Delphinium Black Blotch – Pseudomonas syringae pv. delphinii

Delphinium black blotch Common name Delphinium black blotch Causal agent It is a bacterial disease that attacks the delphinium species and affects the quality of the plants. Scientific name Pseudomonas syringae pv. delphinii Symptoms & Signs It shows irregular brown-black spots on the upper part of the leaves, which fuse together to cover the entire leaf. The stems and branches also show brownish lesions, sometimes causing the death of the plant. Transmission It is transmitted by means of water, wind, insects, and infected tools. Cool, wet weather conditions favor the growth and spread of this bacteria. Time of concern Easly spring to late summer Common hosts Delphinium alabamicum Delphinium altissimum Delphinium alpestre