Very ugly growths, swollen areas on the leaves of red currant varieties are the results of the activity of gall aphids. The pest feeds on the juices of the crop and causes deformation of its green parts. Aphids love fresh shoots most of all - by destroying them, they reduce the chances of high yields in the future. The gall aphid is visually similar to other species of aphids.
The length of the insect is usually no more than 2 mm; there are insects without wings, which in some generations (they will be discussed in the article) become winged. Among the differences are a pale green-yellow (even transparent) cover and a hairy body.
Over the course of one season, up to two dozen generations of this insect develop - and the warmer the climate in your region, the higher this figure. High fertility only further aggravates the harmfulness of the aphid - you think you have defeated it, but it turns out that another offspring is on the way.
Pest life cycles
Aphids suck out the main juices from currants, thereby depleting the shoots and causing a decrease in yield. To heal the resulting wounds, the plant produces additional tissues that form gall growths. If nothing is done about the aphids, they will reproduce new offspring and eat the branches until they are destroyed. Find out why swollen buds appear on currants in this article.
Aphids attract ants to the garden, which protect the harmful insect from entomophages and contribute to its maximum active reproduction. The ants themselves are also of no use to the garden; they love to feed on grape and strawberry juices.
Gall aphids are the main cause of viral infectious diseases of currants.
Young shoots, even after the pest is exterminated, grow poorly, take a long time to recover and may not fully recover at all. The natural result of this is a deterioration in yield. The life cycle of an insect is characterized by the phenomenon of polymorphism. The point is that different generations of insects differ in appearance and can perform certain functions. Let's take a closer look at this point:
- The founder emerges from the egg. She plays the role of the foremother of all seasonal generations of individuals. The founder is a parthenogenetic viviparous species - it produces viable insects only of the female sex, which are responsible for the generation of new offspring.
- Virgins are the main part of the gall aphid that can be seen on currants. Virgins do not have wings, so the insects live on the host plant all the time, the females reproduce their own kind.
- The scatterworm is a winged pest. When the colony grows or the food supply is greatly depleted, the dispersers fly to new places and make their next settlement there.
- Polonoski are a transitional generation of insect pest, from which females emerge that are capable of laying eggs.
- Females and males are bisexual generations responsible for wintering. They lay eggs in the stems, from which the foundresses emerge in the spring.
How does the pest develop?
The leaf gall aphid lays eggs under the bark of red currant branches closer to the buds. Here the larva, depending on the specific climatic conditions of the region and weather factors, can stay up to 9 months. In the spring, as the buds open, the foundresses emerge from the eggs and begin to colonize the plant. The insect reproduces during the abundant flowering of the bush. The peak of harmfulness occurs in June, when the colony becomes largest. In the second half of summer, the currant leaves become coarser, and the aphids settle on intermediate plants. Several more generations of the pest, which we wrote about above, feed on the leaves. A bisexual generation is immediately hatched, which will eventually return to the currants to lay eggs (that is, closer to autumn). Read how to protect currants from aphids here.
Leaf gall aphid (Capitophorus ribis)
This small insect most often damages white and red currants. In the spring, when the first leaves bloom, larvae appear, which settle on the underside of the leaves and suck the juices out of them. Gradually, these larvae become the founders of a new colony, damaging more and more leaves. Red swellings appear on their outer surface. Then the leaves begin to die, a drop in yield and the gradual death of the entire plant.
Leaves damaged by aphids
Folk recipes
Some plants contain pyrethrins, fungicides and other substances that have a destructive effect on gall aphids. Use this knowledge to control pests. This material will tell you about ammonia for aphids on currants.
Folk remedies used to process currants are quite effective, but in the early stages. If the pest has severely affected the bushes, chemicals are needed.
To enhance the effect, liquid soap is added to the infusions, enveloping the insect’s body and blocking its access to oxygen. Basic recipes:
- Tincture with tobacco dust - take 300 g of dust, pour boiling water over it and leave for several days. Strain, add laundry soap dissolved in water, liquid dishwashing detergent, and use for spraying.
- Tincture of marigolds – pour half a bucket of crushed dried or fresh flowers with a bucket of hot water, leave for a couple of days. You will need to add 50 g of soap (liquid) to the finished strained solution.
- Infusion with mustard - take 25 g of dry powder for 10 liters of solution. First, it is recommended to make a concentrate - infuse the powder in a liter of boiling water for 48 hours. As in the previous two options, it is advisable to add soap.
