One of the most common pests of currants is glass beetle. This insect causes significant damage to the bush.
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The problem is that it is very difficult to notice an infestation by this pest. And this makes the fight much more difficult.
In today's article we will tell you what glass is, why exactly it is harmful and how to deal with it.
What does the pest look like, signs of appearance on plants
First, let's figure out what the pest itself looks like.
The adult insect resembles a wasp with its black and yellow coloration. It has a more monolithic body. The wasp has a pronounced waist, while the glass beetle does not.
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The wings of the insect have a clearly noticeable orange-brown tint. In addition, the glass is rather black with yellow stripes. He also has a long black mustache.
The caterpillar is small (about 2 cm), yellowish-gray in color and has a red-brown head. It is very difficult to detect, since it lives in the core of the currant branch.
ON A NOTE. After itself, the caterpillar leaves a channel along the entire length of the shoot.
It is very, very difficult to determine invasion in the early stages. The fact is that outwardly a diseased bush is no different from healthy ones.
Only over time do the infected branches begin to show signs of the presence of glassworm. Namely: withering of foliage, drying of branches, stunting of growth, decreased yield.
Description of the pest
In appearance, the imago (sexually mature individual) looks like an elongated wasp with a long, black, fluffy body and bright yellow stripes on the sides. A distinctive feature is the structure of the wings; they are narrow, long, and form a triangle when open. When the insect folds them, the transparent wings lie in the middle of the back as a thin bar with widening at the ends.
The entire body of the insect is covered with numerous hairs, making it appear velvety. There are hairs on the legs and wings. The long antennae are fancifully bent upward, forming a small semicircle.
Important! The female has three yellow stripes, the male glass has four.
Adults feed on plant sap or pollen on flowers. In the 20th of May or early June, the female lays up to 50 eggs. They are long up to 7 mm, oblong in shape. The eggs are placed in the bark of the currant shoot very close to the young bud. After 1-2 weeks the larva appears.
What harm does it cause and what plants does it affect?
In addition to currant bushes, the pest is also not averse to eating gooseberries and raspberries.
Infection usually begins in May-June. The adult lays eggs on the shoots of bushes, trying to place them in small cracks on the branches.
After about a couple of weeks, caterpillars emerge from the eggs. They bite into branches and get inside. There they feed on the tissues and sap of the plant.
During growth, the caterpillars move down to the base of the branches. This leads to drying and death of the shoot.
If you have strong currant bushes, they will be able to survive the pest’s impact. But the yield of berries will be significantly reduced.
It is noted that glass can reduce the harvest by half.
It causes the greatest harm to summer residents in Central Russia.
Why is currant glassware dangerous?
Glassworm most often affects black and red currants, however, the insect also harms other crops. In particular, raspberries and gooseberries, whose inflorescences insects feed on, suffer especially badly from the pest.
Glasswort is dangerous because its larvae quickly go inside the shoots, where they are difficult to reach with the help of insecticides and biological preparations. In order to effectively influence them, it is important to treat the bushes at a time when the caterpillars are still visible. It is very difficult to catch this period.
Below is a photo of a fully developed glass beetle on a currant.
An adult insect vaguely resembles a wasp
Life cycle and reproduction of the pest
The glasswort lays eggs on currants in June, however, if the year is warm, this can happen as early as May. They are located next to the buds on young shoots or in depressions on the bark. After 1-2 weeks, the eggs hatch into larvae that quickly gnaw their way into the branches. Having settled under the bark, they gradually move down, feeding on the core of the bush. As the caterpillars develop, the currant shoots begin to turn black and become brittle.
They remain under the bark of the currant bush for two years, and after the second winter they pupate. The larvae then become butterflies, which lay eggs again and the cycle continues.
What harm does glass do to currant bushes?
This pest can greatly reduce the yield of berries due to the fact that its caterpillars eat away the core of the shoots. One larva is capable of eating about half a meter of the total length of the branch, as a result of which it turns black and stops bearing fruit, and then breaks off completely.
Red currant varieties suffer the most from glass, however, it is also found in large quantities on bushes with black berries.
Signs and causes of damage
Adults look like small wasps with a more elongated body. The insect's wings are narrow and long with a span of about 25 mm. Despite its resemblance to a wasp, the glass beetle is a harmful butterfly. Its wings are transparent, however, there is an orange border along the edges. The veins are black.
The following signs indicate that this pest has infected currant bushes:
- plants drop unripe berries;
- the number of peduncles is very small, despite good care;
- fruits set poorly;
- if you make an incision on the shoot, you will find a black core inside;
- the leaves of the bush become noticeably smaller;
- the growth of branches is greatly reduced - the bushes add only about 10 cm in height per season;
- currant shoots wither and dry out;
- in hot weather, plant foliage quickly turns yellow and falls off;
- ripe berries are too sour.
