Diseases And Pests Of Roses

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Diseases And Pests Of Roses
Diseases And Pests Of Roses
Video: Diseases And Pests Of Roses
Video: Insect Pests of Roses 2023, February
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I must say that many diseases primarily affect young and weakened plants, the plants for which are not carefully and not properly looked after.

Powdery mildew

powdery mildew
powdery mildew

The causative agent is fungi of the genus Oidium, Sphaeroteca, Microsphaera, etc. - a common fungal disease. This disease not only weakens and depresses the plant, but also often leads to death. It appears in a characteristic white (like flour) bloom on the leaves, mainly on the upper side, then on the stems and buds. A poorly ventilated room, excess fertilization and overcrowding of plants contribute to the disease.

Control measures. Remove affected shoots, leaves, buds from diseased plants. If the disease has spread strongly, covered all the leaves, it is easier to cut off all the shoots at the root, leaving 5 cm stumps.After that, be sure to spray everything that remains after pruning with Topaz, spray the ground and the walls of the pot too. In addition to topaz, other drugs can be used, for example, foundationazol. Dilute the fungicides according to the instructions and be sure to re-spray.

Downy mildew

The causative agent is fungi of the genus Peronospora, Plasmoparma, etc. - easy to confuse with a previous illness. The difference is that with downy mildew, the underside of the leaf is mainly covered with a white fluffy bloom from fungal spores. And on the upper side of the leaves, you can see light or purple spots. Downy mildew spreads primarily on wet leaves.

Control measures. In diseased plants, the affected shoots, leaves, buds are removed, the plant is treated with a fungicide, and each time it is better to treat the plants with different fungicides in order to exclude the emergence of resistance (addiction) of fungi to the drug. Usually 2-3 treatments are sufficient.

spotted roses
spotted roses

Rose spots

It is more likely not one disease, but a group with similar symptoms, pathogens, both fungi and bacteria. At the same time, spots appear on the leaves of the plant, which, with the spread of the disease, grow in size, merge and affect the entire leaf as a whole. The spots can be dry or wet, along the edge or over the entire surface of the leaf. In roses, this disease often manifests itself in the second half of the growing season, this is facilitated by the increased humidity of the air and soil, thickened crown, poor ventilation of the room, dense caked (not loose soil in a pot.

Control measures. Removal of diseased leaves and shoots. Spraying with any copper-containing preparations (oxyhom, home, copper sulfate, Bordeaux liquid) or sulfur preparations (colloidal sulfur, thiovit-jet, mancozeb, tiram), regulation of watering and stopping spraying with plain water until recovery. Usually 2-3 treatments are required (including soil surface). Note that all fungicides containing copper will leave blue or blue streaks on the leaves.

rust of roses
rust of roses

Rust of roses

In this disease, pustules are formed on the back of the leaf, which can be completely different colors - from red or orange to dark brown, they protrude above the leaf like warts or papillomas, always round in shape. Brown spots appear on the upper side of the leaf over time.

Control measures. Remove all suspicious leaves as early as possible. Spraying with fungicides specially formulated to control rust fungi such as topaz. Rose rust is promoted by keeping in a poorly ventilated room, with high humidity and high air temperatures.

Rose pests

Rose aphid

A pest that affects both leaves and buds. Shoots and leaves curl, become covered with sticky secretions of aphids, on which a sooty mushroom settles. It all looks like the plant has dandruff or flakes, flowers and buds are deformed. The damaged parts are discolored, the leaves curl, turn yellow and fall off. The plant is severely depressed and stops normal development. The buds do not open, the flowers are contaminated with secretions. Aphids are especially dangerous in spring, affecting the tips of young shoots. At home, roses can become infected through garden soil or from store plants.

Control measures. Remove all affected shoots, wash the foliage 2-3 times with soapy water. Then spray and water the bushes with a solution of Aktara. If the lesion is very strong, for example, from cuttings cut in a garden where aphids are rampant, then it is better to soak in a solution of actellik (20 drops per 1 liter of water).

spider mite on a rose
spider mite on a rose

Spider mite

Previously, it was believed that the appearance of mites is facilitated by too dry and warm air in the room, however, this opinion has been debunked by many years of experience: roses are affected by mites in any climate, at any humidity, they simply have an extremely high susceptibility. But in dry and hot conditions, ticks multiply many times faster than in cool and high humidity, literally in 3 days they can damage a whole rose bush in a pot. Ticks hide on the underside of the leaf, in the axils of the shoots and buds. The surface of the damaged leaves is first covered with pale dots - the places where the cell sap is sucked out, but later they increase, continuous whitish spots are formed, the leaves curl and fall off.

If you are not sure if there is a mite on the roses, take a magnifying glass and inspect the back of the leaf - you can see the skins from mite molting (whitish husk), or the mites themselves: they can be almost invisible - gray, or yellow-red, brick-colored or dark brown (variety of many species).

Control measures. Against ticks, drugs of the class of insectoacaricides or acaricides are used - actelik, neoron, fitoverm, apollo, vermitek, Etisso Blattlaus-Sticks (stick into the ground) and others. Since ticks are highly resistant (resistant to chemistry with each new generation), the preparations must be changed or alternated. If you buy a rose in a store, bring cuttings from the garden, root a rose from a cut (bouquet), the probability that it has a tick is about 90%, if not more. Therefore, prevention is simply mandatory: spray the leaves very carefully from all sides with phytoverm. Another prevention method is regular hot showers. Roses tolerate contact with hot water at 53-55 ° C very well. Under strong pressure from the shower, water washes away ticks, egg-laying, cobwebs. If you carry out 4-5 procedures in a row, you can get rid of ticks without chemistry.Learn more about ticks.

Thrips

spider mite on a rose
spider mite on a rose

This pest comes to us, most often, with garden flowers and bouquets. And high temperature and low air humidity contribute to their faster reproduction. At home, thrips can harm roses all year round, but especially in the spring and summer.

Thrips damage leaves, flower buds. As a result of their activity, silvery spots similar to small shading appear on the upper side of the leaves. In case of mass infestation, the entire surface of the leaf becomes whitish and discolored, and in addition, black shiny excrement of pests is visible.

Control measures. The plant should be washed with green or tar soap from the secretions of the pest, and the most damaged leaves should be removed. Then spray and pour with a solution of the drug Aktara or Confidor - these systemic drugs are most effective against thrips.

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