(IPPM) in Vegetables - Vegetableipmasia.org

Resource Manual on IPPM in Vegetable
World Education Philippines, Inc.
PART VIII: COMMON DISEASES OF VEGETABLE CROPS
AND THEIR MANAGEMENT
What is a Disease
· An abnormal condition that injures the plant or causes it to function improperly
(Reissig, W.H. et al, 1986).
· Any disturbance that interferes with the normal structure (e.g., height, tillers, leaves),
function (e.g. reduced vigor, early death), and economic value (e.g. reduced yield,
poor quality produce) of the plant (HOST) is a disease (Philrice, 2002)
A plant disease can be identified or diagnosed through the characteristic or characteristics
manifested by manifestation of diseased condition (symptoms) and the presence of
visible structures (signs) produced by the pathogen.
The causal agent (PATHOGEN) may be either a living (BIOTIC) or nonliving
(ABIOTIC) agent. Biotic agents have the ability to enter and colonize plant parts and
other plants (INFECTIOUS). When disease increases rapidly in a large plant population
over time, a serious outbreak occurs (EPIDEMIC).
A. Disease Triangle
Host
A disease is the result of the
interactions between a pathogen and a
host in a pathogen and a host in a
Pathogen
favorable environment. A disease
generally occurs because the host is
susceptible, the pathogen (causal agent) is virulent, and the environment is conducive for
the disease to grow.
Examples of environmental factors for disease to occur are:
Environment
1. Temperature Bacteria grow rapidly at high temperature. Most insects are also
active and multiply fast in warm temperature.
2. Moisture High moisture content enhances high germination rate of fungal
spores, affects bacteria in entering into plant tissue cells, and increases number
3. Wind wind disperses fungal spores over distance. Strong wind damages plant
tissues, thus, creating entry points for bacteria. Light wind current is favorable for
insects movement.
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