Advice!
Wilted branches that are affected by glassworm must be cut down to the very base and burned to facilitate further control of the insect. The photo below shows what kind of trail the currant glassworm caterpillars leave behind.
A black hollow circle is clearly visible on the cut of the shoot
Folk measures to combat glassware on currants
First of all, let's discuss traditional methods of fighting insects.
Pruning and destroying diseased shoots
This is a simple but effective method. Prune dead branches to prevent the spread of larvae.
Jam traps
This is not exactly a control method, but a way to detect pests and determine when to begin combating them.
Place baits with fermented currant jam along the perimeter of the currant plantings. If you find glass particles in them, start processing.
Garlic infusion
Press 1-2 heads of garlic and fill the mixture with water. Let it brew. Then strain and treat the plants after flowering.
Sand and kerosene
Pour sand into a basin and soak it with kerosene. Make several of these preparations and place them between the currant bushes. The smell of kerosene will scare away the glass from the bush.
Aromatic infusion
Glasswort cannot stand the smell of pine needles, rotten onion skins, wormwood, shag and tansy. Make an infusion based on one of these products and treat the bushes before flowering and immediately after it.
Ammonia solution
Ammonia, which is contained in ammonia, perfectly repels glassware from your currants. Carry out processing starting in spring. Not only will you drive away the pest, but you will also fertilize the plant with nitrogen.
Signs of damage to a currant bush
Shoot damage can be difficult to diagnose until significant damage has been done to the plant. But if you look closely, you will notice that the leaves and fruits on the infected branches are smaller than on the others. By the end of the season, the foliage on these shoots will wither.
Flowers may dry out immediately after flowering, as well as some of the leaves, since this is the time of active feeding for growing caterpillars. If the branch was powerful, then it will not wither completely and next year you will notice dark holes on it. This means that young butterflies have flown out of them.
In order to begin to fight the pest, it is necessary to accurately determine the problem by checking the suspicious escape. It needs to be cut and cut lengthwise. In this case, you may notice inside the passage of the larvae, themselves and their excrement, similar to dust.
Important! The reaction of moths to pheromones is used in the manufacture of pheromone traps, which reduce the likelihood of infection of bushes. Inside the structure there is a sticky layer to which the males that arrive on the scent stick.
Effective drugs for glassware
In addition to folk remedies, you can protect currants with the help of insecticides. In the table below we have collected for you the most effective drugs for glassware.
Table. Effective insecticides for glassware
| A drug | Method of preparation / method of use |
| Fitoverm | 2 ml / bucket of water. Treat at the rate of 1.2 - 1.5 liters per bush |
| Agravertine | For every liter of water add 1 ml of the drug |
| Bitobaxcillin | For every liter of water add 7 ml of the drug. Use same day. Consumption rate for 1 bush – 0.5 l |
| Lepidocide | You need 50 ml of product per bucket of water |
| Iskra M | For every liter of water add 1 ml of the drug |
| Fufanon | For every liter of water add 1 ml of the drug. Treat at the rate of 1.2 - 1.5 liters per bush |
| Nemabact | Processing of planting material |
| Inta-Vir | Process during the growing season. Preparation rate: 1 tablet per bucket of water |
| Anthonem-F | Processing of planting material. Spraying in the “green cone” phase |
ON A NOTE. Treatment with drugs is carried out twice per season. The first time is immediately before flowering, the second time is 1.5 - 2 weeks after flowering.
How to properly treat plants
It is very important to process currants correctly.
You should start spraying with folk remedies or chemical insecticides in early spring. The landmark is the appearance of the first leaves.
The fact is that at this time the caterpillars crawl out to turn into pupae. By processing you will destroy them.
The second treatment should be carried out in May-June before flowering. At this time, adult butterflies fly in to lay eggs on currant shoots.
The third spraying is carried out after flowering. Its goal is to destroy adults and, if possible, larvae that are located inside the bark.
The consumption rate of the working solution per bush is calculated individually depending on the size. On average this is 1-1.5 liters of liquid.
Signs of a pest and damage caused
Since the insect larvae are located inside the stem, in its core, it is difficult to notice them. The presence of a pest can only be determined by external signs on the bush, when the damage has already been done:
- wilting and drying of leaves and shoots above the location of the pest;
- insufficient development of berries;
- change in color of the bark of the shoots, it becomes lighter;
- the presence of pupae on shoots and butterflies on leaves.
