Plant Disease Management Handbook

See:

Onion (Allium cepa) - Purple Blotch

See:

Seed Crop, Crucifers (Brassica, Eruca, and Raphanus spp.) - White Rust

Cause A fungus-like microorganism, Peronospora trifoliorum, which overwinters on the plant and on diseased crop residue. Cool, moist conditions promote the development of downy mildew. It seldom seriously reduces seed production, and is rarely a problem in forage fields. The disease has been reported on crimson, red, and white clover in other regions of the US and the OSU Plant Clinic in Corvallis received a crimson clover sample with downy mildew in 2024.

Cause A bacterium, Pseudomonas syringae, causes bacterial leaf spot or blight of clover. The bacterium overwinters on diseased crop residue. Infections in the field can be spread by splashing rain or irrigation water, and on contaminated tools or equipment. Cool, moist conditions favor disease, including rainy weather, excessive irrigation, or extended periods of dews.

Cause A fungus, Stagonosporopsis caricae (syns. Stagonosporopsis citrulli, Stagonosporopsis cucurbitacearum, Didymella bryoniae, Phoma cucurbitacearum), which overwinters in associaton with infected crop debris for at least two years. This fungus can also be seedborne. Numerous other cucurbits are affected, including watermelon, cucumber, squash, and pumpkin.

See:

Seed Crop, Crucifers (Brassica, Eruca, and Raphanus spp.) - White Rust

See:

Radish (Raphanus sativus) - White Rust

Seed Crop, Crucifers (Brassica, Eruca, and Raphanus spp.) - White Rust

See:

Radish (Raphanus sativus) - White Rust

Seed Crop, Crucifers (Brassica, Eruca, and Raphanus spp.) - White Rust

See:

Radish (Raphanus sativus) - White Rust

Seed Crop, Crucifers (Brassica, Eruca, and Raphanus spp.) - White Rust

See:

Seed Crop, Crucifers (Brassica, Eruca, and Raphanus spp.) - White Rust