Preplant

Consider crop rotation for reducing pathogens, harmful nematodes, and problem weeds.

Manage weeds in the previous crop.

• Survey for weeds and keep records (example weed survey form PDF).
• Also survey adjacent areas and crops for problem weeds, host plants of green peach aphid, potato psyllid, and other insects or diseases, and volunteer potatoes.

• Control volunteer potatoes.

Avoid herbicides that leave carry-over residues which may affect potatoes.

Take soil samples to assay for nematodes and soilborne fungal pathogens immediately after harvest of previous crop.

Manage residue from the previous crop.

Manage weeds between crops.

• Irrigate to stimulate weed seed germination after previous crop, before field preparation.
• Cultivate or apply preemergence herbicide as needed to control weeds.

Analyze soil for fertility, physical constraints, and pH, which can affect common scab. Fertilize according to soil analysis results. Providing adequate fertility can help with early blight control.

Watch for wireworms, especially if there is a history of damage. Manage if needed according to the Pest Management Guidelines.

Consider soil fumigation for nematodes and some soilborne pests.

• Nematodes and Corky Ringspot
• Powdery scab
• Sclerotium stem rot
• Verticillium wilt
• Weed control (indirect benefit)

Order seed potatoes of desired cultivar and certification level.

Check seed tubers for tuberborne diseases and frost damage.

• Bacterial diseases (Bacterial ring rot, Soft rot)
• Black dot
• Common scab
• Fusarium dry rot

• Late blight
• Powdery scab
• Rhizoctonia stem and stolon canker (black scurf)
• Silver scurf

Follow proper handling procedures for seed tubers.

Consider seed treatments to reduce disease problems.

• Fusarium seed piece decay
• Rhizoctonia stem and stolon canker (black scurf)
• Silver scurf