Open Access
Research (Published online: 20-06-2020)
20. The effect of Beauveria bassiana inoculation on plant growth, volatile constituents, and tick (Rhipicephalus appendiculatus) repellency of acetone extracts of Tulbaghia violacea
Pumla Staffa, Nkululeko Nyangiwe, George Msalya, Yakob Petro Nagagi and Felix Nchu
Veterinary World, 13(6): 1159-1166

Pumla Staffa: Department of Horticultural Sciences, Cape Peninsula University of Technology, Bellville, Symphony Way, Bellville, Cape Town, 7535, South Africa.
Nkululeko Nyangiwe: Department of Agriculture, Dohne Agricultural Development Institute, Private Bag X15, Stutterheim, 4930, South Africa.
George Msalya: Department of Animal, Aquaculture and Range Sciences, Sokoine University of Agriculture, P. O. Box 3004, Chuo Kikuu, Morogoro, Tanzania.
Yakob Petro Nagagi: Livestock and Human Diseases Vector Control Division, Tropical Pesticides Research Institute, P. O. Box 3024, Arusha, Tanzania.
Felix Nchu: Department of Horticultural Sciences, Cape Peninsula University of Technology, Bellville, Symphony Way, Bellville, Cape Town, 7535, South Africa.

doi: www.doi.org/10.14202/vetworld.2020.1159-1166

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Article history: Received: 31-12-2019, Accepted: 04-05-2020, Published online: 20-06-2020

Corresponding author: Felix Nchu

E-mail: felixnchu@gmail.com

Citation: Staffa P, Nyangiwe N, Msalya G, Nagagi YP, Nchu F (2020) The effect of Beauveria bassiana inoculation on plant growth, volatile constituents, and tick (Rhipicephalus appendiculatus) repellency of acetone extracts of Tulbaghia violacea, Veterinary World, 13(6): 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.

Keywords: Beauveria bassiana, fungal endophyte, secondary metabolites, tick repellency, tick toxicity, Tulbaghia violacea.