Content
Lilacs are used for decorative purposes, landscaping areas, and creating hedges. Like any plant, it is susceptible to diseases and pests. Under their influence, the bush develops slowly and may die. Next, pests, lilac diseases and their control are discussed, which will help gardeners preserve the plant.
Lilac pests and their control
Lilac pests feed on buds, leaves, flowers, and branches. As a result, the development of the bush slows down, fewer inflorescences appear, and leaves and shoots are deformed.
Lilac moth
If the lilac has leaves with brown spots, this is the first sign of the appearance of lilac moth in the area. Its caterpillars feed on the leaves of the bush, which turn brown, curl up into tubes and die. At first glance, the plant appears to have been damaged by fire.
Lilac moth butterflies fly out in mid-May - early June. Over 5-6 days, the female lays several hundred eggs on the underside of the leaf. After 5 - 10 days, caterpillars appear and destroy the leaf blade.The second generation caterpillars appear at the end of September. Their pupae overwinter in the soil at a depth of up to 5 cm.
Spraying lilacs with Inta-Vir, Iskra, Karbofos helps fight the pest. The first treatment is carried out at the beginning of flowering and repeated after 3 weeks. Affected shoots are cut off and burned.
Lilac tick
The lilac mite is a dangerous pest that is invisible to the naked eye. Its dimensions do not exceed 0.2 mm. The mite damages the lilac buds, which swell and dry out on the branches. The pest feeds on the sap of young leaves. It overwinters inside the buds and begins to reproduce in early spring. Several generations appear during the season.
Spraying with Carbolineum emulsion at a concentration of 6% helps get rid of lilac mites. Treatment is carried out in early spring. During the growing season, a 0.1% solution of the drug Thiophos is prepared. Spraying is carried out in June during the period of active reproduction of the pest. For prevention, lilac seedlings are kept in a barrel of water before planting.
Acacia false scale
The acacia false scale insect is a small insect measuring no more than 3 - 6 mm. Its body is oval, dark yellow or brown. Pest larvae feed on lilac juice. As a result of their activity, the size and number of leaves, which fall prematurely, decrease. The shoots become deformed and dry out.
The false scale insect lays eggs during May. The first larvae appear in the second half of June, the subsequent ones in early August. The pest overwinters in the bark, cracks on branches, and at the base of branches.
To get rid of acacia false scale, use the drugs Ditox or Sumition. Such products are effective and are not washed off by rain.In private farms, universal insecticides are used - Fufanon and Iskra.
Weevil
The weevil is a small beetle that feeds on lilac leaves. After this, holes of various sizes remain in the sheet plate. The root shoots and leaves of the lower and middle tier suffer the most from the pest.
During the day, weevils are found in bark cracks or fallen leaves. The period of activity occurs in the evening and night. Pests overwinter in bark or soil.
During the growing season, lilacs are sprayed with Fufanon Expert, Vantex, Inta-Ts-M. The product is diluted with water according to the instructions and sprayed on the bush. The consumption of the working solution is 2 - 5 liters per bush. Digging up the soil in the fall gives good results. The weevil ends up on the surface of the earth and dies when the temperature drops.
Apple comma scale
The apple scale insect is a representative of proboscis insects. The female parasite has a gray-brown elongated scute 3 mm long. Males are reddish-gray and small in size. The eggs of the pests are white, oblong, and overwinter under the shields of dead females. The larvae appear at the end of May and spread throughout the bush.
The larvae adhere tightly to the shoots and form a shield. Under favorable conditions, the scale insect multiplies quickly and covers most of the lilac branches. The shrub weakens, produces few inflorescences and becomes depleted.
The systemic drug Ditox helps fight apple scale. Pests die in the first hours after treatment. The drug is not washed off by rain.For prevention, be sure to thin out the crown, cut out root shoots, dry and damaged shoots.
Rose leafhopper
The rose leafhopper is a narrow insect up to 3.5 mm long with green-yellow wings. The eggs of the pest overwinter in the bark at the tops of young shoots. The larvae appear when the leaves bloom in late April - early May. The pest feeds on the sap of leaves. As a result, numerous white spots remain on the leaf plate.
