Thavasi Peruma mixes neem (Azadirachta indica) oil and kerosene in equal quantities and sprays on the coconut trees to control the black headed caterpillar and Rhinoceros beetle. Some farmers also put plants of kolunchi or Purple tephrosia (Tephrosia purpurea) in the primordial region of coconut trees to prevent attacks by the Rhinoceros beetle. Alternatively farmers also grow karpooravalli (Coleus armaticus), a medicinal and aromatic plant, in the coconut orchard. They believe that the strong odour of this medicinal repels the rhinoceros beetle.
Formulation: Mixture of neem (Azadirachta indica) oil and kerosene in equal quantities; (Tephrosia purpurea); (Coleus armaticus)
Ingredients: Neem (Azadirachta indica) oil, kerosene, plants of kolunchi or Purple Tephrosia (Tephrosia purpurea) and karpooravalli (Coleus armaticus) plant
"The essential oils of (Coleus aromaticus) and (Hyptis suaveolens) based on their in vivo and in vitro insecticidal efficacy may be recommended as nonphytotoxic herbal insecticides against (Tribolium castaneum) contamination. [Jaya, Singh P, Prakash B, Dubey NK. Insecticidal activity of (Ageratum conyzoides L.), (Coleus aromaticus Benth) and (Hyptis suaveolens L.) Poit essential oils as fumigant against storage grain insect (Tribolium castaneum) Herbst. J Food Sci Technol. 2014;51(9):2210-2215.
"Neem oil contains at least 100 biologically active compounds. Among them, the major constituents are triterpenes known as limonoids, the most important being azadirachtin .which appears to cause 90% of the effect on most pests. The compound has a melting point of 160°C and molecular weight of 720 g/mol. Other components present include meliantriol, nimbin, nimbidin, nimbinin, nimbolides, fatty acids (oleic, stearic, and palmitic), and salannin. [Campos EV, de Oliveira JL, Pascoli M, de Lima R, Fraceto LF. Neem Oil and Crop
Protection: From Now to the Future. Front Plant Sci. 2016;7:1494. Published 2016 Oct 13.
"Put a thin layer, about 1 1/2 centimetres, of fresh neem leaves in the bottom of whatever container you use to store grain. On top of that put in a layer of sun dried grain about 30 centimetres thick. Then put in another thin layer of neem, and on top of that another 30 centimetres of grain. Keep on alternating a thin layer of neem leaves with a thicker layer of grain up to the top of the container. Then close it up. Your grain will be safe from insects. [Neem Protects Stored Grain, G. Venkataramani, Agricultural Correspondent, The Hindu, Kasturi Buildings, Anna Salai, Madras ‑ 600 002, INDIA.]"
In laboratory trials contact toxicity of the extract was assessed against land leeches, houseflies, mosquitoes, rice weevil and flour beetle. In field trials, the repellency of the extract was assessed against land leeches, mosquitoes and simulium flies. In laboratory trials, the dosage required for 100 per cent mortality was 0.0005 gm/cm/sup 2/ for land leeches, 0.0157 gm/cm/sup 2/ for flour beetle. In field trials, the extract was found to be repellent against land leeches for 5 hours, mosquitoes for 4 hours and simulium flies for 5 hours. [SaxenaB.,DubeyD., &NairA. (2014). Studies on the Insecticidal and Repellent Properties of the Seed Extract of TephrosiaPurpurea (LINN) Pers. Defence Science Journal, 24(2), 43-48.