Synergism of three botanical termiticides as wood protectants against subterranean termites, Macrotermes subhyalinus (Rambur, 1842)

Abstract

Background: The increased interest in the harmful effects of most chemical pesticides on the ecosystem has continually served as an impetus to search for safer and eco-friendly pesticides from plant origin. In this study, the termiticidal potentials of extract mixtures of Azadirachta indica (A. Juss.), Nicotiana tabacum (L.), and Jatropha curcas (L.) against Macrotermes subhyalinus (Rambur, 1842) infesting Triplochiton scleroxylon (K. Schum) wood blocks were investigated in the field (open and under shade) and laboratory conditions. Weight loss in wood blocks, level of wood damage, and termite mortality were used as indices of wood protection potential of the botanical mixtures. The level of repellent ability of the extracts mixture was also determined. For the laboratory bioassays, ten termites (worker/soldier) were used per treatment and each treatment was replicated thrice. Profile of components of the three mixtures was also obtained using head space-solid-phase micro-extraction, gas chromatography-mass spectrophotometry (HS-SPME, GC-MS) analysis. Results: Extracts of A. indica plus N. tabacum achieved 100% mortality of worker within 4 h while those of N. tabacum plus J. curcas and A. indica plus N. tabacum plus J. curcas achieved 100% mortality of termites at 6 h posttreatment. Also, extract of A. indica plus N. tabacum and A. indica plus N. tabacum plus J. curcas evoked 100% mortality of soldier termites at 6 h. Termites exposed to N. tabacum plus J. curcas for 1, 2, 3, and 4 h were the most repelled at 73, 87, 73, and 73%, respectively. The extract of J. curcas plus A. indica plus N. tabacum offered the highest protection against termite damage in the open field (6.17%). The botanicals were ineffective under shade. Insecticidal compounds like (S)-3-(1-Methyl-2-pyrrolidinyl) pyridine; Methyl ester, Hexadecanoic acid; (Z, Z)-9, 12-Octadecadienoic acid; Anthracene; 2-Hydroxy-Cyclopentadecanone; and n-Hexadecanoic acid were found in the extracts. Conclusion: These results suggest that the botanical mixtures could confer some protection against termites. Also, the knowledge about the components and varied level of potency under different conditions may be vital in developing biorationals against M. subhyalinus.

Efficacy os Some Plant Extracts against Termites Under Controlled Conditions

“…The ability of various plant based extracts observed now to elicit termite mortality is in agreement with earlier studies of Singh and Kumar (2008), Shiberu et al, (2013), andEkhuemelo et al (2017). However, the termite mortality rate depends on the caste of the termite, the chemical composition of the plant product, and exposure time (Ajayi et al, 2020). The higher potency of neem (fresh and fermented extracts) and tulsi (fermented extracts) to Odontotermes sp.…”

Termites and maize crops: assemblage composition, damage level, and varietal sensitivity in contrasting agro-ecological zones of the Republic of Benin

“…Worldwide, chemical insecticides are the main method used by farmers to overcome termite damages (Logan et al, 1990;Akutse et al, 2011;Otieno, 2018). However, synthetic termicides have harmful effects on human health and environment (Oladipo-nee Ajahi et al, 2020). Unfortunately, Loko et al (2019a) reported the use of highly hazardous chemical insecticides by Beninese farmers to fight termite pests in maize plantations.…”