Search Plant Disease Handbook

Daphne-Twig Blight March 2023 See: Greenhouse Plants, Ornamental- Gray Mold Cause Botrytis cinerea, a fungus. The disease is favored by warm and moist conditions. Can survive in dead plant debris and is ubiquitous in most Pacific Northwest production area ...

Daylily (Hemerocallis spp.)-Daylily Rust March 2023 Cause The fungus Puccinia hemerocallidis is an exotic rust native to Asia. This pathogen was detected in daylily (Hemerocallis spp.) nursery stock in the southeast in 2000. It has since spread to many ot ...

Delphinium-Black Leaf Spot March 2023 Cause The bacterium Pseudomonas syringae pv. delphinii has been found on Delphinium by the OSU Plant Clinic. Another bacterium, Pseudomonas chicorii, has similar symptoms but has not been reported from the Pacific Nor ...

Delphinium-Botrytis Blight March 2023 See: Greenhouse Plants, Ornamental- Gray Mold Chemical control Best when used on delphinium along with cultural controls. Tank-mix and/or alternate products from different groups with different modes of action to prev ...

Delphinium-Damping-off March 2023 Cause Damping-off can develop on the seed, radicle, hypocotyl, epicotyl, or stem of an emerged seedling. Damping-off is caused by the organisms Pythium spp., Rhizoctonia solani, and/or Fusarium spp. These organisms can al ...

Delphinium-Leaf Spot and Crown Rot March 2023 Cause The fungus Calophoma aquilegiicola (formerly Diplodina delphinii) has been found by the OSU Plant Clinic. The fungus overwinters on host debris and in the crown of living plants. The disease is favored b ...

Delphinium-Powdery Mildew March 2023 Cause Several fungi such as Erysiphe spp. and Podosphaera spp. can cause powdery mildew but only Erysiphe polygoni and Golovinomyces cichoracearum (formerly Erysiphe cichoracearum) have been reported from the PNW. Coni ...

Delphinium-Pythium Crown and Root Rot March 2023 See: Greenhouse Plants, Ornamental- Pythium Seed Rot, Damping-off, and Root Rot Cause Several species of Pythium can rot Delphinium species as well as many other bedding and garden plants. It has been found ...

Delphinium-Stem Canker March 2023 Cause Fusarium oxysporum f. sp. delphinii has been reported on delphinium from Washington. The fungus usually infects the roots or stems through wounds. Macroconidia and microconidia are formed in sporodochia on stems and ...

Delphinium-Stem Rot March 2023 Cause The fungus Sclerotinia sclerotiorum has an extremely wide host range infecting 383 plant species in at least 64 families. The disease develops in cool, wet conditions and is more prevalent when plants form a complete, ...