Cladosporium leaf mold is a disease of tomato caused by the fungus Fulvia fulva (syn. Cladosporium fulvum). The disease is primarily a problem on greenhouse-grown tomatoes, but can occur in the field when humidity is high. Fungal spores germinate under high humidity (85% or greater) and cool to warm temperatures (40 to 90ºF), but disease rarely occurs below 50ºF. Wind, splashing irrigation water and rain, workers, tools, and insects readily disseminate spores. Contaminated seed can also initiate epidemics. The pathogen survives between tomato crops in and on crop residues, and in the soil as spores (conidia) or dormant resting structures (sclerotia).
Leaf mold is most damaging to greenhouse-grown tomatoes, but can occur occasionally on field-grown tomatoes in the High Plains. Disease symptoms are usually limited to foliage, and first appear on the upper sides of older leaves as pale green or yellow spots. Leaf spots have irregular borders, but when infection is severe these spot coalesce and kill large areas of the foliage. The upper surface of affected leaves turns an olive green with more intense color near the center of lesions. Leaves eventually curl, wither, and may drop from the plant. Blossoms, stems, and fruit can be attacked by F. fulva. Affected fruit has a black, leathery rot on the stem end with an irregular margin.
No biological control strategies have been developed for leaf mold.
Plant only high quality seed free from the leaf mold pathogen. Hot water treatment can reduce seed contamination, but can reduce germination. Eliminate crop debris and culls by deep tillage soon after harvest to reduce pathogen survival. Promote rapid drying of leaf foliage by avoiding overhead irrigation and dense plantings. Planting parallel to the prevailing wind direction can hasten leaf drying and reduce leaf mold severity. In greenhouse production, thoroughly sterilize production areas by steam to eliminate F. fulva. Minimize wetting the foliage when irrigating tomatoes. Maintain night temperatures higher than outside temperatures. Resistant varieties are available, but many races of the pathogen exist, and resistance can be overcome quickly by the appearance of new races.
Fungicides control leaf mold, but should be used in combination with as many cultural control strategies as possible to be most effective.
Product List for Cladosporium Leaf Mold:
Pesticide |
Product per acre |
ApplicationFrequency
|
Remarks |
|
Captan |
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|
Captan 4F |
4 pt |
5-7 days |
4 day REI |
|
Captan 50 |
2 lb |
5-7 days |
4 day REI |
|
Chlorothalonil and Chlorothalonil Mixtures |
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|
Bravo 720, Ensign |
1.5-3 pt |
7-14 days |
Do not graze or feed debris to livestock; 7 day PHI |
|
Bravo Ultrex |
1.7-2.2 lb |
7-10 days |
Maximum of 18.3 pounds per season; 0 day PHI |
|
Bravo Weather Stik |
1.5-3.0 pt |
7-10 days |
Maximum of 20 pints per season; 0 day PHI |
|
Echo 720 |
1.5 -3.0 pt |
7-10 days |
Maximum of 2.5 gallons per season; 0 day PHI |
|
Echo 90DF |
1.7-2.5 lb |
7-14days |
Maximum of 16.67 pounds per season; 0 day PHI |
|
Echo Zn |
3-4 pt |
7-10 days |
Maximum of 3.6 gallons per season; 0 day PHI |
|
Ridomil/Bravo |
2-3lbs |
14 days |
Maximum of three applications; 14 day PHI |
|
Copper Fungicides |
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|
Champ Dry Prill |
1.33 lb |
5-7 days |
|
|
Champ Formula 2 |
1.33 pt |
5-7 days |
|
|
Copper-Count-N |
4-6 pt |
7 days |
|
|
Cuprofix Disperss |
2.5-6 lb |
7-10 days |
|
|
Kocide 101 |
1.5-3 lbs |
5-7 days |
|
|
Kocide DF |
1.5-3 lbs |
5-7 days |
|
|
Kocide 4.5LF |
1-2 pts |
5-7 days |
|
|
Nordox |
1.5-2.0 lb |
7-10 days |
|
|
Tri Basic Copper |
2-4 pt |
7-10 days |
1 day PHI |
|
EBDC, Copper/EBDC, and EBDC/Zoxamide |
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|
Cuprofix Disperss MZ |
1.75-4.75 lb |
3-10 days |
Maximum of 21 pounds per season; 5 day PHI |
|
Dithane DF |
2-3 lb |
7-10 days |
Maximum of 8.5 pounds per season; 5 day PHI; use a non-ionic surfactant to improve performance |
|
Gavel 75DF |
1.5-2.0 lb |
7-10 days |
Maximum of 8 applications or 16 pounds per season; 5 day PHI; include a nonionic surfactant to improve performance |
|
Maneb 75 DF |
1.5-2.0 lb |
7-10 days |
Maximum of 8.0 pounds per season; 5 day PHI |
|
Manex 80W |
1.5-2.0 lb |
7-10 days |
Maximum of 7.5 pounds per season; 5 day PHI |
|
Manex |
1.2-2.4 qt |
7-10 days |
Maximum of 16.8 quarts per season; 5 day PHI |
|
ManKocide |
2.5-5.0 lb |
3-10 days |
Maximum of 42.7 pounds per season; 5 day PHI |
|
Manzate |
0.75-1.0 lb |
3-7 days |
Maximum of 8.5 lbs per season; 5 day PHI |
|
Penncozeb 80W |
1.5-2.0 lb |
7-10 days |
Maximum of 7.5 pounds per season; 5 day PHI. |
|
Penncozeb 75DF |
1.5-2.0 lb |
7-10 days |
Maximum of 8.0 pounds per season; 5 day PHI. |
|
Famoxadone/Cymoxanil |
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|
Tanos |
8 oz |
5-7 days |
Rotate and rotato with fungicides with a different mode of action such as chlorothalonil or mancozeb; Maximum of 72 ounces per season; 3 day PHI |
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The information herein is supplied with the understanding that no discrimination is intended and that listing of commercial products, necessary to this guide, implies no endorsement by the authors or the Extension Services of Nebraska, Colorado, Wyoming or Montana. Criticism of products or equipment not listed is neither implied nor intended. Due to constantly changing labels, laws and regulations, the Extension Services can assume no liability for the suggested use of chemicals contained herein. Pesticides must be applied legally complying with all label directions and precautions on the pesticide container and any supplemental labeling and rules of state and federal pesticide regulatory agencies. State rules and regulations and special pesticide use allowances may vary from state to state: contact your State Department of Agriculture for the rules, regulations and allowances applicable in your state and locality. |
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Categories: Eggplant, Pepper, Tomato, Disease, Cladosporium Leaf Mold
Date: 04/01/2007