Agriculture, being a very vast and varied domain of knowledge with over a hundred crops distributed in different geographic regions having varied climatic conditions, building such a team in every domain of knowledge of agriculture is itself a challenging and huge task. Knowledge engineers gather knowledge from domain experts and put it in such a form that system can use for inferring and reasoning using a knowledge representation technique.In this study, the researcher proposed knowledge based system for Mango fruit Disease Diagnosis and Treatment, an expert system that will use for recommending farmers and agronomy experts about disease diagnosis and treatment.
It enables domain experts to build effective expert system in their fruit with minimal intervention of knowledge engineers and programmers.Farmers and agronomy expert require timely, accurate and location specific information in relation with different aspects of farming like the pests, diseases, weeds and fertilizer management, etc. for their crops from agricultural experts. On the other side, the complexity of a whole farming process is growing because it is constrained by many factors such as requirements, goals, regulations, etc.
that farmer must satisfy or consider. To provide such information and to achieve an optimal crop plan, the automation is provided by computer-based systems termed as advisory systems. An advisory system supports the farmers and experts in getting advices on many activities in farming process 23. Expert Systems (ES) can be used for extending the research to farmers and it can work as a problem-solving tool for them. ES on agriculture can have a powerful mechanism with extensive potential to solve the problems related to agriculture.
ES are designed to emulate the logic and reasoning processes that an expert would use to solve a problem 24. 1.2 STATEMENT OF THE PROBLEMAgriculture is the predominant activity for most rural households in Ethiopia. The sector is mainly based on small holder farms and contributes about half to the total Gross Domestic Product (GDP) of Ethiopia and the livelihoods of more than 80% of the citizens 25. The small-scale farming accounts for 95% of the total area under crop and more than 90% of crop output.
Fruit crops play an important role in the national food security of people around the world. They are generally delicious and highly nutritious, mainly of vitamins and minerals that can balance cereal-based diets. Fruits supply raw materials for local industries and could be sources of foreign currency. Moreover, the development of fruit industry will create employment opportunities, particularly for farming communities. In general, Ethiopia has great potential and encouraging policy to expand fruit production for fresh market and processing both for domestic and export markets. Besides, fruit crops are friendly to nature, sustain the environment, provide shade, and can easily be incorporated in any agro-forestry programs 26.The mango, because of its attractive appearance and the very pleasant taste of selected cultivars, is claimed to be the most important fruit of the tropics and has been touted as ‘king of all fruits’. The fruit contains almost all the known vitamins and many essential minerals.
The protein content is generally a little higher than that of other fruits except the avocado. Mangos are also a fairly good source of thiamine and niacin and contain some calcium and iron 27.Mango is one of the world’s most important fruits of the tropical and subtropical countries and is cultivated extensively as a commercial fruit crop in India, China, Indonesia, Thailand and Mexico. By virtue of its wide range of cultivation, delicious taste, super flavour, very high nutritive and medicinal value as well as great religion historical significance, it is regarded as the “King of the fruits” 28. Mango is the most important fruit and it is the second in area coverage after banana in southern region of Ethiopia 29. The mango crop is also cultivated in Ethiopia and while in southwest Ethiopia, mango is the first fruit crop grown 10. The area of mango production in the different regions is about 3789.
47 ha in Oromia, 3375.89 ha in SNNPR, 652.56 ha in Benishangul Gumz, 246.85 ha in Amahara, 180.41 ha in Gambella, 44.5 ha in Dire Dawa, 33.52 ha in Somali, 118.20 in Tigray and 367.
24 ha in Harari. The total area allotted for mango is about 8808.64 ha and the country annual production of mango from all mango grower regions is about 697,507 quintals 11.Mango tree is attacked by different insects and diseases such as , Anthracnose, Bacterial Black spot, Fruit fly, mango gall flies, Mango leaf coating, Mites, Mango seed weevil, Mealy bug,Powdery mildew, Scale, Spider mites, Mango tip borer, Stem-end rot, Termite, Thrips and White flies. The major insect pest of mango is the white mango scale insect, Aulacaspis tubercularis (Hemiptera: Diaspididae). It has been recorded mainly from plants belonging to four families: Palmae, Lauraceae, Rutaceae and Anacardiaceae 13.
