Content
Stem gall midge on raspberries is a dangerous pest that can lead not only to the loss of 80% of the crop, but also to the death of the raspberry tree. In appearance, an adult insect resembles a bright orange mosquito. To combat it, folk remedies, as well as chemicals, are used. If the infestation is severe, three treatments will be needed per season.
What is a gall midge
The gall midge (Cecidomyidae) is an insect from the order Diptera. It is a dangerous pest that attacks raspberries and many berry crops, as well as fruits, grains, legumes and ornamental plants. In total, there are almost three thousand species in the gall midge family, with two of the most common:
- Runaway.
- Stem.
They can be found in all regions of the world, including in different regions of Russia.
Appearance
Adult gall midges resemble small mosquitoes. The body is no more than 2 mm in length, the abdomen is orange-red, the wings are transparent. The larvae are the same color, but they are larger - they reach 3-4 mm in length. They overwinter in the surface layer of soil (depth up to 3 cm) under raspberry bushes, as well as at the base of shoots.
In May they turn into pupae, then young insects emerge from them (adult stage). They mate, the females lay eggs in cracks, damage to the raspberry bark, and at the bases of leaf petioles (mainly in young shoots). Then orange gall midge larvae emerge from the eggs again. They unite in colonies (up to 200 individuals each).
An adult insect can be easily identified by its bright color
What harm does
Damage to raspberries and other crops is caused by two generations of shoot gall midge larvae. The first appears in June and poses the greatest danger. The second generation spreads in July. The larvae do not gnaw through raspberry tissue because they have a small head and no piercing parts. Instead, pests secrete special substances that lead to rapid cell division and the formation of a dense round formation - a gall. This is what gall midges feed on.
It is quite simple to determine the invasion of stem gall midges on raspberries - the insect’s body is orange, as shown in the photo. There are also other signs of its appearance:
- formation of ridges on the surface of the bark;
- the appearance of swellings, thickenings;
- withering and drying of stems.
Gall midge is a dangerous pest of raspberries. The appearance of an insect leads to negative consequences:
- 10-15% of affected shoots die in winter due to frost.
- In the second year, the affected raspberry shoots produce leaves with a significant delay.
- More than half (up to 70% of the buds) may not bloom.
- The stems break, especially under the weight of snow and gusts of wind.
If measures are not taken, from 30% to 80% of all raspberry shoots may suffer, especially young growth. This naturally leads to a reduction in yield by 5-6 times.Sometimes it is not possible to collect even 1 kg of berries from a raspberry bush during the entire season.
Raspberry disease can be visually identified by the formation of purple spots on the surface of the bark. In this case, it is necessary to treat not only insecticides, but also powerful fungicides.
Causes of infection
Since the gall midge is widespread, it is not possible to completely avoid damage to raspberries. There are several factors that provoke an insect invasion:
- cracks and other damage, especially on young shoots;
- excessive amounts of fertilizer, which can also lead to cracking of the bark;
- too frosty November and December combined with an early warm spring;
- planting raspberries in lowlands where there is stagnation of water, as well as flow of cold air masses.
A shoot affected by a pest can be identified visually
Measures to combat crimson gall midge
Various methods are used to combat stem raspberry gall midge. Chemical preparations are the most effective. But if the raspberries are already bearing fruit and the harvest is ripe, it is better to use folk remedies. Also, do not forget about preventive treatments of shrubs, which are carried out in mid-spring.
Chemical preparations for raspberry gall midge
Chemical insecticides help fight not only raspberry gall midge, but also other pests. As a rule, it is enough to carry out only two treatments to achieve the desired result. Among the effective preparations for raspberries are the following:
- "Karate".
- "Fufanon."
- "Spark".
- "Karbofos".
- "BI-58".
The products are used strictly according to the instructions, since many drugs are toxic to humans, animals and beneficial insects. The solution must be prepared in quantities that can actually be used in one treatment - it cannot be poured into the general sewer system.
Folk remedies
Folk remedies show their effectiveness in the early stages of the invasion. It is possible to treat raspberries on which stem gall midge has appeared at the fruiting stage, when there are several days left before harvesting. Mostly summer residents use the following recipes:
- Treatment with dandelion infusion. After weeding, the grass is sorted (along with the roots) and chopped with a shovel. Take 2 kg of raw materials and pour 10 liters of water at room temperature. Leave for 2 to 12 hours, then filter and bring to a total volume of 10 liters. Treatment of raspberries against gall midges should be done every 2-3 days until the pest is completely destroyed.
- You can also get rid of gall midges on raspberries using a water emulsion of kerosene - 100 ml per 10 liters. Treatment is carried out at the end of May and again in mid-June. For raspberries, 2-3 sprays are enough.
- Chop the cloves and fresh garlic, take 500 g of raw material and add a bucket of water at room temperature. Leave for a day, filter and process the raspberries several times at intervals of 2-3 days.
- You can also take onions along with the peel, chop 1 kg of raw materials and pour 10 liters of warm water (but it should not be hot). Leave for 3 hours and add half a piece of grated laundry soap. After this, mix thoroughly, strain and begin processing the raspberry bushes.
Spring spraying should be carried out after sanitary pruning.
In this case, the treatment must be done no later than the end of April, since the larvae become active already in May.
Prevention
It is quite possible to prevent the appearance and active reproduction of gall midges on raspberries. There are several proven ways to do this:
- When planting, choose well-lit places. They should not be located in lowlands.
- Trim all damaged branches in a timely manner. It is on shoots with cracked bark that gall midges often settle. They are pruned in early spring, before active sap flow begins.
- Do not give too much fertilizer - it is better to underfeed a little than to overfeed. If the soil is fertile, it is enough to fertilize twice – in early spring and at the stage of bud formation.
- In April, it is recommended to carry out preventive treatment of raspberries with insecticides. Damaged shoots should be sprayed especially carefully. At this point, you can even use chemicals, since about two more months will pass before fruiting begins.
- If there was previously a gall midge infestation, in the spring the top layer of soil up to 3 cm deep is removed.
- Periodically, you should loosen the soil and do weeding at the same time.
- In the fall, it is necessary to lay mulch from chopped tomato or potato tops. Raspberry leaves, on the contrary, should be taken as far away as possible.
- In the fall, inspect the bushes again and remove damaged raspberry shoots with cracked bark.
When planning new plantings, it is recommended to choose those raspberry varieties that have satisfactory or high resistance to gall midge. These include: Pride of Russia, Zorenka Altai, Ruby Seedling, Vera, Bell, Arched.
Raspberry Vera is one of the varieties that is highly resistant to gall midge
You should also pay attention to varieties that are less susceptible to bark cracking than others: Torch, Vera, Credo, Sokolenok, Rubinovaya, Blestyashchaya, For Health, Troyana.
The most severely affected by the gall midge are the following raspberry varieties: Barnaulskaya, Zorenka, Ogonyok, Daughter Vislukha.
Conclusion
Stem gall midge on raspberries is quite dangerous. The insect multiplies quickly and can infect not only raspberries, but also bushes of other plants. Therefore, it is necessary to fight at an early stage. If the invasion is severe, and even chemicals do not help, it is easier to destroy the raspberries, disinfect the soil, and then plant new varieties that are resistant to gall midge.
