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Grapes, like many other garden plants, often fall prey to pests. One of the most dangerous insects for this crop is the bunch leafworm, which destroys not only buds and flowers, but also formed clusters.
A small butterfly can do great harm
What does a leaflet look like on grapes
The grape leaflet, as seen in the photo, is a small nondescript butterfly, the length of which is about 8 mm, and the wingspan is about 15 mm. In the free state, they are folded along the body in the shape of a bell.
The anterior trapezoidal wings of the insect are olive-brown or brown-brown in color with a wide yellow-white border, speckled with light gray dashes. On each of them, closer to the inner corner, ocher-yellow spots are clearly visible, spreading towards the front edge.
The triangular hindwings are grey, lighter at the inner corners and darker at the edges.
The eggs of the grape leafworm are so small (0,5-0,6 mm) that they are almost impossible to see with the naked eye. Immediately after laying, they look like translucent balls with a greenish tint, and by the time they ripen, they become yellowish-cream in color.
The larva of this pest is small, about 10 mm long, caterpillar with a brown head and a yellow or grey-green body.
The length of the pupa of the bunch leafworm does not exceed 6 mm. The color of the cover is yellow-brown with a green tint, the tip of the abdomen is yellow.
During the season, three generations of pests change. Butterflies of the first generation lay their eggs on the buds or flowers of grapes, the second on green, and the third on ripe berries.
Leaf roller caterpillars can be arranged in groups
What harm does
The bunch leafworm is a dangerous pest of grapes, which is compared with phylloxera in terms of the degree of damage. The insidiousness of the insect is that the butterfly is active throughout the season, hitting large planting areas.
And yet, it is not the butterfly itself that poses a danger to the grapes, but its caterpillar, which immediately after birth begins to devour the buds, forming wide and deep pits in them. Moreover, insects destroy not only part of the shell, but also the stamens with the pestle.
After eating the first bud, the grape leafworm, with the help of a web, attracts the next one, then another and another, braiding the damaged parts of the plants with a dense cobweb.
Unlike their predecessors, which feed on buds and flowers, the caterpillars of the third generation grapevine leafworm eat the berries from the inside, causing them to become dry and wrinkled.
Thus, one leaflet during the period of its activity can damage 40-60 buds or fruits. In addition, the active activity of the pest leads to damage to generative buds.
If you do not fight with the bunch leafworm on grapes, it is capable of destroying more than half, and with a particularly large number, the entire crop.
Leaf rollers and leaves suffer from a pest
Damage symptoms
The first sign of the presence of a grape leaflet on grapes is a dense cobweb entangling leaves, flowers and berries. Corroded leaves, buds and flowers, dry and rotten berries also speak of the harmful activity of a gnawing insect.
Traces of leaflet activity are visible to the naked eye
Traces of leaflet activity are visible to the naked eye
Causes of appearance
The main reason for the appearance of the grape leaflet on grapes is warm weather, in which the summer of butterflies is activated.
The spread of pests is also facilitated by a large density of plantings, an abundance of weeds in the root zone and ignoring the preventive treatment of grapes from grape leafworm.
How to get rid of leafworms on grapes
In order not to lose a significant part of the crop, the fight against grape leafworm begins at the first sign of its appearance on the grapes. As a rule, this happens immediately after the swelling of the kidneys. The method of destroying the pest is chosen depending on the life cycle of the pest and the degree of damage to the plantings.
Preparations for leaflet on grapes
The most effective way to deal with caterpillars is to treat them with chemicals from the bunch leafworm on grapes.
Experienced gardeners recommend using insecticides for this:
- Aktara;
- Karbofos;
- Aktellik;
- Spark;
- Inta Vir;
- landing;
- You decide;
- Alatar;
- Ivanhoe etc.
Processing of grapes is carried out before flowering or immediately after that in strict accordance with the instructions attached to the preparation. Spray plants should be in dry calm weather. It is better to do this in the evening, when the activity of the sun’s rays will noticeably decrease.
Given the long waiting period for insecticidal preparations, these agents cannot be used during the fruiting period. In this case, it is better to treat the grapes from the leaflet with biological products such as Fitoverma, Bitoxibacillin, Lepidocide. After the use of such funds, the berries can be eaten after three days.
There are a huge number of insecticides to combat the bunch leafworm.
Folk remedies
With focal lesions, you can use folk methods of dealing with grapevine leafworm.
Spraying the following means will help save the grapes from the harmful activity of the insect:
- Infusion of tobacco ash, for the preparation of which 500 g of ash is dissolved in 10 liters of water and infused for 24 hours. The prepared composition is diluted with water in a ratio of 1 to 2 and the grapes are sprayed with it. For a better effect, a so-called adhesive is added to the working solution, which can be used as laundry or liquid soap (50 g per bucket).
- Celandine with wormwood – to prepare this remedy, chopped herbs (fresh or dry) are combined in equal proportions, poured with boiling water in a ratio of 1×10 and covered with a lid. After the remedy has been infused for two days, it is boiled again, cooled and filtered. The resulting composition is diluted with water in a ratio of 1 to 2, an adhesive is added and the grapes are sprayed.
- Tincture from tomato tops, which is made as follows: 4 kg of tops are poured with a bucket of hot water and left to infuse for four hours. After that, the product is brought to a boil and cooled. The tops are discarded, and the remaining liquid is filtered and used to spray the vine.
Instead of tomato tops, you can use potato
Mechanical method
Mechanical methods are also used to combat caterpillars – they set special traps, remove and burn the affected parts of the plant.
Such methods are quite laborious, so they are not particularly popular.
The use of mechanical methods of dealing with grape leafworm is advisable only in small vineyards.
Prevention
Preventive measures will help to reduce the likelihood of the appearance of a grape leaflet on grapes and save the future harvest.
Experts recommend:
- remove damaged bark in early spring, and treat wounds with a solution of copper sulfate;
- spray grapes with pesticides at the stage of bud swelling and during budding;
- after harvesting, treat the plants with Bordeaux mixture;
- thin out plantings and remove stepchildren;
- clean the soil from weeds in the root zone;
- systematically inspect plants for the presence of grape leafworm and immediately take measures to destroy it.
Ignoring preventive measures can cause serious problems.
Grapes are processed from a cluster leaflet using a sprayer
Conclusion
The bunch leafworm on grapes is a serious pest, the fight against which must be started at the first sign of its appearance. Timely processing of plants will help get rid of caterpillars and preserve the crop.
