Occurrence and diversity of fungal pathogens associated with water hyacinth and their potential as biocontrol agents in the Rift Valley of Ethiopia

E.A Lantinga,Firehun Yirefu,P.C Struik,Taye Tessema

doi:10.1080/09670874.2016.1277046

E.A Lantinga, Firehun Yirefu + Show 2 more

Open Access

https://doi.org/10.1080/09670874.2016.1277046

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Abstract

ABSTRACTWater hyacinth poses serious socio-economic and environmental problems in Ethiopia. To integrate fungal pathogens into water hyacinth management, a survey was conducted in the Rift Valley of Ethiopia. Based on morphological characterization and DNA sequencing, 25 fungal species were identified that belong to nine genera. Alternaria tenuissima, A. alternata, Aspergillus niger, Phoma sp., Curvularia trifolii, Mucor fragilis, M. racemosus, A. fumigatus, Fusarium oxysporum, and F. equiseti were the most common fungi detected. However, their occurrence was influenced by water wave action, temperature, season, and altitude. Among the fungal pathogens, A. alternata, A. tenuissima, F. oxysporum, F. equiseti, and Neofisicoccum parvum were highly pathogenic to water hyacinth. Alternaria alternata and A. tenuissima did not cause disease symptoms on ecologically important plant species (e.g. Noug, Tef, and Coffee). Application of the fungal pathogens on water hyacinth plants also showed 11%–67%, 22%–72%, 15%–55%, and 12%–50% reduction in fresh weight, dry weight, plant height, and root length of water hyacinth, respectively. This study suggests that fungal species have the potential to control water hyacinth biologically and provides baseline data for biological control efforts in the future.

Highlights

Water hyacinth [Eichornia crassipes (Mart.) Solms] is one of most noxious aquatic weeds in the world
In an effort to integrate fungal pathogens into water hyacinth management, this paper investigates the diversity of fungal pathogens associated with water hyacinth in Ethiopia, their impact on the growth of water hyacinth plants and their safety on important plant species
Morphological and molecular characteristics and fungal species identity In total, 25 isolates sporulated within 9 days of incubation and colonies formed different colors on potato dextrose agar (PDA)

Summary

Introduction

Water hyacinth [Eichornia crassipes (Mart.) Solms] is one of most noxious aquatic weeds in the world. In Ethiopia, water hyacinth (Pontederiaceae) was reported from Koka Lake and the Awash River about 60 years ago (Stroud 1994; Firehun et al 2013) Since it has manifested itself on a large scale in many water bodies, including rivers, lakes, reservoirs, irrigation supplies and drainage systems (Stroud 1994; Rezene 2005; Taye et al 2009). Biological control of water hyacinth, which involves the use of natural enemies (i.e. insects and fungal pathogens) has been reported to be the most economical and sustainable method of control (Firehun et al 2013). Recommendations have been made to integrate fungal pathogens with insects to improve biological control of water hyacinth due to the insect feeding damage facilitating pathogenic infections of water hyacinth leaves (Martinez & Gutierrez 2001)

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