Controlling water hyacinth infestation in Lake Tana using Fungal pathogen from Laboratory level upto pilot scale

Abstract

Water hyacinth (Eichhornia crassipes) is one of the most dangerous aquatic weeds for LakeTana and other water body in Ethiopia. To reduce its invasion biological, chemical and physical control methods can be used. Use of natural biological enemies of the weed to discourage its propagation is one of the best recommended options by scientfic society.Among them, there are more fungi naturally a pathogen for water hyacinth and other plants. To use those patogenes to manage water hyacinth infestation in Lake Tana infected plant material by fungi were collected from three weredas (Amba Gyorgese, Dabat and Debarke) around Gondar at 20 Peasant associations (PAs) since Novmber 2015. The collection was done from infected Faba bean leaves and roots. All isolated fungus was attempted to infect the collected healthy water hyacinth in laboratory and green house. Among isolated fungus species Rhizoctonia solani, Aspergillus flatus, Tricothcium roseum, Fusarium spp and Aspergillus niger fungi show high moderate disease severity on the healthy water hyacinth at temporarey green house and laboratory. Disease severity scale was recorded using modified NAHEMA et al. (200). By following those experiments to show its efficiency, the effective pathogens on laboratory and green house were released to 16 m2open ponds since September 2016, in University of Gondar. In this study, we have recorded scientific data that shows the fungi were high potencial to attack healthy water hyacinth at above 26 oc and at less than 25 % humidity. From this research also we have observed the most infected water hyacinth by fungi have not produced flower and it can not re generate by seed in the next propagation sesaon.Finally, before directly release the fungi on Lake Tana its impacts were studied in the Goregora, at Kuame Michel kebela for a year in open ponds and in controlled wet land areas that not linked to the Lake by taking some common aquatic plants and fish from the Lake. Fortunatelly, those fungi have not impact on aquatic plant like Echinochloa and Cyperus papyrus grass, water quality and fish.

Problem of Water Hyacinth (Eichhornia crassipes (Mart.)) in Lake Tana (Ethiopia): Ecological, Economic, and Social Implications and Management Options

“…Water hyacinth is a serious hazard to lake transport due to its large foating mats of water hyacinth, which cause navigation difculty [37]. Besides, this weed threatens the majority of the lake in the Dembeya, Maksegnete, and Fogera districts, because these areas of the lake's edge have access to soils that have been eroded and contain nutrients (N and P) [4]. In general, although all the social efects of the water hyacinth are the indirect efects, the problem is more signifcant when it afects at large conditions.…”

“…Biological control is the most effective, efcient, and long-term method of large-scale removal of this weed, but it may take many years to achieve satisfactory results [14]. Insects and fungi have been studied extensively and then released to control water hyacinth [4]. However, most animals, with the exception of rabbits, do not readily consume the plant, possibly because its leaves are 95 percent water and have high tannin content [5].…”

“…Lake Tana is of signifcant ecological, religious, historical, and economic importance, and due to its rich biodiversity and cultural and historical signifcance, it was designated a United Nations Educational, Scientifc, and Cultural Organization (UNESCO) Biosphere Reserve in 2014 [3]. Lake Tana has a variety of uses, including fshing, electric power generation, transportation, drinking water for humans and animals, and a habitat for various birds [4]. Lake Tana's diverse aquatic ecosystems (lake, wetlands, and rivers) support unique endemic fsh species; 20 of Lake Tana's 27 fsh species are endemic to this lake's catchment [5].…”

“…Lake Tana is not only an economic and cultural source for Ethiopians but also an economic source for Egypt and Sudan. However, water hyacinth weed has become a challenge for the ecology of this lake [4].…”

Occurrence, Diversity and Potential of Fungal Pathogens Associated with Water Hyacinth (Eichhornia crassipes [Mart.] Solms) for Sustainable Biological Management in Ethiopia: A Review

“…Moreover, disclosed that 25 water hyacinth pathogenic fungal species belonging to 9 genera were identified of which Alternaria tenuissima (23.5%) and Aalternaria alternata (26.5%) were the most prevalent. On the other hand, Admas, et al [53] explained that Rhizoctonia spp followed by Fusarium spp was resulted a complete drying of water hyacinth with a severity value of 100% and 78.6% Dinknesh, et al [54].…”