PESTS AND DISEASES OF HELLEBORES
As herbaceous plants go, the hellebore family is one of the toughest. They can shrug off most ailments unless they become afflicted by the dreaded Hellebore Leaf Spot. Below is a list of the common problems you are most likely to encounter.
Cause: Aphids are a well known pest insect that can quickly colonise the soft tissue parts of your plant. They damage and weaken the plant by sucking the sap out of pressurised parenchyma cells found just below the leaf's surface.
Symptoms: Clusters of these small insects are readily identifiable, normally at the plants tips or on the underside of their leaves. In severe cases, the infected parts can begin to wither due to the quantity of sap being removed from that area.
Treatment: There are many chemical treatments available including a number of organic, but all of these must be applied at the first signs of infection to achieve the best effect.
For further information click onto:
How to Make a Natural and Organic Insecticide for Aphids
How to Make your Own Organic Pyrethrum Insecticide
Cause: This group of fungi can affects many plants and unfortunately they are not host specific. That means that they are able to cross infect plants from a variety of different host plant families.
Symptoms: These moulds can easily be identified by a white or grey powdery coating that can appears on the leaves, stems or flowers of your plant. You may also see pale yellowish spots forming on the leaves as a further indication. As the infection progresses this coating can spread to envelope the rest of the plant, eventually killing it.
Treatment: There are a number of effective chemical treatments that can be applied here, but infected plants will need fortnightly applications during the Summer - particularly during prolonged dry periods. Sulpur is a popular choice, particularly with organic gardeners although it can damage sensitive plants. A more reliable alternative is to use a general systemic insecticide.
HELLEBORE LEAF SPOT
Cause: This can be an aggressive infection caused by the fungus Coniothyrium hellebori. Unfortunately it only requires damp condition to proliferate.
Symptoms:This fungal infection is easily identified as the leaves become visibly damaged by large, almost circular and concentrically marked, dark brown blotches that can be seen on both sides of the leaves.
Treatment: This is a difficult disease to treat and so the first thing to do on recognizing the symptoms is to remove and destroy all of the infected leaves. In severe cases you may wish to try spraying with a copper fungicide - such as Bordeaux mixture - once every month. This should prevent the infection from getting worse but it is unlikely to cure it.