- The bupestres
- The sawflies
- The leafrellers
- The megachiles
- Cetoines, chafer and white grubs
- Red spiders
- The forceps
Like all cultivated plants, the rose bush is subject to attack by insects, which are found in the many flower buds and freshly formed leaves, a food of choice.
Aphids are the most common parasites of the rose bush. Very prolific and particularly voracious, they develop in colonies, cover in clusters the pimples and stems that they sting to suck the sap. Aphids are harmful to the development of the rose bush, not only because they suck the sap, which no longer benefits the flowers and leaves, but also because they cause the formation of scabies and the proliferation of certain fungi that develop on their droppings. Aphids are also often carriers of viruses. The best known, because the most widespread, the large green aphid, spreads at an astonishing speed from spring until autumn. The last clutches can even overwinter on bark.
The intensive cultivation of the roses makes the action of the natural predators of the aphid, such as ladybugs and some birds, the tit for example. It is therefore necessary to carry out periodic treatments as soon as they appear. You will find in the trade perfectly adapted products which apply by spraying.
Leafhoppers, often confused with aphids, look like tiny cicadas. It is enough to shake a rose bush to see them fly in large numbers, especially during the summer.
The insect itself does not cause any apparent damage to the plant; but the female deeply cuts the bark of the young twigs, on which she lays her eggs in the autumn.
They winter to hatch in the spring. The larvae then settle under the leaves to suck the sap.
To be effective, the treatment must be done in three stages: short sizefollowed by burning of the twigs; summer insecticide treatmentintended for adult insects; oily spray (albolineum, for example) winter, to destroy the eggs.
The bupestres can not go unnoticed since the adult insect is about a centimeter long and is in the form of a golden-colored beetle. You will rarely have the opportunity to see it, because the adult does not cause any direct damage to the plant. On the other hand, you may see some blisters on the bark. If you scratch them, you will find that the stem is pierced with multiple galleries, especially near the graft; these galleries are the result of the egg-laying, then the development of the larvae. This egg-laying takes place in June-July; the eggs overwinter and the larvae develop in the spring. The development cycle is comparable to that of leafhoppers, it is also necessary to fight adults when they occur and carry out an oily treatment during the winter.
Those are Hymenoptera resembling tiny bees, also known as saw flies, because of their large laying appendage reminiscent of the shape of a handsaw.
Among the many species of sawflies, many of them attack the rose bush (sawfly, leafhopper, leafless sawfly, grafted sawfly, sawfly, sawfly and stemborer).
They have in common to lay eggs on the leaves by notching them with their oviposition.
The gray-green larvae grow by rolling the leaves on their own, devouring the blade. Some species (T. shoots) see their larvae digging galleries in the shoots, others (T. stems) in the stems. Spraying or dusting the larvae with parathion product is very effective.
The caterpillar of these butterflies (called caterpillar) is one of the most formidable among those who attack roses. Of unparalleled voracity, it attacks buds or leaves as well as flowers. At night, during the wet October-November periods, the female climbs along the trunks to lay her eggs. They overwinter to kill only in spring, with the rising of sap.
The caterpillar grows up to summer; it reaches up to three centimeters long. She lets herself slide to the ground at the end of a long silky thread; its metamorphosis is then accomplished in the earth. The control of these caterpillars can be done manually for a small number of caterpillars and for a small rose garden. Otherwise, an insecticide spray should be used. For all those who are reluctant to chemical treatments, note the possibility of stinging the foot of the rose, which prevents females from climbing to go to lay.
Always in the radius of the butterflies, let us announce the twisters. There are many species that have in common to attack the leaves they twist by swallowing them woolly tissue to better devour them. They do not disdain young shoots or flower buds, they die to cut only part. Spraying and insecticide spraying are the rule here.
These solitary bees literally cut the rose leaves, as with scissors, piercing real holes up to one centimeter in diameter. They use it to make the nest for their offspring. Only an insecticide treatment will be effective. Be careful, do not be fooled by bees. Better to admit some damage in your roses, rather than risk poisoning the honey of a neighbor beekeeper!
