Honey bees are essential for successful cucumber pollination and production. At least one strong colony per acre is needed to ensure adequate bee activity. Colonies should be placed in the field after the onset of significant flowering. All cucurbits are susceptible, and depending on the weather, stem and leafspotting may occur on young plants, especially in late plantings. Anthracnose is common and is caused by the seedborne fungus Colletotrichum lagenarium.
Most cucurbits are susceptible.
Most commercial cucumber varieties have some resistance. Depending on weather, leaf and fruit spotting may occur on young plants, especially in late plantings. Angular Leafspot is infrequent and is caused by the seed-borne bacterium Pseudomonas lachrymans which can also affect squash and pumpkins. Warm, wet weather may cause stem and leaf spots in midseason. Powdery Mildew is caused by two air-borne fungi Erysiphe cichoracearum and Sphaerotheca fulginea, but is rarely seen since most commercial cucumbers have excellent resistance.