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Tomato Production
• California and Florida make up almost twothirds of the acres used to grow fresh
tomatoes in the United States.
• Florida remains the leading domestic source
of fresh-market tomatoes.
• Pennsylvania, Ohio, Virginia, New Jersey,
Tennessee, South Carolina, and New York
each plant between 3,000 and 4,500 acres.
Solenaceous Crops Part I
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Fusarium wilt
Bacterial wilt
Late blight
Early blight
DISEASE: Fusarium Wilt
• CROP: Tomato, Potato, Pepper, Eggplant
• PATHOGEN: Fusarium oxysporum f.sp. lycopersic
F. oxysporum f.sp. melongenae (eggplant) and F. oxysporum
f.sp. vasinfectum
• PATHOGEN DESCRIPTION: gungus produces macroconidia,
microconidia, and chlamydospores
DISEASE SYMPTOMS AND
SIGNS:
- yellowing of the lower foliage; yellowing
progresses up the plant and the lower leaves dry
and turn brown.
DISEASE SYMPTOMS AND
SIGNS:
- yellowing of the lower foliage; yellowing
progresses up the plant and the lower leaves dry
and turn brown.
- Plants begin to wilt in the top during the day and
recover at night, but wilting becomes
progressively worse until plants are permanently
wilted.
DISEASE SYMPTOMS AND
SIGNS:
- yellowing of the lower foliage; yellowing
progresses up the plant and the lower leaves dry
and turn brown.
- Plants begin to wilt in the top during the day and
recover at night, but wilting becomes
progressively worse until plants are permanently
wilted.
- vascular browning extends far up the stem and
into large petioles.
CONDITIONS FOR DISEASE
DEVELOPMENT:
- warm weather favors disease development.
- disease is most prevalent on acidic, sandy
soils.
- the pathogen is soilborne and persists many
years in the soil without a host.
- three races are known to exist.
CONTROL MEASURES:
- use resistant cultivars; race 1 and race 1,2 resistant
cultivars are available
- raise soil pH to 6.5 - 7.0
- clean equipment to avoid infesting new fields
- 5 - 7 year rotation reduces losses but does not
eliminate the pathogen
- use of flooded rice in rotation with tomato reduces
disease losses.
CONTROL MEASURES
- use resistant cultivars; some nematode
populations may overcome resistance.
- practice crop rotation; flooded rice greatly
reduces nematode populations.
- use of soil fumigants or soil nematicides are
effective for control.
DISEASE: Bacterial Wilt
CROP: Pepper, Tomato and other crops
PATHOGEN: Ralstonia solanacearum
DISTRIBUTION: Most severe in tropical and
subtropical climates with high rainfall
PATHOGEN DESCRIPTION: Gram-negative
rod
DISEASE SYMPTOMS AND SIGNS:
- occurs in scattered plants or groups of plants
- the initial symptom is wilt of lower leaves (upper
leaves of seedlings) followed a sudden permanent
wilt of the entire plant without yellowing
DISEASE SYMPTOMS AND SIGNS:
DISEASE SYMPTOMS AND SIGNS:
- occurs in scattered plants or groups of plants
- the initial symptom is wilt of lower leaves (upper
leaves of seedlings) followed a sudden permanent
wilt of the entire plant without yellowing
- vascular browning occurs and sometimes cortical
decay is evident near the soil line
- bacterial streaming from vascular elements occurs
when cross sections of the lower stem are
suspended in water.
Bacterial Streaming
CONDITIONS FOR DISEASE
DEVELOPMENT:
- the disease is more severe on tomato, tobacco, potato,
and eggplant, but it can be very damaging to pepper
(occurs on 200+ spp.)
- the bacterium survives in the soil for long periods
- the bacterium gains entry through natural root wounds,
insect or nematode wounds, and cultivation wounds
- high temperature and high soil moisture favor disease
development.
