Contaminated planting material and associated soils can introduce several major mint diseases, insects, nematodes, and weeds. Among the major diseases are verticillium wilt, mint rust and stem and stolon diseases, such as mint stolon decay and black stem. Insect pests such as mint root borer and mint flea beetle complete their life cycle in underground plant parts. Cutworms, root weevils, and symphylans also are transported with infected roots and soil. Nematodes, such as the root lesion nematode, the Northern root knot nematode and the needle nematode, complete their developmint in the soil or roots of mint and are easily spread from field to field in infected planting material. The best way to avoid nematode problems is to plant certified mint roots into nematode-free fields. Annual and perennial weeds also can be introduced with root plantings as seeds or as weed plant parts such as rhizomes. Weeds that spread by underground roots and rhizomes include; Canadian thistle, field bindweed, and quack grass. Weed control by tillage is limited and often not practiced because it spreads verticillium wilt. Prevention through the use of clean mint roots is a key strategy for pest management in mint.

The adoption of a certification program for mint is an effective method for preventing the introduction of pests and disease. Industry and state programs have been developed to provide certified planting material to mint growers. The Mint Industry Research Council and state mint grower associations can provide an up-to-date list of sources for certified mint planting material.