🦠Plant Disease Info

What is a disease?

A disorder of structure or function in a person, animal, or plant, typically exhibiting signs
of infection and impairing quality of living.

What are the four main pathogens that cause plant diseases?

Fungus, bacteria, virus,
and nematode.

What percentage of plant diseases are caused by fungi?

Roughly 80-85%.

What are the characteristics of fungi?

Fungi belong to the fungi kingdom, are eukaryotic, and
can be single-celled or multicelled organisms.

How do pathogenic fungi enter plants?

Through cuticles or wounds, invading the vascular
system.

What are common symptoms caused by fungi?

Rust, mildews (downy & powdery), lesions,
and wilting.

What defines bacteria?

Bacteria belong to the bacterial kingdom, are prokaryotic, and can be single-celled.

What is the role of saprophytic bacteria?

They feed on dead organic matter and are mostly
beneficial.

How do pathogenic bacteria spread within plants?

Through natural openings, insects, and
machinery, often causing chlorosis or water-soaking.

What is a virus?

A protein that contains DNA, cannot reproduce without a host cell, and is considered an obligate parasite.

What are common symptoms of viral infections in plants?

Mosaic patterns, dwarfing,
yellowing or reddening of foliage.

What are nematodes?

Wormlike organisms belonging to the animal kingdom, not classified as diseases but can cause damage to plants.

How do nematodes affect plants?

They leave hollow stylet punctures on host cells, causing
symptoms like galls, excessive branching, and poor root systems.

How do diseases enter a host organism?

Through access points like stomata, flowers, insect damage, and machinery.

Do plants have an immune system?

Yes, plants have simple immune systems that can quarantine parts of themselves and produce chemical compounds to combat pathogens.

What is salicylic acid in plants?

A plant-produced chemical similar to aspirin that helps combat pathogen progression.

What conditions are necessary for a disease to occur?

A pathogen, a host, and an
environment to incubate.

What is the role of cell walls in plant immunity?

They provide structure and shield against
common strains of disease.

What are the methods to prevent fungal infections in plants?

Tillage and row
spacing.

What are the methods to prevent bacterial infections in plants?

Seed treatment and levels of defense.

What are the methods to prevent viral infections in plants?

Using resistant varieties, sanitizing machinery, and practicing crop rotation.

What are the methods to prevent nematode infections in plants?

Crop rotation, seed treatments, and managing soil moisture.

What is the life cycle duration of nematodes under good conditions?

3-4 weeks.

What are the carriers for fungal pathogens?

Wind, water, and insects.

What are the three factors required for a disease to occur?

A susceptible host, a
pathogen, and a conducive environment.

How can diseases be transmitted from one plant to another?

Through a casual
agent, which can be activated by environmental factors.

What are the stages a disease must go through?

Inoculation, incubation, and infection.

What is inoculation in the context of plant disease?

The presentation of the pathogen at
a part of the plant where infection can occur.

What factors influence the incubation stage of a plant disease?

Proper temperature
and moisture.

What are common symptoms of plant disease?

Cell death, stunting, chlorosis, and tissue
overdevelopment.

What is a non-infectious plant disease?

A disease that cannot be transmitted from a diseased plant to a healthy one.

What environmental conditions can lead to non-infectious diseases?

Cool, wet conditions can lead to seed rot; nutrient deficiencies can cause blank spots.

What are the three main strategies for disease control?

Exclusion, eradication, and
protection.

What factors should be considered when diagnosing crop problems?

Crop
history, chemistries applied, field yields, and management practices.

What does examining plants for disease involve?

Looking at roots, stems, leaves, and the
internal plant makeup.

What is damping off in corn diseases?

A disease that kills or injures seedlings, favoring cool
and wet conditions.

What pathogens are responsible for damping off?

Pythium, Rhizoctonia, and Fusarium.

What is stalk rot?

A disease affecting the stalk, typically setting in during the late season.

What are the symptoms of Gibberella stalk rot?

Black mold on the outside of the stalk and
red pith near the infection.

What is common corn smut?

A soil-borne fungus that causes galls on corn plants.

What are teliospores in relation to common corn smut?

Spores that overwinter in old
crop residue and soil, remaining viable for 2-3 years.

What is Goss's Bacterial Wilt?

A bacterial disease affecting corn, characterized by dried ooze and
water-marked freckles.

What are corn nematodes and their impact?

Up to 50 species that cause stubby roots and
yield loss in corn.

How can high nematode populations be identified?

By observing stunted plants, yellow-
ing, uneven tasseling, and root necrosis.

What methods can be used to control nematodes?

Sanitizing equipment, using nematicides, and crop rotation.

What is the role of environmental factors in plant disease symptoms?

They can
affect the appearance and progression of symptoms over time.

What is the significance of plant age in disease impact?

The age of the plant can
influence how much of the plant is affected by the disease.

What is the importance of crop rotation in disease management?

It helps to break
the life cycle of pathogens and reduce disease incidence.

What is the role of fungicides in disease control?

They are used to treat or prevent fungal
infections in crops.

What are the effects of nutrient deficiencies on plant health?

They can lead to
symptoms that mimic disease, such as stunted growth and chlorosis.

What is the impact of weather on plant disease development?

Weather extremes
can create conditions that favor disease outbreaks.

How can crop management practices affect disease prevalence?

Practices like
tillage and fertility management can influence plant health and disease resistance.

What is the significance of examining several plants for disease diagnosis?

It
helps to distinguish between genetic attributes and actual disease symptoms.