Plant Diagnostics

Thielaviopsis rot (herbaceous-root, stem or crown) - Thielaviopsis basicola (H)

Damage

Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.

Cultural Controls

Disease development is greatly reduced at pH 5.5 or below and is suppressed at temperatures above 72F. Use pathogen-free plants, sterile containers, clean growing areas and pasteurized growing media. Rogue severely infected plants. Provide crops with good drainage and proper irrigation. Use lowest rate of fertilizer consistent with good plant growth and minimize plant stress. Fungicide drenches can be used to protect very susceptible plants from infection.

Chemical Controls

Etridiazole+Thiophanate-methyl
Signal Word: Danger
Pesticide Class: Protectant, Systemic-upward only
Fludioxonil
Signal Word: Caution
Pesticide Class: Protectant
Fludioxonil+Mefenoxam
Signal Word: Caution
Pesticide Class: Protectant, Systemic-upward only
Iprodione+Thiophanate-methyl
Signal Word: Caution
Pesticide Class: Local Protectant, Systemic-upward only
Thiophanate-methyl
Signal Word: Caution
Pesticide Class: Systemic-upward only
Triflumizole
Signal Word: Caution
Pesticide Class: Systemic-upward only

Locations Affected

leaves, roots, stem

Plant Environment

greenhouse, outdoors

Scouting Season:

January - Early , January - Mid , January - Late , February - Early , February - Mid , February - Late , March - Early , March - Mid , March - Late , April - Early , April - Mid , April - Late , May - Early , May - Mid , May - Late , June - Early , June - Mid , June - Late , July - Early , July - Mid , July - Late , August - Early , August - Mid , August - Late , September - Early , September - Mid , September - Late , October - Early , October - Mid , October - Late , November - Early , November - Mid , November - Late , December - Early , December - Mid , December - Late

Plants Affected


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