There are limited referenced fairly related for biological control common water hyacinth by fungi as bio-herbicides like Alternaria eichhorniae. I attached three references, could be useful to answer your question.
Y.M. Shabana, R. Charudattan, M.A. Elwakil. (1995). Evaluation of Alternaria eichhorniae as a Bioherbicide for Waterhyacinth (Eichhornia crassipes) in Greenhouse Trials. Biological Control, 5(2):136-144
Ayyaru, et al., (2011). Integrated biological control of water hyacinths, Eichhornia crassipes by a novel combination of grass carp, Ctenopharyngodon idella (Valenciennes, 1844), and the weevil, Neochetina spp. Chinese Journal of Oceanology and Limnology, 29 (1): 162-166, 2011
Chu, et al., (2006). Invasion and control of water hyacinth (Eichhornia crassipes) in China. J Zhejiang Univ Sci B. 7(8): 623–626.
Alternaria eichhorniae can be used against Waterhyacinth , but as I know it isn't recorded in Iraq , so it is difficult to apply such these fungi in aquatic ecosystem.
The attached review publication of Dagno et al 2012 on mycoherbicides on water hyacinth provides some information.
Begin of the 2000's there has been a collaborative DANIDA IMPECCA project on mycoherbicides. You may look for the final report of this project. Fen Beed of IITA has been involved in this project and may be of help. Fen Beed
As the item that Dr. Henri M. M. Maraite refers to in attached items , Rhizoctonia solani can be used as a biocontrol agent against water hyacinth in adding to another fungi.
I would strongly suggest to contact Dr. Ernesto Favela from Mexico. He has a project on water hyacinth where they are purifying polysaccharides from it ([email protected])