Disease Management in the Vegetable Garden

Disease
Management in the
Vegetable Garden

How Integrated Pest
Management can save your

plants

Disease…

’ Can reduce yield
’ Reduces flavor and quality
’ Limits shelf life

What causes disease?

’ Fungi
’ Bacteria
’ Virus
’ Abiotics
’ Humans?

Disease Triangle

Fungi

’ Most important
problem in gardens

’ Spread by spores

’ Cause rot, powdery
mildew, leaf spots

Fungal Forms

Smut Rust
Rhizoctonia

Bacteria

’ More of a problem
for fruit trees

’ Spreads in
splashing water

’ Dissolve tissue,
leaves it greasy-
looking, smelly

’ Often causes wilt

Pseudomonas

Bacteria

’ Need opening into
plant – either
through natural
(flowers, etc.) or
wounds

Virus

’ Can cause
bizarre
coloration, vein
clearing,streakin
g, or twisted
growth

’ Must be
vectored

’ Can appear in
seed

CucomoVirus

Virus Symptoms

Humans

’ Wrong plant in
wrong place

’ Compaction
’ Herbicide
’ Tobacco

Abiotics

Sunscald ’ Nutrient
deficiencies

’ Heat
’ Water stress
’ Weather

Ozone toxicity

Blossom end rot

Nutrient Deficiency Symptoms

Are the symptoms on the lower leaves or the upper leaves?

Upper leaves Lower leaves

What’s the color pattern? What color are the leaves?

Light green Yellow stripes Yellow Purple
Where is the Phosphorus
Are the plants yellow color? deficiency
spindly?
Yes Leaf tip and Leaf edges
along midvein
Sulfur Deficiency Are the internodes short? Potassium
Yes No Nitrogen deficiency
deficiency
Zinc deficiency Iron deficiency

There is no silver bullet

’ No single cure will control all diseases
in the garden.

Problem avoidance:
several methods should

be used

’ Crop rotation
’ Plant resistant varieties
’ Use certified seed
’ Site preparation
’ Good cultural practices

What are some
characteristics of a

resistant variety?

Plant Resistant
Varieties

’ Bred to be less
affected by
diseases

’ Often are labeled

– VFFN

’ Heirlooms less
likely to be resistant

Use Certified Seed or
Plants

’ Some viruses and
fungi are seed
borne

’ Don’t plant a
problem!

Soil Preparation

’ What does soil
have to do with
disease
prevention?

Have Good Culture

’ Control weeds
’ Plant at right time
’ Give plants room
’ Mulch
’ Use drip irrigation
’ Don’t work garden

when plants are wet

Sprays

’ Copper based fungicides
’ Bordeaux Mix