Why are aphids dangerous on currants and berries?
Among the aphid species, the gall or redcurrant aphid (Cryptomyzus ribis) is common in all regions where currants are grown. The insect parasitizes most often on red, white, and yellow currants. Black and golden currant varieties are resistant to this insect.
Often in a garden where there is activity of ants carrying aphids, not only currant bushes suffer, but also other plants (mint, sage, oregano, lavender, thyme, etc.). Therefore, it is not worth planting these crops together.
The insect has a small body - up to 2 mm, covered with thin hairs, without wings. The color of the aphid is pale yellow or greenish. Gall aphids reproduce more actively in warm weather and 2-4 generations of insects are born during the season. In this case, the female gives birth to living females for further reproduction.
It is easy to notice the appearance of aphids on currant leaves:
- Leaf blades are deformed;
- Swellings and tubercles appear on the surface of the leaves.
The plant is trying to save the green mass. In places where the punctures are punctured and the juice is sucked out, new expanded tissue, the so-called galls, is formed. This is where the name gall aphid comes from.
Insecticides
If the gall aphid has proliferated greatly, it will not be possible to do without insecticides. Since chemicals are quite aggressive, spraying is done during budding, and then after harvesting. Main drugs:
- Calypso is a universal insecticide that causes the death of parasites within 12 hours after direct contact. Available in the form of an emulsion, bottles have a volume of 10 or 100 ml, there are ready-made infusions with sprayers (not concentrates). Calypso can be used together with other chemical preparations for aphids, growth regulators, except those that have an alkaline reaction and contain copper. Hazard class 2, the use of personal protective equipment is mandatory. The emulsion is diluted at the rate of 1 ml per 2 liters of water; if the damage is severe, the concentration can be doubled. The leaves are sprayed on both sides. Repeated processing is permissible no earlier than after 10 days.
- Cofidor Maxi is a broad-spectrum insecticide that affects the nervous system of pests. You will see the first results in the first hours after spraying - insects become slow and begin to die. You can add Kofidor Maxi to root dressings; rain practically does not wash off the active substances from the leaves. Release form: powder in 1 g sachets. Hazard class 3.
The bag is designed for one-time use - 10 liters of liquid will be enough. The concentration is sometimes increased if the lesion is very severe.
- Actellik is a universal insecticidal preparation that has high activity against aphids, weevils, mites, whiteflies, and other insects. The main active substance is pirimiphos-methyl. Release form: 2 ml ampoules, diluted in water. The action begins a few minutes after spraying, expect maximum results within 3-4 days. The contents of the ampoule are diluted in 2 liters of water and mixed thoroughly. This amount is enough to process 10 squares of plantings.
- Vofatox is an insecticide-acaricide, effective against most insect pests. Dilute the contents of the ampoule in 5-10 liters of water, depending on the extent of the damage, and use for spraying.
- Proteus is a combined action insecticide, oil formula. Works well at ambient temperatures from 8 to 30 degrees. Not toxic to plants, there is a possibility of developing resistance, the effect is noticeable within 3-4 days. For treatment, use solutions in serial sprayers (they are ready for use).
The drug should be prepared for one use.
What harm can it cause to currants?
Typically, gall aphids like to eat red currants - they have thin leaves that are easier to pierce and suck out the juice. A lump forms at the site of the bite. Those who are not familiar with aphids may think that the currants are infected with something. If you turn the leaves over, you can see the insects that have settled there.
Gall aphids can harm currants in the following ways:
- deform leaves;
- attract other insects - ants and pest beetles;
- deplete shoots;
- reduce the harvest to a minimum;
- infect shrubs with various types of viral infections;
- atrophy old and new shoots;
- stop the growth of fresh growths on bushes;
- in the end - destroy all the bushes that cannot be restored or subsequently exploited - the currants will simply dry out.
Biological
Biological preparations are also effective, but not as toxic as chemical insecticides. Let's look at the most popular:
- Bitoxibacillin - the formula contains protein crystals and bacteria. It is sold in the form of a concentrated solution - it is diluted at the rate of 100 ml per bucket of water. Use sprayers for processing. In hot weather, the procedure is carried out with a weak solution, but more often. Bitoxibacillin is not harmful to plants, animals, humans, and bees. It is also used several days before the currant harvest.
