The measures taken to avoid the incidence of a disease, reduce the amount of source that initiates and spreads the disease in the plant population. Proper measures taken minimize the loss caused by the disease and have traditionally been called control measures. The principle of plant disease management have two approaches that are directed towards a single disease in the crop or planning for the overall health of the crop. The common practice is to manage a particular disease but taking care of overall health of the crop is more profitable. The management of crop health involves a plan in which all disease of any significant nature in the crop are taken into consideration. This approach, though difficult, is one of more practical value for the farmer because they are interested in increasing the productivity of the crop and therefore, prefers a plan that can provide a safe guard against all possible diseases occurring in the area. If the cost involved in control measures fails to uplift the economic gain, even if the disease incidence is reduced, no farmer is likely to accept the recommendations for plant disease management. Therefore, the cost benefit ratio is a very important consideration in the application of control measures.
Plant diseases generally become visible when damage to the plant or plant part has occurred. The destroyed part or the plant part can’t be regenerated. The curative chemical treatments do not restore the damaged tissues. They eradicate or supress the pathogen at the site and save other tissues. Thus, the main objective of disease management strategy is to prevent the initiation and spread of a disease. The management of environment, host and pathogen is necessary. There is close relationship between the components. Management of the pathogen involves exclusion, avoidance, eradication, and protection of the host. Exclusion of the pathogen is the first principle of disease management. It involves the practices directed to prevent inoculum from reaching a pathogen free area. Another principle under management of the pathogen is based on protective measures. Cultural practices are employed to protect a crop from pathogens by eradicating or suppressing the pathogen and also by modifying the environment. The most important part of protection is the use of chemicals. At present, the use of fungicides as sprays over the crop is the most widely practised method of disease control.
Management of the host involves the practices directed to improve plant vigour and induce resistance through nutrition. It also involves the measures to protect the plant against insects and provides protection against attack of pathogens by chemical means. Resistance or tolerance of the plant to disease can also be increased through the use of micronutrients and chemicals. Physio-chemical environments consisting of soil, air, water, relative humidity in plant canopy, light, soil pH and temperature in which the plant grows as well as the biotic environment, mostly of the soil, influence various stages of a pathogen such as it survival, infection and disease development. They can also make the plant prone to attack of a disease. The environment may, therefore require modification to help a disease management strategy. The measures under management and crop management mostly through cultural practices.
Avoidance of the source causing disease
Many disease can be prevented by proper selection or change of land and modification in date of planting. The goal of these measures is to enable the host to avoid contact with the pathogen or to make sure that the susceptible stage of the plant and favourable conditions for pathogen do not coincide. Selection of geographical area for any crop is based on the suitability of prevailing temperature and humidity in the area for the crop. These factors influence incidence of the disease also. Many fungal and bacterial diseases are more severe in wet areas than in dry areas. Crops susceptible to these disease if grown in such areas like to fail due to serious disease incidence. If these crops are grown in dry areas with the help of irrigation disease incidence can be avoided.
Successful cultivation of a crop depends to a great extent on the selection of proper land. Many soil borne pathogens can be avoided by proper selection of site. The information about previous history of the field is necessary in preventing the development of the disease. In fruit orchards the selection of the site is of special importance. The fruit trees remain on the same soil for many years. If proper selection of site is not made at the time of planting the trees show signs of many abnormalities after a few years.
Time of planting
The incidence of most plant disease is severe when the susceptible stage of plant growth coincides with favourable weather conditions for pathogen activity. This can be escaped by adjusting the time of planting of the crop.
Selection of seed
Many disease are introduced in the crop only through the seed or other propagating material. Such disease can be prevented effectively by using disease free planting material for plantation. Disease incidence can be minimized by proper selection of pathogen free field and it is the most effective method of control of certain disease.
Some crop varieties escape damage from disease because of their growth characters. This disease escaping quality is not due to their genetic resistance but because of characteristics of growth and time of maturity. Resistant varieties should be cultivated to avoid the occurrence of diseases.
Modification of cultural practices
Spacing between plants, time and amount of irrigation, quantity and quality of fertilizers or organic manures, time and method of planting, mixed cropping, depth of sowing etc., are many cultural practices which influence incidence and severity of diseases. Necessary modifications in these practices help in reducing disease incidence and avoid loss in the crop yield.
Soil sickness is a well-known phenomenon in cultivation of crops. When the same crops is raised year after year in the same field, apart from nutritional deficiency, the soil borne pathogens easily penetrate in the soil and increase the population. After sometime, the soil becomes so heavily infested that it becomes unfit for cultivation of that particular crop.
Sanitation and eradication of sources on which the pathogens is present in the field helps in avoidance of disease. Removal of diseased plants or their diseased parts from the field is necessary. Field sanitation, like plant sanitation, is essential for control of soil borne pathogens. Destruction of the diseased part parts by burning in the field constitutes field sanitation.
These all measures are taken to prevent the diseases before occurrence. Because after the occurrence of disease it is difficult to manage the diseases. The measures taken to avoid the incidence of a disease always reduce the source that spreads the disease in the plant population. Proper measures taken minimize the loss caused by the disease. In Pakistan farmers are mostly uneducated, they always take measures after the occurrence of disease. So it is necessary to educate the farmers and avoid losses due to mismanagement. Jazz Bakhabar Kissan play a vital role in creating awareness among the farmers about the general principles of diseases management. It has introduced mobile application for the famers that enables the farmers to avail information regarding good cultivation practices for increasing overall yield. Application provides management techniques with regards to maximum crops, fruits and vegetables. It also offer services to farmers through SMS (Short Message Service), VMS (Voice Message Service), IVR (Interactive Voice Response) & a dedicated Website to help farmers increase their production. Information regarding best agricultural practices are sent via SMS & VMS to every subscribed farmer to increase their yield as well as to enhance farmer’s awareness.