This insect is a serious pest in mango especially on the late cultivars 14.White mango scale insect is a serious pest that injures mangoes by feeding on the plant sap through leaves, branches and fruits, causing defoliation, drying up of young twigs, poor blossoming and so affecting the commercial value of fruits and their export potential especially to late cultivars where it causes conspicuous pink blemishes around the feeding sites of the scales. In nurseries, severe early stage infestation retards growth.Plant diseases are one of the most important reasons that lead to the destruction of plants and crops. Detecting those diseases at early stages enables us to overcome and treat them appropriately 30.
This process requires an expert to identify the disease, describe the methods of treatment and protection. Identifying the treatment accurately depends on the method that is used in diagnosing the diseases. Expert systems help a great deal in identifying those diseases and describing methods of treatment to be carried out taking into account the user capability in order to deal and interact with expert system easily and clearly. This requires that the users should be competent using expert systems. An expert system was developed using two different methods of plant diagnosis: step by step descriptive and graphical representational methods. Present expert system plays the role of an agricultural engineer and provides the user with different methods of diagnosis and treatment 30.
Identifying the plant diseases is not easy task; it needs experience and knowledge of plant and their diseases. Moreover, it requires accuracy in describing the symptoms of plant diseases. A person can depend on a system that posses experience and knowledge (expert systems) to enable him/or her in identifying and type of disease, making the right decision and choosing the right treatment like the disease.The methods that expert system uses differ from one system to another because that depends on the user’s primary knowledge of the case.
Decision making depends mainly on the way of receiving that knowledge 30. The major production constraints indicated by Tewodros Bezu 31 were water shortage or erratic rainfall (79%) followed by pest (75.7%) problems. Lack of knowledge and recommended production practices (nutrition, pruning, pest management etc.) and post-harvest losses were also noted as major problems of the mango growers.
It is in agreement with CSA 4 report that stated mango production in Ethiopia fluctuates because of occurrence of diseases and lack of proper management 4. Agriculture requires information and application of knowledge from different interacting fields of science and engineering to make a suitable decision-making that in turn depends on interplay of these data and knowledge. This needs agricultural specializations and technical awareness in farmer or a human expert to help the farmers in decision making.
Existence of agricultural specialization and full awareness with technological progress in a farmer is a very rare thing in our country 32. Human experts are not always available, may not be accessible to every famer or if available consultation may be very expensive. The other complications are that the decisions in agricultural practice depend on large number of factors. Thus even for a human experts it becomes awkward to take all factors into consideration while making a decision. All such problems have resulted in the development and evolution of the concept of expert system 32.The use of information technologies improved the knowledge base and increased the capacity to control the production practices which in turn reduces the thereat and uncertainty, improved the efficiency of decision making and better recognized the variations in divers influencing features thus depicting enhanced management policy for the farm 33.
In addition, it is possible to store much of the information that an expert needs to make decisions and can make them on hand for others; therefore the notion knowledge based agriculture has an adequate prospective to improve the agricultural production 30.The purpose of human to do cultivation is to meet the needs of growing food along with the increase of population. In addition the plant also serves as a provider of oxygen to the human respiratory system as well as the aesthetic and the beauty that can be enjoyed by humans.Therefore, research on plant cultivation continues to be done to get a high yielding plant that is superior, responsive to fertilization and resistance to pests and plant diseases. Studies on the pests control and diseases of plants grow rapidly along with grower efforts to get optimal results from its cultivated plants.
Pest and disease attack and destroy crop cultivation efforts and result in reduced quality and quantity of the results obtained 34. Problems of pests and plant diseases are the main obstacles in increasing agricultural production. An estimated one-third of the world’s agricultural production has been marred by more than 20,000 species of destructive organisms including pests and plant diseases 34.Damage occurs, both on the field during the cultivation process and warehouse storage. These conditions will significantly affect the income of farmers and the world’s food supply.
