Page 229 - Handbook of Deep Learning in Biomedical Engineering Techniques and Applications

220 Chapter 8 A review on plant diseases recognition through deep learning

symptoms of the plant disease. Deep learning is a subversion of
machine learning divided into two eras: one from 1943 to 2006,
which accommodates popular algorithms such as backpropaga-
tion, LeNET architecture, and Neocognitron, and another from
2012 onward, which includes algorithms for healthcare sectors,
predictions, recognition, and classifications considered as the
breakthrough in the deep learning field. Many advanced
concepts were bloomed in deep learning along with a variety of
metrics such as precision and recall, training/validation accuracy
and loss, F1 score, and classification accuracy to evaluate the
performance. This chapter provides a comprehensive description
of deep learning models to detect and visualize various plant
diseases along with some identified and rectified research gaps
to achieve transparency in the plant disease detection before
their symptoms appear clearly.

2. Plant diseases

When plants are disturbed by some agents, it causes an anoma-
lous physiological reaction that disturbs the normal growth and
structure of the plant. Plant disease can be classified into infec-
tious and noninfectious. Infectious diseases are due to patho-
genic organisms such as viroid, mycoplasma, virus, fungus,
nematode, bacterium, or parasitic flowering plant. Infectious
agents spread the disease from one host to another or within
the host. In contrast, the noninfectious plant diseases are due
to adverse growth condition, which includes moisture, tempera-
ture, toxic substance, or mineral deficiency. Plants can be
infected by more than one disease at a time that makes the
disease more complex. The factors that are related to recognize
the plant diseases are the standard growing habit and the
variability in the growth. Pathology is the study of plant diseases
derived from the Greek words pathosdsuffering and
logosddisclosure.
Pathogenesis is a condition in which the pathogen is closely
related to the living host tissue. The stages of pathogenesis are
as follows:
• Inoculation
• Incubation
• Infection
Virulence, a vital behavior of pathogenic organisms, can
destroy the tissues, enzymes, and the cell walls. Saprogenesis,
part of the pathogen's life cycle, grows on the dead host tissue.