How To Recognize Delphinium Diseases?

2024 Author: Gavin MacAdam | [email protected]. Last modified: 2023-12-16 13:38

The luxurious delphinium often falls prey to a wide variety of viral, fungal and bacterial ailments. At the same time, almost always the manifestation of this or that misfortune is in direct connection with weather conditions. Underdeveloped plants are most susceptible to damage, so if the rules of agricultural technology were ignored when growing delphiniums, the risk of their infection increases significantly. It's time to figure out how various diseases manifest themselves on these magnificent flowers

Bacterial wilting

The development of this dangerous ailment is equally favored by both too humid and very hot weather. The lower leaves of delphiniums turn yellow, and brownish or black spots with strongly softened tissues are formed on their stems. Gradually, these spots merge with each other, and all the lower parts of the stems turn black. If you try to split the stems, then a foul-smelling slimy mass will be found inside them. To prevent the development of such an infection, the seeds are kept for about twenty-five to thirty minutes in water heated to fifty degrees before sowing.

Black leaf spot

The most favorable conditions for the development of black spot are created by humid and rather cool weather. On the leaves of the delphinium, black spots of a wide variety of sizes and shapes, painted on the lower sides in brownish tones, gradually begin to appear. As a rule, the ill-fated disease begins to develop on the lower leaves, gradually spreading upward. This happens until nondescript blackened stems remain from the beautiful delphiniums.

The bacteria that cause this attack overwinter either under fallen leaves or in the soil, so in the fall it is necessary to thoroughly dig up the soil and remove all debris accumulated on it from the site.

Fusarium

This attack, attacking beautiful delphiniums in hot summer, almost always overtakes weakly rooted and young flowers. Watery brownish spots appear on the affected stems, and the harmful fungus slowly begins to move towards the root collars. And as soon as it penetrates into the tissue of the roots, the plants immediately wither. The death of plants affected by this disease usually occurs after four to five days.

If spots suddenly appear on the stems, it is recommended to cut them off - this will prevent the penetration of the fungus to the root collars. As a rule, the spread of destructive fungal spores occurs through rainwater or wind. In addition, the infection can be seed-borne. The pathogen easily persists in the soil for several years, so it is better not to plant delphiniums in infected areas.

Powdery mildew

On the surfaces of the leaves of the delphinium, a characteristic bloom of a grayish-white color appears. And after some time, the leaves affected by the fungus turn brown or turn brown.

To prevent the development of such an infection, it is necessary to pick dying leaves from delphiniums in a timely manner, thin out flower bushes and water them well when dry weather is established. If the disease has already overtaken the beautiful delphiniums, they are sprayed with either an infusion of cow dung or a 1% suspension of colloidal sulfur.

It is noteworthy that delphiniums endowed with smooth leaves are much less susceptible to powdery mildew than their comrades with hairy leaves.

Downy mildew

This ailment manifests itself on the delphinium in the fall, especially if prolonged rainy weather sets in. On the undersides of the leaves, you can see a powdery whitish bloom. The most susceptible to this scourge are those delphiniums that grow in damp and low areas, as well as in thickened plantings. Timely thinning of flower bushes and excellent soil drainage will help prevent the development of a harmful infection. Also, for preventive purposes, delphiniums are sprayed with Bordeaux liquid (0.5%).