Diseases of roses: what are and how to save the plant

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There are several dozen species of insects that feed on plants, settle on them or lay offspring. Pests of roses can not only significantly reduce their protection against diseases, spoil the decorative effect, they can completely destroy the plant if you do not start the fight as soon as possible. It is advisable to fully inspect the bushes more often, noticing the appearance of pests, immediately get rid of them mechanically, for example, rinse with a stream of water, and then develop a strategy for further control.

Video “Pests of roses”

From the video you will learn about insects that harm roses. 

rose aphid

Small, less than 1 mm long insects of green, black or brown colors occupy young shoots, leaves, rosebuds, feeding on their juice. There are winged specimens that fly to other plants, expanding their territory. Shoots under their influence are deformed, deprived of strength stop growing.

If a small number of parasites are noticed, then they must be collected by hand, destroyed, and then the plant should be treated with soapy water or nettle infusion. If you are not an opponent of chemicals, then you can use the Aktara or Etisso systemic insecticide, which is available in a convenient spray form.

Rose leafhopper

If discolored spots appear on the leaves, then they dry out, then you need to look for a yellow insect about 4 mm long on the underside. These are rose leafhoppers that sit along the veins of the leaves, eat away their pulp, drink the juice, and at the slightest movement of the leaf quickly jump down to the ground. They lay their offspring in the bark of shoots; two generations of pests manage to hatch over the summer. Especially a lot of them appear in dry hot weather.

Affected leaves must be removed and destroyed, because larvae may remain there, and the entire plant will have to be treated with insecticides. “Aktara” or other drugs will help to overcome this pest, you just need to process the back of the sheet. It is necessary to carry out two treatments with a break of 10 – 12 days.

The drooling penny, or the omnivorous cicada

On the reverse side of the leaves or in their axils, among the foamy secretions, similar to saliva, the larvae of the omnivorous leafhopper, a gray-yellow insect that feeds on the sap of the plant, are hiding. It is worth turning the leaf over to notice how the larvae crawl out of the foam and run away. To get rid of them, you need to treat roses with chemicals (“Aktellik”), cut off and destroy the affected leaves. Leafhoppers are eaten by ladybugs and lacewings, it would be nice to attract them to the site.

spider mite

This pest often affects indoor and greenhouse roses, but in dry hot weather it can also appear in a garden bed. An inattentive owner can only detect it by the web that braids the leaves and shoots of the plant. A little earlier, small bright spots testify to the appearance of a tiny white tick – first, yellowish dots appear on the leaves, then they grow, a web appears, braiding the branches. It appears with increased dryness of the air and lack of moisture.

To get rid of it, you need to wash the plant, spray it and the area around it with clean water. Of the chemicals used “Fitoverm”.

Screwdrivers

Leafworms feed on leaves, these small grayish-yellow or green caterpillars live in folded leaves. If you do not notice them in time, then the entire rose bush can turn into a sluggish weak plant with twisted and gnawed leaves.

Since the twisted leaves are immediately noticeable, the fight usually starts on time. Damaged leaves must be cut off, the plant should be treated with soapy water or nettle infusion. Good results are shown by the use of the Aktara systemic insecticide.

rose sawflies

A small pale green caterpillar with a reddish head is called a sawfly, it is able to eat all the flesh of the leaf, turning it into a drying lace of veins. They lay their eggs on leaves. If you do not start a fight immediately after discovery, the rose will weaken and stop growing.

Damaged leaves must be removed, it is even better to destroy them, and treat the entire plant with the Iskra or Intavir contact insecticide.

A descending sawfly can bring much more trouble, since its female lays eggs not on the surface of the stem, but inside it. You can notice this only when the shoot suddenly begins to wither and dry out from a certain place, if you break the stem, but a parasite is found inside. The complexity of the struggle also lies in the fact that it is impossible to somehow influence the pest itself and its offspring – because it is hiding inside. Damaged shoots are simply cut to a living place. And for prevention, experts advise in the spring to treat roses with a systemic insecticide, such as Aktara, which is used in the fight against various pests.

Bronzovka and Olenka hairy

These beetles love rose flowers, especially light ones, they eat petals, pistils and stamens. Early in the morning they arrive, sit on the flowers and begin to have breakfast. At this time, they are collected by hand. They can appear any day, they fly all summer. Bronze beetles are red below and golden green above, their females lay their eggs in manure or soil rich in humus, young beetles appear in late summer or autumn, wintering there.

Care must be taken that these rose connoisseurs do not settle in the garden, otherwise they will attack the rose garden with even more next year. Deer behave in exactly the same way, only slightly different in appearance: black beetles, covered with gray hairs and white spots, do not look as impressive as elegant bronzes. It is difficult to scare them away by any means, you need to collect and carry away or destroy, dig up the earth around, do not store manure nearby.

Diseases

Rose diseases are very often caused by fungal spores that are easily spread by wind or insects.

Plants weakened by pests are especially affected by various diseases, so those roses that have already had to be saved from pests should be under special supervision.

It is necessary to carefully examine all parts of the plants, begin to treat as soon as the disease can be recognized.

Mučnistaâ rosa

Young shoots, leaves, buds are covered with a white or light gray powdery coating, deformed and dry out – this means that they were struck by a fungus that causes a disease called “powdery mildew”. All affected parts of the plant must be cut off, if there are not too many of them, then the entire bush (preferably the plants adjacent to it) must be treated with ash infusion. Ash destroys the emerging mycelium, but with a large infection it may not help. The treatment of roses with special preparations will be much more effective: Bactofit, Skor, Fitosporin, Topaz.

