Tomato Production

• California and Florida make up almost two-thirds 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

• 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 disease-

free transplants; fumigate plant beds and pasteurize the planting medium for container-grown 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 DESCRIPTIONSporangiophores 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:

- 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

• 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 TomatoEarly 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