Many pathogens can cause tomato fruit rots, including Botrytis cinerea, Alternaria solani and A. alternata, Phytophthora spp., Pythium spp., Colletotrichum spp., and Rhizoctonia solani, among others. These pathogens can cause minor to severe damage to fruit depending on environmental conditions and cultural practices. Fruit rot can occur when temperatures are cool to warm, free moisture is present, and humidity is high. Fruit rot pathogens have varied life cycles, but generally survive between tomato in and on crop debris and culls, as pathogens on weeds and other crops, as a saprophyte on decaying organic matter in soil, in the soil as dormant resting structures, and occasionally in contaminated seed. Spores of these pathogens are readily disseminated within and between tomato fields by wind and splashing rain and irrigation water.
Disease symptoms vary depending on the pathogen attacking the fruit, but may include soft, watery decay, brown to black sunken lesions with concentric rings, with or without white cottony mycelium growth. Damage to tomato varies depending on the specific fruit rot pathogen, environmental conditions, and disease management strategies, but fruit rots can be very devastating. Yield and quality losses can approach 100% under certain conditions.
No biological control strategies have been developed for fruit rots.
No single strategy is effective for fruit rot management, but fruit rots can be successfully managed with an integrated strategy. Integrated management of tomato fruit rots begins with planting seed and transplants free of fruit rot pathogens. Adhere to a three-year or longer crop rotation to non-hosts to reduce inoculum surviving in the field. Eliminate crop debris, culls, volunteers, and weeds that can serve as alternate hosts for fruit rot pathogens. Provide adequate, but not excessive, fertilizer to promote vigorous plant growth. Ensure the ratio of calcium to phosphorous in the soil is at least 2:1. Plant resistant varieties where available. Promote rapid leaf drying and air movement within the field by avoiding overhead irrigation and dense plantings. Time irrigations to allow foliage to dry before dusk to avoid prolonged periods of leaf wetness. Orientating rows parallel to the prevailing wind direction can help reduce humidity within the canopy and avoid conditions favorable to fruit rot pathogens.
Chemical controls are most effective when combined with as many cultural control strategies as possible. Strains of some fruit rot pathogens are resistant to some common fungicides such as Ridomil. Alternative chemical and cultural controls are necessary for effective disease control where resistant strains are present. In general, regular fungicide spray programs for foliar pathogens will often suppress the fruit rots that these pathogens cause as well.
Product List for Fruit Rots:
|
Pesticide |
Product per acre |
Application Frequency |
Remarks |
|
Boscalid |
|||
|
Endura |
2.5-3.5 oz |
7-14 days |
Maximum of 21 oz or 6 applications per season; do not make more than 2 consecutive Endura applications before rotating to a fungicide with a different mode of action; 0 day PHI |
|
Captan |
|||
|
Captan 4F |
4 pt |
5-7 days |
4 day REI |
|
Captan 50 |
2 lb |
5-7 days |
4 day REI |
|
Chlorothalonil and Chlorothaloni/Mefenoxam |
|||
|
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 |
|
EBDC/Zoxamide |
|||
|
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 |
|
Mefenoxam |
|||
|
Ridomil Gold/Copper |
1 pack/per 2.5 acres |
5-14 days |
Make 3 total sprays; 14 day PHI |
|
Ridomil Gold EC |
1-2 pts |
|
Broadcast or banded at planting; Maximum of three injections by drip irrigation; maximum of three pints per season; 7 day PHI |
|
Ridomil Gold GR |
20 lbs |
|
Band (7”) or broadcast and incorporate with 0.5 to 1” of irrigation water; a second application can be made; Maximum of 40 pounds per season; 7 day PHI |
|
Strobilurin and Strobilurin Mixtures |
|||
|
Cabrio |
8-12 oz |
7-21 days |
Maximum of 6 applications or 96 oz per season; Do not make more than 2 applications of Cabrio before alternating with a fungicide with a different mode of action; 0 day PHI |
|
Flint |
2-3 oz |
7-10 days |
Maximum of 4 applications or 16 ounces per season; Rotate with fungicides with a different mode of action such as Maneb, Endura, or copper-containing products; 3 day PHI |
|
Quadris |
5-6.2 oz |
5-14 days |
Maximum of 5 applications or 1.15 quarts per season; Alternate Quadris with fungicides with different modes of action; 0 day PHI |
|
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 |
|
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. |
|||
Categories: Eggplant, Pepper, Tomato, Disease, Fruit Rots
Date: 04/01/2007