If you break the damaged shoot, which, by the way, can be done easily, since the tissues lose their strength, then the black core will be clearly visible. This is a characteristic feature by which currant glass is identified.
The leaves of the bushes on which this pest has settled wither and begin to dry out, nutrition is disrupted, including the ovaries, the fruits develop poorly, become smaller, and taste more sour. Eventually, the plant may die.
Frequency of glass glass treatments
You need to work with currants, preventing the appearance of the pest, throughout the season.
In the spring, before the bush wakes up, you need to carry out sanitary pruning.
It is also important to constantly remove fallen leaves, broken twigs and rotten or dried berries.
At the beginning of the growing season, the bushes are sprayed. Often this is not necessary. Chemicals are used no more than 2 times per season: before and after flowering.
It is acceptable to use folk remedies more often, but do not treat currants with them during flowering. After all, this way you will scare away the bees and bumblebees that pollinate the flowers.
Before wintering, pruning must be repeated. Again, diseased and dry branches are cut out.
Bush pruning
It is better to cut out severely affected currant, raspberry or gooseberry plants at the root and burn the branches. If black depressions are visible on the stumps that go down, the larva may have descended almost to ground level. It is advisable to uproot the currants and burn everything.
Slightly affected branches are cut back to healthy wood in the spring, before the buds awaken. If, after the leaves appear and flower, they quickly wither, such shoots must be cut off and burned. The cut areas are treated with garden varnish.
If necessary, pruning is repeated in the fall, after the leaves have dropped.
How to properly prune if the pest has already appeared
The most effective method of dealing with glassware is to destroy infected shoots.
If your berry bushes often fall prey to this pest, then pruning should be done regularly throughout the season.
Weak and dried shoots need to be filed. Moreover, they need to be removed until the wood is clean. That is, until the black channel disappears.
If you have to, cut right to the root. Otherwise, the larvae will remain inside the bush.
IMPORTANT! All sawdust shoots must be burned so that the glass caterpillars cannot escape.
Also, do not forget about preventive pruning of bushes. You can read more about this in our article “Pruning currants in spring, schemes for beginners.”
IMPORTANT! Do not forget to treat the cuts with garden varnish to prevent re-infection or the penetration of a fungal infection.
Natural enemies of glassware
The parasites are the natural enemy of the insect. You can attract them to your site by planting basil, dill, caraway seeds or mint.
They find a glass larva, insert a long oviduct into its body, which is located at the end of the abdomen, and lay an egg. As soon as the ichneumon ichneumon larva emerges inside the body of the glass caterpillar, it begins to feed on it, and it dies. This method can significantly reduce the number of pests in the garden, and the rider can find the caterpillar even where chemicals cannot reach.
Prevention of occurrence
It is very difficult to notice the appearance of the pest, since the caterpillars immediately hide inside the branches. Therefore, it is very important to take preventive measures for the appearance of glass:
- Before planting new seedlings, be sure to inspect the planting material. It is better to destroy sick and questionable specimens to prevent infection of the entire garden;
- Carry out preventive pruning of currants. If you find infected shoots, prune them back to clean wood. Burn diseased branches;
- Inspect the bushes regularly throughout the season. Remove dried branches;
- Plant nearby plants whose aroma repels glassworms. Among them are onions, garlic, marigolds, elderberries, tomatoes;
- Do not plant currants, raspberries and gooseberries near bird cherry trees. Bird cherry attracts glassworts with its aroma;
- Carry out preventive treatments with aromatic infusions and decoctions;
- Starting in June, periodically treat shrubs with bioinsecticides. By destroying the butterflies, you will prevent the appearance of caterpillars.
Common mistakes
Let's look at the mistakes that summer residents make when fighting glass.
- Complete removal of the bush when an infected branch is detected. There is no need to destroy the entire currant bush. Cut only infected branches.
- Preventative pruning is not carried out. Because of this, the larvae quietly develop inside the currant.
- Treatment with insecticides during flowering can lead to the death of bees and lack of pollination. As a result, you may be left without a harvest at all.
Answers to frequently asked questions
How to detect glass?
Unfortunately, in the first year this can only be done by chance. At first, diseased bushes are no different from healthy ones. The pest will begin to manifest itself only 2-3 years after the invasion.
What effective control methods exist?
The pest can only be dealt with comprehensively. This includes pruning diseased shoots, treating with drugs, and planting repellent plants.
Currant varieties resistant to glassworm damage
Today there are no currant varieties that are completely immune to this pest. However, relatively resistant species include the following:
- Summer resident;
- Natalie;
- Perun;
- Early sweet;
- Vigorous;
- Sechenskaya-2.
These varieties are attacked least frequently by glass, but can still be found on them.
