Exploration of biological and chemical control agents for the suppression of Colletotrichum gloeosporioides (Anthracnose disease) of chilli pepper (Capsicum annuum) in Ethiopia | |
| Author | Jebessa, Mitiku Tesso |
| Call Number | AIT Diss. no.AS-05-06 |
| Subject(s) | Hot peppers--Ethiopia Anthracnose |
| Note | A dissertation submitted for the partial fulfillment of the requirements for the degree of Doctor of Technical Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. AS-05-06 |
| Abstract | Anthracnose disease of chilli pepper (Capsicum annuum) caused by Colletotrichrun gloeosporioides was a severe problem for Ethiopian pepper production although surveys were not made. The quality and quantity of pepper pods have been much affected providing no return for the farmers who have made pepper production their living. Dye factories in the country could not also get raw materials of pepper for their factories. Therefore, one of the purposes of this study was to make surveys in major pepper growing regions of Ethiopia and to isolate and identify C. gloeosporioides isolates causingg anthracnose disease of chilli pepper (CC annum). The study also consisted of laboratory experiments to find biological agents and fungicides which are able to control C. gloeosporioides species attacking chilli pepper pods affecting both the quality and quantity of the product. Surveys were made in Western, Central and Southern pepper growing regions of Ethiopia in the year 2004 and sixteen isolates were brought to the Mycological Laboratory at Ambo, Ethiopia. Upon isolation and identification four isolates; 4(2)R, 4(2)W, 8(2)B and 8(2)W were identified as C. gloeosporioides species. Three Trichoderma species, namely Trichoderma harzianum, Trichoderma koningii and Trichoderma pseudokoningii were tested in vitro suppression of their biological potential to control C. gloeosporioides isolates and T. koningii exhibited the best result in controlling the four isolates of the fungus followed by T. pseudokoningii and T. harzianum. The reactions of Trichoderma species in controlling the fungus were both mechanisms of mycoparasitism and antibiosis. The four isolates also showed different reaction to the Trichoderma species. Three fungicides, score, mancozeb and ridomil were used in the laboratory screening test against C. gloeosporioides isolates. In most cases the fungicide score was found inhibiting the growth of the isolates throughout the incubation period although in few cases mancozeb and ridomil also gave relatively lesser growth of the colonies over a score fungicide. The fungicide score vas selected and further tested for its proper dose to be used against isolate 4(2)R of C. gloeosporioides. There were four levels of the fungicide tested and four of them yielded positive results in their in vitro control of isolate 4(2)R although level 50% was found with a least effect on the growth of the isolate. The results of the four different rates obtained by splitting the manufacturer's recommended rate in this experiment proved that manufacturer's recommendation is the best to be used in Ethiopia although the remaining three rates can also be used so that the amount of the fungicide to be applied can be reduced to avoid the several side effects of the fungicide on the environment provided that the use of the rates can meet the objective of controlling anthracnose disease of chilli pepper caused by C. gloeosporioides |
| Year | 2005 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. AS-05-06 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Aquatic Systems(AS) |
| Chairperson(s) | Ranamukhaarachchi, S.L.,; |
| Examination Committee(s) | Shipin, Oleg;Clemente, R.S.;Manoch, Leka; |
| Scholarship Donor(s) | Alemaya University, Ethiopia; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2005 |