Защита роз средствами защиты растений
Viral diseases
Rose mosaic
The virus is transmitted by pollens, seeds, grafting, plant fluid and presumably by threadworms (Longidorus macrosoma) and plant lice.
To protect against this disease, infected rose trees must be removed.
Bacterial diseases
Agrobacterium tumefaciens in rose plants
This pathogen infects the rose tree through the cut surface of the graft. The sick trees are underdeveloped and their leaves become yellowish. On the plants lifted out of the soil soft tissue tumours of various sizes resembling cauliflower can be seen at the cut of the graft.
Fungus-based diseases
Rose mildew
Leaves fallen to the ground in which oospores can survive over the winter form an infection source.
Young leaves growing on the tips of the sprouts will bend towards their backside.
On the upper surface of old leaves yellowish green or purple angular spots bordered by leaf veins can be seen.
Powdery mildew
On the surface of the sprouts we can see some white finely networked coating. The leaves bend and get distorted and the sprout also gets bent and wilt, while the tip of the sprout usually withers. In case of delayed protection the plant may lose its foliage.
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Black spot (Diplocarpon rosae)
In the springtime lower leaves of the rose tree get infected first because conidiums that have survived the winter will deposit on these leaves first. Symptoms can only be seen on the leaves.
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Rose rust
Symptoms may appear on the green parts of the rose, on leaves, sprouts, flower stems and sepals.
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Coniothyrium stem canker
The spotted bark destruction usually starts out from a cut and progresses downward gradually, and if it encircles the crane, the top sprout of the cane will wither.
Trim the infected cane well below the infected part of the rose tree.
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Sphaceloma leaf spot
The symptoms of the disease are similar to those of the black spot, but it will not cause considerable leaf fall.
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Rose affected by botrytis blight
Symptoms
- the bud remains closed and becomes brown (bud death)
- petal patches can be seen on the petals of blooming flowers
- oval lilac red or reddish brown spots appear on green sprouts
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Pests
Big rose plant louse
In addition to losing and bending leaves and propagating of black mould, plant lice also transmit rose mosaic virus , causing irreversible damage to the plant.
Two-spotted spider mite and Onion thrips
These living organisms cannot or can hardly be seen with the naked eye. Their presence can be deduced primarily from the symptoms they cause. They suck fluids from the leaves, petals and buds (the thrips cause damage to the petals of flowers as well). Small spots developed in the place of sucking, which may lead to losing leaves in serious instances, are typical symptoms.
Large rose sawfly (Arge ochropus)
They lay their eggs at the bottom of the petiole. The hatching larvae destroy sprouts by making tunnels.
Rose bug
During blooming scarab beetles (Epicometis hirta) cause damage to a number of plants by eating stamens and pistils of rose flowers, and sometimes they drill themselves into the buds. The rose chafer (Cetonia aurata), which is also polyphag, causes damage to the pistils of rose flowers, not infrequently together with petals. The 1 to 1.5 cm long strongly-haired scarab beetle and the 2 to 3 cm long rose chafer with metallic greenish colour can be detected easily due to their sizes, and an effective protection can usually be achieved against swarming beetles by shaking down and collecting them at dawn.
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