Powdery mildew develops in warm summers with high humidity, if roses grow in a ventilated place, there is no excess of fertilizers, then they are less susceptible to this disease.

Black spot

If black spots appear on the leaves in mid-July, the lower leaves quickly turn yellow and fall off, then another fungus is to blame, which damages the adult leaves of roses. If the disease is started, then sluggish young leaves may remain on the bush, the rest will simply dry out and fall off.

At the first manifestations of the disease, it is necessary to remove the damaged leaves, treat the entire bush (and surrounding plants, not necessarily only roses) with Bordeaux liquid or special preparations: Fundazol, Profit, Topaz, Ridomil Gold.

Rust

The spores-causative agents of this disease are carried by water, in the spring in April – May, specific growths, spermogony suddenly appear on the leaves, they first have a yellow color, and then turn black closer to autumn. Pustules from the lower part of the leaf plate scatter spores, affecting nearby plants. The affected plant looks terrible – its leaves become covered with black and dark brown spots, they dry out, the shoots are bent, cracked, spores fly out of the cracks, infecting everything around even more. This disease affects berry bushes, and not just roses.

For treatment, copper sulfate, Bordeaux liquid, Topaz, Bayleton, Abiga-Peak are used. For prevention, at the beginning of autumn, the bushes are sprayed with Bordeaux mixture or blue vitriol, and sanitary pruning is mandatory. Some experts advise treating plants with immunomodulators “Zircon” or “Elina-extra” for prevention.

Chlorosis

Chlorosis cannot be called a disease in the full sense of the word, it’s just that the roses lack iron, and they look unhealthy – the leaves turn pale, become covered with yellowish spots, or the entire leaf becomes much paler (yellow) than the veins that remain green. Iron is a very important element for the overall health of the plant and for the balance of all other elements in its body. As a rule, iron is contained enough in the soil, but it is not absorbed by roses for various reasons. For example, the soil may be too acidic or too alkaline, too dense with high moisture and insufficient drainage. Chlorosis usually begins to appear at the tips of young shoots, first it becomes noticeable on young leaves, then gradually gets to the oldest ones.

For treatment, it is not enough (or even necessary) to add iron to the soil, you need to determine the cause and eliminate it, then the balance of useful elements will be restored. First of all, you need to know the level of soil acidity. If the soil is too dense, peat or compost, or even sand, should be added to it to make it more loose and breathable. An excess of phosphorus can also block the absorption of iron, so you should be more careful with complex mineral fertilizers.

Downy Mildew

If dark red or purple spots appear on the leaves, the leaves curl, dry out, the shoots are deformed, cracks appear on them, then the plant is affected by a fungal disease with peronosporosis or downy mildew. The thinnest white cobweb appears on the underside of the leaf, which can be seen with a magnifying glass. Probably, at the beginning of summer, the rose was affected by spores of the pathogen fungus. Rain and wind spread spores, and favorable conditions, that is, a sharp drop in temperature, waterlogging of the soil, lack of ventilation, excessive shading, trigger the disease.

Diseased plants must be completely destroyed, usually they are carried away and burned. If the lesions are small, then you can treat them with Ridomil Gold or Strobi. For prevention, during the formation of buds, plants are sprayed with Bordeaux liquid or Kuprozan.

Preparation of spray solutions

Flower growers often treat rose diseases by spraying bushes with special solutions. Often used a copper-soap solution or lime-chlorine decoction, in the preparation of which there are nuances.

To prepare a copper-soap solution, use soft hot (at least +50 degrees) water, if there is no rain, then tap water can be softened by adding soda ash (5 g per 10 l of water) or mustard (2 g ). It is best to take green soap, 300 g is dissolved in 9 liters of water, but if it is not available, you can use 72 percent household soap.

Copper sulfate (30 g) is separately dissolved in 1 liter of hot water, and then it is poured into the soap solution in a thin stream, constantly stirring with a wooden stick. A properly prepared solution has a pleasant blue color, it should be liquid without sediment and flakes. Before use, it is cooled to +20 – +25 degrees, it is not necessary to spray hot bushes. You can store the finished solution for no more than 5 hours.

For lime-chlorine decoction, you will need 2 liters of ground sulfur and 1 liter of quicklime (or 1,5 liters of slaked lime) and 17 liters of water. Lime must be quenched in water so that there is no violent boiling, take a little water. When the water is heated, sulfur and the rest of the water are added, everything is constantly stirred. The mixture must be boiled over very low heat for at least 50 minutes, a properly prepared liquid will acquire a cherry color. During boiling, the volume of water must be replenished, for this it is added no later than 15 minutes before the end of the preparation of the preparation. Then the broth is defended, after cooling it is filtered into a glass or earthenware dish, but not metal. If there is a hydrometer, you can check the strength of the prepared broth. Its normal density usually falls within the range of 1,152 – 1,162 g – per cubic centimeter. This is a concentrate, it is diluted for use. For 10 liters of water, you need to take from 180 to 220 g, a couple of days before the treatment, it is necessary to carry out a test spraying of one bush (or even part of it). If there is a burn on the plants, then lime should be added to the broth. Store the finished product in a dark, cool place, the dishes should be tightly closed.

If you carefully consider the preparation of preparations, they will certainly help roses get rid of pests and not succumb to diseases.

Video “Diseases of rose bushes and their treatment”

From the video you will learn about the most common diseases of roses and how to treat them.