Rhizoctonia fruit rot, caused by Rhizoctonia solani, is a common disease of tomato wherever it is grown. R. solani is a widespread soil inhabitant and is probably found in most soils in High Plains, living on decaying plant material. The pathogen probably can attack all cultivated crops, but no one strain of R. solani can attack all crops. R. solani can attack tomato roots and stems, but fruit infection occurs when ripe fruit contacts cool to warm, wet soil. Green fruit can occasionally be attacked by R. solani, but ripe fruit is most susceptible. Wounds increase invasion of the fruit by the fungus, but the fungus can also penetrate young, succulent tissue. R. solani is disseminated in contaminated plant material and infested soil. The Rhizoctonia fruit rot pathogen survives between tomato crops on alternate hosts, weeds, and in and on crop debris.
Fruit lesions appear as a brown rot with alternating light- and dark-colored concentric bands. The rot often is firm at first, but often becomes soft and watery as secondary pathogens invade the fruit. Fruit may be infected but symptoms do not develop until fruit is harvested and shipped, causing a brown nest rot. Brown, coarse fungal mycelium is often apparent on fruit under moist conditions.
No biological control strategies have been developed for Rhizoctonia fruit rot.
Prevent fruit from contacting the soil by staking plants and using plastic mulches. Varieties highly susceptible to Rhizoctonia fruit rot should be avoided, especially if plastic mulch is not used.
Certain fungicides reduce fruit rot losses but may not be economical in the High Plains.
Product List for Rhizoctonia Fruit Rot:
Pesticide |
Product per acre |
ApplicationFrequency
|
Remarks |
|
Chlorothalonil and Chlorothalonil Mixtures |
|||
|
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 |
|
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, Rhizoctonia Fruit Rot
Date: 04/01/2007