Controlling Water Hyacinth in Lake Tana Using Biological Method at Green House and Pond Level

Abstract

Water hyacinth (Eichhornia crassipes) is one of the most dangerous aquatic weeds for Lake Tana. To minimize invasion; biological, chemical and physical control methods can be used. Biological control based on the use of natural enemies of the weed to discourage its development was the best option. Plant pathogenic associated with naturally infected Faba bean by fungus was conducted at different sites with the objective of study the pathogen city indigenous fungi on water hyacinth to manage its spread on Lake Tana. Infected fungus plant samples were collected from three weredas (Amba Gyorgese, Dabat and Debarke) around Gondar at 20 Peasant association (PAs), The collection were done for infected Faba bean leaves and roots and isolated using Potato Dextrose Agar medium. Highest disease incidence per plant was recorded in water hyacinth plants using Using Modified Naseema et al. (2001) disease severity rating scale by inoculated with Rhizoctonia solani spp. Aspergillus flavus, Tricothcium roseum, Fusarium spp and Aspergillus niger show high moderate disease severity and tissue death at green house and pond level. Those fungus were released on September 2016 to prepared open pond at 16m 2 and water hyacinth was started severely attacked on November 2016, its disease incidence was 55% at 23˚C and humidity 39%, in December 2016 its disease incidence was 58.4% at humidity 31% and 23˚C, in January 2017 disease incidence was 65% at 26˚C and humidity 25% and in Feb 2017 not record disease incidence because all leaves are attacked and dry and Disease severity was 100%.However, in April 2017 due to the climate conditions becomes cold and rain the dried water hyacinth started make new shoot and at this time the disease severity was 90%. Some species of Fungi found in Faba bean leaf and root can eradicate the healthy water hyacinth at above 26˚C and at less than 25% Humidity.

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“…A release of 1000 insects per (1000 m 2 ) in two sites exerted an efficacy around 90% of the water hyacinth infestation (Ding et al 2001). According to the experiment of Admas et al (2017)…”

Determinants of environmental conservation in Lake Tana Biosphere Reserve, Ethiopia

“…Conservation of many protected areas and biosphere reserves including many water bodies has faced environmental problems (Admas et al., 2017) whereby water hyacinth ( Eichornia crassipes) is the convoluted problem of Lake Tana (Asmare, 2017; Admas et al., 2017). Carelessness and lack of conservation efforts in the country brought invasive species from the southeast to northwest Ethiopia (Admas et al., 2017). Water hyacinth infestation in Ethiopia was known to appear in Koka reservoir in 1956 was dispersed and now became relentless to Lake Tana in the Blue Nile basin (Admas et al., 2017).…”

“…Carelessness and lack of conservation efforts in the country brought invasive species from the southeast to northwest Ethiopia (Admas et al., 2017). Water hyacinth infestation in Ethiopia was known to appear in Koka reservoir in 1956 was dispersed and now became relentless to Lake Tana in the Blue Nile basin (Admas et al., 2017). Lake Tana and its surrounding wetlands are of immense ecological value providing the means of existence for 2–3 millions of people, however escalating human activity is causing the destruction of this unique ecosystem degraded due to high pressure on natural resources (Zur Heide, 2012).…”

“…Lake Tana and its surrounding wetlands are of immense ecological value providing the means of existence for 2–3 millions of people, however escalating human activity is causing the destruction of this unique ecosystem degraded due to high pressure on natural resources (Zur Heide, 2012). Low level of local conservation while practicing a wide range of activities has become a critical problem for Lake Tana that made water hyacinth infestation hazardous (Admas et al., 2017; Asmare, 2017).…”

“…Different researches on Lake Tana regarding potentials for tourism development (Zur Heide, 2012) as well as problems giving priority to a fishery, water hyacinth infestation and many other related ecological problems were done on the present study area (Tewabe, 2015; Asmare, 2017; Worku, 2017)). Furthermore, they emphasized on the natural science dimensions of problems over the lake (Admas et al., 2017) giving less emphasis to the institutional, political and human dimensions of conservation with which the determinant factors of conservation remain uncovered. Hence, the aim of this research is an investigation of factors for the conservation of Lake Tana Biosphere Ecosystem with adequate triangulation of human and political dimensional factors.…”