Agriculture is one of the strongest pillars of the Indian economy. Plants are important as they are the source of energy supply to mankind. Approximately 70% of the Indian economy depends on agriculture for their livelihood. But this is affected by the disease which causes lower agricultural productivity. The farmers encounter difficulties in their detection of plant diseases. Diseases can affect the plant at the time of sowing and harvesting and it leads to low productivity and lowers the economic level. So, there is a need to mitigate this issue by computer techniques and machine learning methods. This paper presents an overview of various classification techniques in machine learning that helps in plant disease detection. The emergence of agriculture is one of the strongest pillars in the Indian economy. Plants are important as they are the source of energy supply to mankind. Approximately 70% of the Indian economy depends on agriculture for their livelihood. But this is affected by a disease that causes lower agriculture productivity. The farmers encounter difficulties in their detection of plant diseases. Diseases can affect the plant at the time of sowing and harvesting and it leads to low productivity and lowers the economic level. So, there is a need to mitigate this issue by computer techniques and machine learning methods. This paper presents an overview of various classification techniques in machine learning that helps in plant disease detection. The emergence of accurate techniques leads to impressive results. accurate techniques lead to impressive results.