To combat the pest, insecticides Ditox or Alfashance are chosen. The drugs are used in small doses. Their effect appears within a few hours after treatment. The solutions are not washed away by precipitation and remain effective when weather conditions worsen.
The most common lilac diseases and their treatment
Timely diagnosis of diseases will help save the bush. The following are the most common lilac diseases and their treatment with photos. Diseases are divided into several groups, depending on the nature of the lesion.
Fungal
Fungal diseases develop due to the activity of microscopic fungi. The lesion usually spreads in cold and wet weather. The cause of the disease is often weakened immunity of the bush, caused by excess nitrogen and lack of potassium. As a result, the plant becomes susceptible to fungus.
Types of fungal diseases of lilac:
- Powdery mildew. It looks like a white coating on the leaves of the bush. First, small white spots appear, which grow and occupy the entire surface of the leaf. Within a week, the plaque becomes dark and the bush stops developing.The disease affects both adult lilacs and young plants. Most often, its symptoms appear at the end of a cold and damp summer;
- Brown spot of lilac. Appears as gray spots with brown edges. Gradually, the lesion grows, the inner part dries out and falls out. Holes remain on the leaves;
- Anthracnose. The disease is identified by brown spots on lilac leaves. The sores may be orange or pinkish in color with a purple border. The lesion covers leaves, stems, flowers;
- Septoria. The disease appears in the form of light spots: yellowish or gray. Gradually, the damage spreads and causes leaves to wither, shoot tips to dry out, and flowers to fall off;
- Lichens. White spots on the trunk of a lilac may be lichen. These are representatives of the class Mushrooms, which often appear on old trees and shrubs. Plants with cracks in the bark and a thickened crown are at risk. Lilacs affected by lichen develop slowly and are susceptible to other diseases.
To combat lilac diseases, products containing copper are used. This includes Bordeaux mixture, copper sulfate, drugs Topaz, Nitrofen, Oxychom, Ridomil, Skor. They are diluted with water and sprayed on the bush. After 7 - 10 days the treatment is repeated.
To get rid of lichen on lilacs, choose a mechanical method. Take nylon brushes or wooden scrapers and carefully clean the trunk of the bush. At the same time, try not to damage the lilac bark. Then the treated areas are sprayed with a solution of ferrous sulfate at a concentration of 5%. Whitewashing shrub trunks helps reduce the risk of lichen infection.
Viral
The causative agents of this group of diseases are pathogenic viruses.The first symptoms appear in the spring, when the lilac leaves bloom. Dark spots appear on them, mosaic and twisting are observed.
Description of viral diseases of lilac:
- Ring mottling. The disease is identified by light spots and streaks on lilac leaves. Gradually, the lesion completely covers the leaf blade. The virus is spread by pests: nematodes and whiteflies;
- Ring spot. Appears in the form of rounded chlorotic spots on lilac leaves. Symptoms of the disease occur in the first half of summer and early autumn. After a year, the shoots dry out and die. The disease is transmitted by nematodes - microscopic worms that live in the soil. The virus is also spread through gardening equipment.
- Chlorotic leaf spot. This is a disease of lilac leaves on which light patterns appear. Gradually the foliage becomes deformed and falls off.
Viral diseases cannot be treated. If the degree of damage is weak, then the affected leaves and shoots are torn off. The bush is fed with potassium and phosphorus fertilizers. If the disease does not recede, you will have to uproot the lilac and disinfect the soil.
Mycoplasma
Mycoplasma diseases occur when specific microorganisms spread. They occupy an intermediate position between bacteria and viruses. Insects serve as carriers. Mycoplasmas penetrate plant tissues and disrupt their development.
The most common mycoplasma disease of lilac is panicle. On the affected lilac, many thin side shoots are formed, collected in a large bunch.This disease is also called “witch’s broom”. The whole tree suffers from it: the leaves become small and wrinkled, their color fades, and fewer flowers appear.
To prevent the spread of paniculation, preventive measures are taken. High-quality lilac seedlings are selected for planting. During the growing season, the bush is sprayed to control pests that carry the disease.
Bacterial
Bacteria are single-celled microorganisms that feed on plant juices and tissues. Bacterial pathogens develop when there is damage in the lilac bark. Therefore, to prevent them, special attention is paid to inspecting the bush, disinfecting tools, and processing after pruning shoots.