Destructive organisms cover all forms of life that can destroy plants and classified into 3 groups. The first group is the pest, i.e. animal or nuisance animals and destroying plants such as insects, mollusks and mammals.
The second category is a disease caused by micro bodies such as fungi, bacteria and viruses. The third is the weed plants that are not expected its presence on an agricultural area 34. Pests and plant diseases are still a complicated issue for owners of the plants, especially for those who do not have the basic knowledge of crop cultivation. The problem becomes more complex due to many types of pests and plant diseases. To differentiate the cause of damage to crops, long enough experience are needed so there is no error in concluding the cause in order to take the right decision in an effort to control 34.
On the other hand, a number of difficulties have been encountered in developing countries like Ethiopia. First, in agriculture decision making, an agronomist expert cannot make a diagnosis with high accuracy due to lack of modern equipment caused by restricted financial resources.Second, there are not sufficient good agronomist expert to serve the whole population or to cover the whole area of agronomy area. Third, in the country, only traditional treatment and techniques are also employed which are based on experience which is often not documented for the next generation of agronomy expert or farmers.There are several major application areas of expert system such as agriculture, education, environment and medicine. These four applications are widely used among the practitioners. The components and application of expert system for agriculture is same as that of other three applications.
The experience and knowledge of a human expert is captured in the form of IF-THEN rules and facts which are used to solve problems by answering questions typed at a keyboard attached to a computer on such diversified topics, for example, in pest control, the need to spray, selection of a chemical to spray, mixing and application, optimal machinery management practices, weather damage recovery such as freeze, frost or drought, etc. Now-a-days expert system in agriculture is employed more for diagnosis and management of economically significant pest problems like diseases and insects of crop plants 35. Now-a-days, expert system is widely used in agriculture exclusively for diagnosing and managing pests.
These pest problems are mainly dependent upon human experts for their diagnosis and getting recovery. The involved human experts are very scarce, inconsistent in their day-to-day decisions, unable to comprehend large amounts of data quickly, unable to retain large amounts of data in memory, subject to deliberate or inadvertent bias in their actions and can deliberately avoid decision responsibilities. Human experts are not always available whereas the computer based expert system can be used anywhere, any time. Expert system offers an environment where the good capabilities of humans and the power of computers can be incorporated to overcome many of the limitations. Expert system increases the probability, frequency and consistency of making good decisions, additive effect of knowledge of many domain experts, facilitates real-time, low-cost expert-level decisions by the non-expert, enhance the utilization of most of the available data and free the mind and time of the human expert to enable him or her to concentrate on more creative activities 35. Therefore the researcher has been developed knowledge based system in mango fruit in order to diagnose various pests and taking management decisions for the benefit of farmers and experts. Agriculture and plantation is an important and interesting research area everywhere in the world and Ethiopia is no exception.
Nowadays available land area for a plantation is becoming scarce. This scarce resource is frequently wasted through our bad practices and improper management. Cultivation is a more economical but complex process. Identifying, diagnosis and treating the mango diseases for the maximum yield production involves a sequence of tasks. These tasks and the whole process need a lot of expert knowledge and experience. But unfortunately, people having this type of knowledge are very limited.
Their assistance is not available when the person who is going to cultivate needs it.It is therefore the purpose of this study is to explore appropriate rule based approaches for developing and implementing knowledge based system for mango diseases diagnosis and treatment. To this end, this study will attempt to explore and answer the following research questions:• What type of knowledge is required to design a knowledge base system which can assist experts in diagnosis and treatment of Mango diseases? • What suitable domain knowledge exists in an explicit and tacit form for diagnosis and treatment of Mango diseases? • How to design KBS for Mango disease to advice agronomy experts? • What are the appropriate trends or techniques taken by experts to diagnosis mango disease?• How the qualities of Mango disease diagnosis and treatment processes improved using knowledge based system? • How to acquire, model, represent, and implement KBS prototype for diagnosis and treatment of Mango diseases? • How to evaluate the performance of KBS prototype developed for mango diseases diagnosis?