CONTROL MEASURES:
- use pathogen-free seedbeds to produce diseasefree transplants; fumigate plant beds and
pasteurize the planting medium for containergrown plants
- rotate with non-susceptible crops (limited value)
- avoid cultivation that damages roots
- rotate with flooded rice
DISEASE: Late Blight
• CROP: Tomato and Potato
• PATHOGEN: Phytophthora infestans
• Distribution – Temperate and tropical
climates worldwide
SYMPTOMS AND SIGNS:
- all above-ground plant parts may be affected
- leaf lesions are irregular water-soaked patches mat may expand
to encompass large areas of the leaf, white fungal sporulation
may be observed on underneath side; later the lesions dry and
turn brown; blighting of the entire foliage may occur.
- stem lesions are at first irregular water-soaked areas that may
progress and kill sections of stems and petioles or they may
remain superficial and dry out to form dark brown lesions.
- fruit lesions are firm, olive to brown, irregular shaped areas that
cause the fruit to have a rough leathery surface; lesions may
enlarge to encompass the entire fruit.
Late Blight of Potato and Tomato
Late Blight of Potato and Tomato
Late Blight of Potato and Tomato
PATHOGEN DESCRIPTION
Sporangiophores arise through stomata and
produce lemon-shaped hyaline sporangia that
usually release zoospores.
Sporangiophores are hyaline, branched, and
indeterminate, with swellings (knees) at the
point where sporangia were produced.
zoospores
Late Blight of Potato and Tomato
CONDITIONS FOR DISEASE
DEVELOPMENT:
- extended periods of leaf wetness from frequent rain or dew
formation and cool to moderate temperatures are required
for disease development; hot, dry weather stops disease
development
- the fungus persists on tomato and potato plants and in
potato tubers; it does not survive saprophytically
- many strains attack both tomato and potato
- sporangia are produced on infected tissues and are
dispersed by wind and splashing rain
- water on plant surfaces is required for germination and
penetration
Late Blight of Potato and Tomato
Late Blight of Potato and Tomato
CONTROL MEASURES:
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use disease-free transplants or seed
use fungicidal sprays
avoid planting tomatoes near potatoes
host resistance can be overcome
Late Blight of Potato and Tomato
Late Blight of Potato and Tomato
DISEASE: Early Blight
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CROP: Tomato, Potato
PATHOGEN: Alternaria solani
DISTRIBUTION: Worldwide – IL
Tomato - The greatest damage from early blight
spot results from loss of foliage and the exposure
of ripening fruit to sunscald. Plants severely
defoliated in midsummer will not produce good
quality fruit. Such fruit may be small, flabby,
cracked, orange instead of red, and off-flavor.
CONDITIONS FOR DISEASE
DEVELOPMENT:
- the pathogen can be seedborne; it also may persist
in crop debris or on volunteer tomatoes and wild
solanaceous plants.
- extended periods of leaf wetness from frequent
rain, irrigation, or dews favor disease development
- stressed plants are more susceptible, e.g. when
attacked by nematodes and also during fruiting.
Early Blight of Potato and Tomato
DISEASE SYMPTOMS
- small dark circular spots that enlarge into circular
lesions composed of concentric rings.
DISEASE SYMPTOMS
- small dark circular spots that enlarge into circular
lesions composed of concentric rings.
- elliptical lesions occur on stems and petioles
which are drastically weakened at the site of the
lesion.
DISEASE SYMPTOMS
- small dark circular spots that enlarge into circular
lesions composed of concentric rings.
- elliptical lesions occur on stems and petioles
which are drastically weakened at the site of the
lesion.
- fruit rot (green or ripe) - large dark lesions
develop in the calyx area or on the -upper
shoulder.
Early Blight of Tomato
PATHOGEN DESCRIPTION:
• The fungus produces long muriform conidia
borne singly or in chains of two.
CONTROL MEASURES:
- seed treatment
- disease-free transplants
- crop rotations
- avoid planting adjacent overlapping crops
- a fungicide spray program is often necessary
to manage this disease
Early Blight of Potato and Tomato