Bacterial diseases of lilac:
- Bacterial shoot rot. If lilac leaves turn black, this is the first sign of bacterial rot spreading. The lesion is also detected on young shoots, flowers and buds. As a result, young and old branches dry out. Infection spreads in places of mechanical damage, and then actively spreads at high humidity;
- Necrosis. The disease destroys the lilac bark, leading to the death of shoots and death of the bush. Infection is facilitated by severe frosts, drought, and the spread of pests. As a result, the lilac receives less nutrition and dies.
If the first signs of bacterial rot are detected, then the lilac can still be saved. The bush is sprayed with a solution of copper oxychloride at a concentration of 5%. The affected areas are cut off and burned. The treatment is repeated after 10 days.
To combat necrosis, the affected areas of the cortex are carefully removed. Then the bush is treated with fungicides.For prevention, it is important to remove fallen leaves and perform sanitary pruning. All cracks and wounds on lilacs are treated with copper sulfate. Then they are covered with a mixture of clay and mullein.
Control and prevention measures
Diseases and pests of lilac depress the bush: they are also dangerous for other plants. Combating them involves the use of various methods. The most popular of them are chemicals and folk remedies.
Chemicals are diluted with water in the required concentration. Be sure to use personal protective equipment. Treatments are carried out in dry, cloudy weather. The frequency of spraying is no more than once every 7-10 days.
Folk remedies are safe for plants and humans. Such methods have no restrictions in use and are well suited for prevention. These include infusions of wormwood, onion and garlic peels, tobacco dust, and wood ash. Lilacs are dusted or sprayed with a solution.
Special measures are taken to prevent diseases and pests. To do this you need:
- use high-quality planting material, without defects and signs of damage;
- perform sanitary pruning of shoots;
- do not injure the cortex, monitor its condition;
- remove fallen leaves in autumn;
- regularly feed lilacs with mineral complexes;
- observe the dosage of nitrogen fertilizers;
- dig up the soil in the fall;
- periodically spray the bush with solutions of insecticides and other preparations.
Conclusion
The lilac diseases and the fight against them given above will help you diagnose the lesion in time and take action. To prevent the bush from suffering from pests, regular spraying with insecticides is performed.To avoid the spread of diseases and insects, agricultural practices are followed and preventive treatments are carried out.
There are light spots on the lilac trunk, practically no leaves, and few flower clusters. With what it can be connected? Photo is avaiable.
Hello. Write to us in the “Ask a Farmer a Question” section. There is an option to attach a photo.
Hello, please advise what to do with the lilac, there are brown spots on it, and nearby peonies also turn black and wither
How to treat a lilac whose leaves are curled up and no pests are visible??
Hello! Have the leaves changed color and how exactly do they curl? Maybe there is an opportunity to send a photo. You can attach it in the Ask a Farmer a Question section.
Why do the leaves on dwarf lilacs curl? I carefully trimmed them before flowering and burned them. No pests were found. What can be done to treat it? Thanks for the help.
Good afternoon
There may be several reasons for leaves curling in dwarf lilacs. And in this case, it is important to pay attention to the accompanying signs.
• There is a viral disease called leaf curl. Most often it affects ornamental shrubs. The cause of the disease is a virus transmitted by ticks. A concomitant symptom of the virus is yellowness and fragility of lilac leaf blades. In this case, curling occurs mainly along the edges of the leaves. It is necessary to cut off and burn the affected leaves. If the disease spreads, you will have to remove and burn the entire bush so that the disease does not spread to other trees and shrubs growing on your site.
• Mosaic. A concomitant symptom of this disease is the appearance of small yellow spots. As the disease spreads and the bush is affected in a more severe form, the leaves begin to curl. You need to act in the same way as in the previous case.
• Pests. Aphids, moths, scale insects - many insects are often the cause of curled leaves on lilacs. It is necessary to regularly remove caterpillars and pupae, and treat the bush with insecticides. Such drugs as Fitoverm, Fufanon have proven themselves well. If aphids appear on your lilac, you need to fight not only aphids, but also ants. They are the carriers of aphids.
• Lack of nutrition. This is the most common cause of curled leaves on dwarf lilacs. In this case, you need to feed the bush with mullein infusion or complex fertilizers.