Toxicity potential of heartwood extractives from two mulberry species against Heterotermes indicola

Babar Hassan,Mark E Mankowski,Nasir Mehmood,Muhammad Misbah-Ul-Haq,Sohail Ahmed

doi:10.4067/s0718-221x2019005000203

Babar Hassan, Mark E Mankowski + Show 3 more

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https://doi.org/10.4067/s0718-221x2019005000203

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Abstract

Choice and no-choice tests were run to evaluate natural resistance of the woods of two Morus species (Morus alba and Morus nigra) against the subterranean, Heterotermes indicola, under field conditions. Toxicity, antifeedant and repellency potential of the heartwood extractives was also investigated under laboratory conditions. Heartwood extractives were removed from wood shavings by using methanol or an ethanol: toluene (2:1) mixture. Results of choice and no-choice tests with sap and heartwood blocks exposed to termites, showed that both mulberry species were resistant to termites but in comparison, Morus alba wood was more resistant than Morus nigra to termite feeding as it showed <5 % weight loss after 90 days. Termites exhibited a concentration dependent mortality after exposure to either mulberry speciesâ heartwood extractives. The highest termite mortality occurred after termites were exposed to filter paper treated with Morus alba extractives at a concentration of 5 %. At this concentration, antifeedancy and repellency were calculated to be 91,67 and 84 % respectively. . Our results also showed that extractives from either mulberry species imparted resistance to vacuum-pressure treated non-durable Populus deltoides wood. Termite mortality was greater than 75 % after feeding on Populus deltoides wood treated with extractives from Morus alba. Solvent only (methanol) treated Populus deltoides controls, showed a minimum weight loss of 2,69 % after 28 days. These results suggest that Morus alba extractives have antitermitic properties and may be potentially useful in the development of environment friendly termiticides.

Highlights

Heterotermes spp. are structure-infesting termites that account for a significant amount of the damage attributed to subterranean termites in southern Asia, areas of Pakistan
Comparative susceptibility/resistance tests of woods against H. indicola have indicated that Dalbergia sissoo, Azadirachta indica, Syzygium cumini and Pinus roxburghii, were resistant while Populus euramericana, Bauhinia variegate, Mangifera indica and Populus deltoides were ranked as susceptible to termite attack (Dugal and Latif 2015, Afzal et al 2017)
Logs of Morus alba (L.), Morus nigra (L.) and Populus deltoides were purchased from a timber market located at Jhang Road, Faisalabad, Pakistan

Summary

Introduction

Heterotermes spp. are structure-infesting termites that account for a significant amount of the damage attributed to subterranean termites in southern Asia, areas of Pakistan. Heterotermes indicola previously limited to the Indian subcontinent, and the Arabian Peninsula , has spread to other areas and is commonly encountered in Punjab, as well as in the Khyber Pakhtunkhwa provinces in Pakistan (Misbah-ulHaq et al 2015). Comparative susceptibility/resistance tests of woods against H. indicola have indicated that Dalbergia sissoo, Azadirachta indica, Syzygium cumini and Pinus roxburghii, were resistant while Populus euramericana, Bauhinia variegate, Mangifera indica and Populus deltoides were ranked as susceptible to termite attack (Dugal and Latif 2015, Afzal et al 2017). Heartwood compounds extracted from D. sissoo, P. roxburghii, Tectona grandis, Cedrus deodara, Eucalyptus camaldulensis, Acacia arabica, Betula utilis, S. cumini and several other durable woods.

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