Damping Off of Geranium

Disease Information

Damping Off

Pythium, Rhizoctonia, and Botrytis

Symptomsand damage

Pre-Emergence: Recognized as many random “skips” or empty areas in the plug trays or flats since the fungi attack and kill the developing seedlings before they emerge from the propagation mix;

Post-Emergence: Seedlings topple over and often have a noticeable brown to black lesion at the soil line since the fungi attack and girdle the seedlings after they emerge from the mix; under wet, humid conditions, a gray or off-white webby growth can be seen on the infected seedlings;


a. good sanitation, including use of pasteurized soil or soilless mixes, clean benches, and new or disinfested flats or pots; avoid contamination of mixes and containers during storage

 b. buy fungicide treated seed or use alternative preplant seed treatments c. promote optimum growth and vigor by providing bottom heat to maintain media temperatures of 70-75°F to assist germination

d. avoid overwatering and overfertilizing

e. apply fungicide drenches or sprays of appropriate fungicides such as etriadiazole, etriadiazole + thiophanate methyl, thiophanate methyl, and PCNB


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