effective termiticides like endosulfan, lindane etc. are now banned in India.

Table 1: Termiticides in common marketplace

Insecticides approved by Insecticide Act, 1968; Follow Indian Standard Code of practices for anti-termite measures in associated structures, IS 6313 (Part 2): 2013 for pre construction and IS 6313 (Part 3): 2013 for post construction treatment

Descriptions of a few effective termiticides available in common market place in India

Chlorpyriphos
Chlorpyriphos is a less persistent termiticide in the environment and is widely accepted, although it casts more toxicity to vertebrates than chlorinated hydrocarbons. Mode of action of this termiticide is to attack on tye nervous system by binding with acetyl cholinesterase that inhibits its function, causing accumulation of acetylcholine at the available receptor sites. This results into repetitive firing of impulses at the next neural unit.

Fipronil
The mode of action of this termiticide involves blocking the γ-aminobutyric acid (GABA)-gated chloride channel. Mode of action of fipronil is interference with the passage of chloride ions in the nervous system, eventually causing death. According to Henderson (2003), fipronil and imidacloprid are more toxic to insects than to mammals because they can kill insects through hyper-excitation of central nervous system.

Imidacloprid
Mode of action of imidacloprid is on the nervous system of termites by binding to a postsynaptic nicotinic receptor, thus blocking neural transmission. Action of this termiticide prevents transmission of information of the binding sites resulting in a lasting impairment of nervous system eventually leading insect to death. Imidacloprid is a slow acting termiticide and effective even in low concentration. Imidacloprid treatment causes termite becoming sluggish, inhibits grooming and tunneling behavior. Soil type plays key role in effectiveness of this termiticide.

• Pesticides are poisons, so handle them with care. Do not touch or inhale the he contents. While handling the contents use gloves and face mask. Use soap after dealings with insecticides.
• Pesticides packs, containers must be stored in separate rooms, keep them under lock and keys, in rooms or almirah depending upon the quantity stored.
• Rooms or premises meant for store, must be well built, well lit, dry, well ventilated. Keep away the children, pets and domestic animals.
• Disposal of used up containers.

• Resort to chemicals that to only recommended pesticides. Least toxic pesticides are preferred for use depending upon the situations.
• Procure pesticides well before the application date, be concerned about the expiry date and authenticity of the brand and brand claims.
• Read instructions manual of the pesticides and equipments.
• Verify the application equipments, accessories, check that all components are clean, especially filling and suction strainer, spray-tank, cut off device and nozzles.
• A blank spray can be run to ascertain the working of pumps, spraying speed and discharge rates etc.
• Make sure that appropriate protective clothing is available to the workers. The personal protection equipments (PPE) are must for applications.
• Ensure that soap, towel and plenty of water is available.
• Take sufficient pesticides for the day’s application from the store to the application site.

During application

• Never transfer pesticide from the original container and packing into the container.
• Once again read the instructions of pesticides and equipments.
• Follow always the right dose, right method and right timing of application.
• Use appropriate PPE.
• Applicators and other pesticide handlers must use long-sleeved shirts, long pants, shoes plus socks. Use detergent and hot water for washing clothing. Keep and wash PPE separately from other laundry.
• Avoid contamination of the skin especially eyes and mouth.
• Do not apply in high wind, high temperature and rain.
• NEVER drink, smoke or eat when mixing or applying pesticides. Do not blow out the clogged nozzles or hoses with mouth.
• Do not allow kids, domestic animals and other unauthorized persons to be nearby during application, never leave the pesticides unattended in the field.
• Pesticides left over in the tanks after spraying should be emptied and disposed off in pits dug on wastelands away from human dwellings. Never dispose or clean near or to the irrigation canals or ponds.
• After application, equipments must be cleaned properly including the PPE.
• Keep proper pesticide use record.
• Prevent persons from entering treated site until it is safe to do so. Mark the sprayed plots with a red flag or label it as ‘danger’. 

1. Organophosphates (chlorpyriphos) and carbamates degrade at pH >7.0.
2. Impurities/particles clog the nozzles while spraying.