  =One of the most frequently farmed crops is the tomato crop. Late blight is
the most prevalent tomato disease in the world, and often causes a significant
reduction in the production of tomato crops. The importance of tomatoes as an
agricultural product necessitates early detection of late blight. It is
produced by the fungus Phytophthora. The earliest signs of late blight on
tomatoes are unevenly formed, water-soaked lesions on the leaves located on the
plant canopy's younger leave White cottony growth may appear in humid
environments evident on the undersides of the leaves that have been impacted.
Lesions increase as the disease proceeds, turning the leaves brown to shrivel
up and die. Using picture segmentation and the Multi-class SVM technique, late
blight disorder is discovered in this work. Image segmentation is employed for
separating damaged areas on leaves, and the Multi-class SVM method is used for
reliable disease categorization. 30 reputable studies were chosen from a total
of 2770 recognized papers. The primary goal of this study is to compile
cutting-edge research that identifies current research trends, problems, and
prospects for late blight detection. It also looks at current approaches for
applying image processing to diagnose and detect late blight. A suggested
taxonomy for late blight detection has also been provided. In the same way, a
model for the development of the solutions to problems is also presented.
Finally, the research gaps have been presented in terms of open issues for the
provision of future directions in image processing for the researchers.
