Gray mold on hydrangea: useful information to recognize and treatgray moldofhydrangea. There gray mold is a disease that affects the leaves and flowers ofhydrangeacausing it to rot with the development of gray mold.
There gray moldit is caused by the fungusBotrytis cinerea, parasite that attacks many varieties of plants. It causes damage to ornamental plants but also of economic interest such as vines by attacking the bunches of grapes. Thegray rotorgray mold, can cause allergies.
The characteristic colorash grayit is dictated by the sporata (mass of spores) typical of Botrytis cinerea. The spores are the means of reproduction of the fungus, therefore, in case of manual removal of the diseased parts it is recommended their complete elimination.
Only in the presence of very favorable conditions for the propagation of the fungus we recommend using fungicides. It is good to remember that this type of fungus adapts very well to fungicides developing, in a short time, a strong resistance; given these characteristics, if the infestation is mild, it is advisable not to intervene with chemical treatments and to simply remove the part affected by the gray rot. On the contrary, in case of heavy infestations on intensive cultivation of hydrangea, it is recommended to take advantage of the biological control which is less expensive and more effective than treatments with fungicides. If there are a couple of plants affected by gray mold, you can proceed with the use of fungicides even in the case of heavy infestations.
Theregray moldit develops in the presence of persistent conditions of environmental humidity. The fungus responsible for thegray moldit manages to damage the plant tissues causing a process of rotting with the development of the spore. As stated, onhydrangeait is not always appropriate to intervene against thegray moldbut whoever wishes to proceed with the treatment can nevertheless intervene with tebuconazole-4.35 or with fenexamid-42.74 at the doses indicated on the label.
These are systemic fungicides used for curative use. They can be applied in all stages of development of thehydrangea. Tebuconazole enriched formulations are commercially availablepotassium phosphitesto increase the plant's resistance to fungal diseases.
In case of attack it is good to intervene promptly by eliminating all the moldy parts and spraying the plants with some Bordeaux mixture: the treatment should be repeated approximately every 10 days until the problem is completely resolved.
Bordeaux mixture is a widely used remedy also in biological agriculture for this reason it can be found in any agricultural consortium. Those who prefer to buy and sell online can buy a one kg bag of Bordeaux mixture (wettable powder) at the price of 10.90 euros with free shipping. For all information, please refer to product sheets: Bordeaux mixture.
Who seeksremediesmore specific can experience theantibotritis. There are several products against botrytis available on the market. For some it is necessary to have a license (they are pesticides in all respects), while inThis Pageyou can find the antibotritis more widespread on the market and easier to access.
Diseases of hydrangea
There gray moldit is not the only disease that can affect thehydrangea, indeed, the attack of the Botrytis cinerea fungus on hydrangea (responsible forgray mold) is a relatively unusual phenomenon. Other fungal diseases that can attack hydrangea are powdery mildew (caused by the fungusErysiphe polygoni), root rot (responsible is the Pythium spp fungus), hydrangea rust (Pucciniastrum hydrangeae) and southern rust (the responsible fungi are Athelia rolfsii and Sclerotium rolfsii). L'hydrangeait can be attacked by a third type of rust, that of bacterial origin caused by the parasite Pseudomonas solanacearum. For all information, please refer to the article dedicated toDiseases of the Hydrangea.
How to prevent hydrangea gray mold
For preventive use, we do not recommend the use of the fungicides mentioned above because they can give rise to resistant infestations. Good prevention can be done by watering the plant more carefully and trying to keep the humidity levels in the garden low.
Good garden maintenance will protect the hydrangea and other plants from attack by parasites. Water thehydrangeain the early morning avoiding wetting foliage or flowers, irrigate directly at the base of the plant. Remember to do a good pruning of the hydrangea and to follow all the precautions already described in the articleHow to cure hydrangea.