Cetoines, chafer and white grubs
Cetoines and cockchafers were once horticultural plagues, to the point that they are considered responsible, in the middle of the seventeenth century, the last great famines of our campaigns. These big ones beetleswhen they emerge from the ground in May-June, they are affected by a craving that makes them formidable for trees and shrubs. They devour both the leaves and the flowers, and the roses do not escape. After this "devouring" phase, the females return to the cultivated lands where they each lay dozens of eggs.
The refined and loosened soil of the massifs and flowerbeds constitutes a privileged breeding ground. Hatching quickly, eggs give birth to these famous white wormswhich will grow in the soil for about three years. Very active from spring to summer, the whiteworm voraciously attacks the roots of cultivated plants. While most vegetables are the food of choice, shrubs and roses are also attacked. Only the bark of the roots and the scalp are eaten away. This, however, is enough to completely hinder the flowering of the rose and cause wilting of leaves that fall prematurely.
The means of effective treatment remain very limited. It is illusory to hope to kill adults, given their very ephemeral lifespan. The insecticide treatment, moreover, can only intervene in full bloom, which, remember, is formally prohibited (to ensure the protection of honey insects). The destruction of larvae during loosening or even planting is effective, although adult larvae often sink deep into the soil. The soil must be disinfected and treated with a lindane or parathion insecticide.
Tiny insects, mealybugs have in common to be protected by a carapace (cuticle) of varying consistency, and to secrete a kind of wax that earned them the common name of "Sticky lice". They stick on the stems and suck the sap of the plant thanks to a powerful mouthpiece and a highly developed soft rostrum. The round mealybug of the rosebush enters the species called "shieldbecause of its gray scaly cuticle, which protects a winey red insect. Like aphids, mealybugs are extremely prolific; sometimes they end up completely covering the stems of a rose bush, literally covering them with a greyish crust. They particularly like the old branches of climbing roses. It is quite easy to get rid of mealybugs by a winter treatment with white oil (albolineum), and attacking with a powerful insecticide as soon as they appear. Then brush the stems to rid them of dead scale insects, or better burn them.
Thrips are in the form of little black flies very bright no more than three millimeters in adulthood. Rose thrips attacks freshly blooming flowers with a predilection for light-colored flowers. He nibbles them to feed on them; the larvae themselves live at the expense of the flower. It is covered with multiple dark spots, and the petals are wrinkled. Insecticide treatment just before blooming is usually enough.
For a long time unknown to scientists, because invisible to the eye, the mites swarm in our environment. The vast majority of them remain completely harmless; but some directly attack the crops. This is particularly the case mite, better known as the red spider, which affects the apple tree in particular. The adult subjects lay their eggs on the bark, where they are sometimes so abundant that they reveal themselves to the eye in the form of red streaks.
After hatching, the larvae and adult plants bite the undersides of the leaves, which become gray in color, dry out and fall prematurely. As chlorophyll assimilation is interrupted or hindered, flowering can no longer occur.
We must not hide the difficulty of getting rid of mites. Indeed, they resist many insecticide treatments, and it is sometimes difficult to get real acaricide products.
As a precautionary measure, it may be useful to destroy after picking up all the leaves that are spontaneously detached from a rose bush, on which may be attached mite eggs (a greyish viscous substance protects them). Severe size is welcome.
More known as earwigbecause of the strong pincers that the males wear (the females are deprived of them and carry two parallel rods), the forceps readily attack the flowers. They lay their eggs in the ground during the spring; the larvae are, in a way, mothered in subterranean nests until the summer. Insects are active until October. Nocturnes, they move at night. If insecticides can be effective, it is easier to trap these insects by laying on the ground pieces of tiles or slates, under which they come to hide during the day. It is enough then to destroy them, provided to be fast...
They are insects close to leafhoppers, whose green larvae, of rather soft consistency, emit a frothy slime forming white rims around the stems. The presence of this scum reveals that of the larvae, often difficult to spot. An insecticide treatment makes it possible to overcome it quite easily.
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