- Actofit is a biological remedy for aphids, the main active component of which is a natural neurotoxin. Affects the nervous system of insects. The processing efficiency is high, but it depends on the weather and ambient temperature. It is advisable to spray the solution in dry and clear, not very hot weather. In heat of about 30 degrees, the concentration of the solution is reduced by a quarter. Aphids begin to die 3 days after treatment. Actofit does not cause habituation in insects.
Dilute in water immediately before use. Personal protective equipment must be used.
- Avertin is a biological pesticide that blocks the transmission of nerve impulses in arthropods. No resistance was detected. The effect is cumulative, systemic, fumigation. Adsorption by soil particles is fast. The drug is practically not dangerous for humans and warm-blooded animals.
The main active components of biological preparations are spores of bacteria, fungi, and viruses. They enter the intestines of aphids and paralyze its work.
scalding
It is recommended not to scald currants with boiling water immediately. Before using this method, you must perform certain steps:
- Trim the bushes. Use a sharp knife or pruning shears to remove damaged, dried, lagging shoots. Healthy branches should be cut to a third of their length. Next, carry out disinfection by treating the cut areas with a solution of hydrogen peroxide or potassium permanganate (potassium permanganate).
- Protect the rhizome: it is good to cover the area around the trunk with plywood or boards, as boiling water can get on the root system and burn it.
- Tie the branches of the bush with a strong rope - you should get a “sheaf”. To give this shape, select a strong central shoot and bend the rest to it. Thus, the plant is compact and easy to process.
Now the currants are ready to be processed with boiling water, and the positive effect of the procedure will be achieved in full. When the bushes are prepared, you can begin the scalding procedure.
Prevention
Carefully and regularly inspect the currant bushes in order to respond to diseases (terry disease, scab) and pests (caterpillars, scale insects) in time and take action.
Deformation of young leaves appears already in the early stages of the growing season, and red spots may form. Preventive treatments against gall aphids give good results. In the spring, before the buds open, or in the fall, before the leaves begin to fall, spray the bushes and the area around the trunk with a solution of nitrafen. The drug can burn the leaves, so do not be late with treatments. The advantage of the formula is that it destroys the eggs of wintering pests, and they do not become active in the new season. For currants, a solution at a concentration of 3% is sufficient (take 30 ml per liter of water) at the rate of 0.5 liters of the finished product per adult currant bush. Read how to get rid of ants on currants here.
Proper proximity will reduce the risk of currant infection to a minimum. Plant bushes with chamomile, marigolds, and calendula.
Remove weeds from the garden in a timely manner, as aphids love to live on them. Prevention should be done before the buds swell; autumn events will be a continuation of spring ones. Find out about the medicinal properties of Indian onions at this link.
Signs of defeat
Some symptoms may indicate an aphid infestation:
- Leaf deformation.
- The presence of red or orange swellings (sometimes brown) - it seems as if the plant is “baked” in the sun.
- Stopping the growth of new shoots.
- Presence of pests under the lower part of the leaves.
Due to inexperience, you can lose crops and bushes. It is important to know what aphids visually look like in order to eliminate them in time.
conclusions
- Gall aphids feed on the sap of currant bushes, weaken them and ultimately cause death. You can also forget about high yields.
- Folk remedies for insect control are non-toxic and safe, but with significant damage they are useless.
- Insecticides are an extreme measure of control; they can be used to treat aphids and ants in early spring and autumn after harvest. If necessary, the concentration of active substances is doubled.
- Biological preparations are also quite effective against aphids, but do not have a toxic effect on people or animals.
- Do not ignore preventive measures - timely treatments with Nitrofen, proper proximity, loosening the soil and removing weeds will reduce the risk of aphids to a minimum.
Preventive actions
Experienced gardeners carefully monitor the bushes, and if the first signs of damage appear, they begin preventive measures.
Nitrafen
Treatment of currants with Nitrafen is carried out in early spring until the buds open. It includes processing the following parts of the plant:
- trunk zone;
- branches, shoots;
- kidney
Nitrafen is a concentrated drug that is dangerous for plants. Its use is permissible only for a certain period of time. For spraying currants, a composition of 3% concentration is used.
Repellers
Plants that have a pungent odor and are not tolerated by pests are planted as pest repellents. These include:
- calendula;
- marigold;
- chamomile.
Aphids do not tolerate the smell of garlic, onions and tobacco leaves.
In spring, feed with nitrogen-containing fertilizers
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