The effect of Beauveria bassiana inoculation on plant growth, volatile constituents, and tick (Rhipicephalus appendiculatus) repellency of acetone extracts of Tulbaghia violacea.

Pumla Staffa,Felix Nchu,Nkululeko Nyangiwe,Yakob Petro Nagagi,George Msalya

doi:10.14202/vetworld.2020.1159-1166

Abstract

Aim:The purpose of the present study was to evaluate the effects of Beauveria bassiana (Hypocreales) inoculum on plant growth, volatile constituents, and tick repellency of the extracts of Tulbaghia violacea (Amaryllidaceae).Materials and Methods:Eight-week-old potted seedlings of T. violacea were each inoculated with conidia of B. bassiana (strain SM3) suspended at a concentration of 1×106 conidia mL−1. Tissue colonization by fungal conidia was assessed after 3 weeks. Plant growth, volatile constituents, and tick repellency were assessed after 12 weeks post-treatment.Results:B. bassiana conidia successfully colonized leaf and root tissues of T. violacea. The growth of fungal hyphae out of the leaf and root sections occurred in 75% and 91.6% of plants, respectively. Inoculation of the plants with B. bassiana significantly (p<0.05) influenced root length and plant height but did not have substantial effects on weights and leaf number of T. violacea. While the fungus did not have significant effects on overall number of the volatile chemical constituents, significant variations in the quantity (area ratio) were observed in at least four compounds that were detected. In the tick repellency bioassay, high concentration (20 w/v%) of acetone extract from fungus-exposed plants produced the least repellent effect on Rhipicephalus appendiculatus larvae (Ixodidae), while at lower concentrations (5 w/v% and 10 w/v%) of acetone extracts of T. violacea, tick repellent activity of the extract of the fungus treatment was significantly improved and was comparable to commercial N,N-Diethyl-m-toluamide and the other treatments.Conclusion:Experimental fungal inoculation positively influenced plant growth in height and root length and tick (R. appendiculatus) repellency of acetone extracts of T. violacea at a concentration of 10 w/v% compared to the control treatment.

Highlights

Ticks are associated with many diseases of humans, livestock, and wildlife
Experimental fungal inoculation positively influenced plant growth in height and root length and tick (R. appendiculatus) repellency of acetone extracts of T. violacea at a concentration of 10 w/v% compared to the control treatment
It is estimated that a tick-borne diseases (TBDs) such as East Coast Fever (ECF) kills 1.1 million cattle in Africa resulting in economic losses

Summary

Introduction

Ticks are associated with many diseases of humans, livestock, and wildlife Developing countries, especially those in Africa, are heavily burdened by tick infestations and record huge annual economic losses [1]. Ticks and tick-borne diseases (TBDs) have adverse impacts on livestock and human health, placing a huge burden on the livelihoods of resource-poor farming communities in developing countries [2,3]. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/ publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

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