Phyloxera on grapes - is the devil so terrible?

Many troubles came to us from North America. If everyone knows about the Colorado potato beetle and about the harm that it causes to numerous potato plantations in our country, then mainly vine growers know what phylloxera is.

And this is not surprising, because not even in all vineyards vines are damaged by this quarantine pest. but if you see strange plaques and swellings on the surface of your leaves that look like sores, then you should know that this is probably not a grape disease, but a phylloxera.

In the photo, the phylloxera looks like small dots on a leaf. But this is only the top of the picture. The same sheet below looks much more pitifully.

It is natural that the leaves affected by the pest cannot work with sufficient efficiency for the overall development of the plant, as a result of which the vine loses in productivity, and may even die.

Biological characteristics

Meanwhile, phylloxera grape is a very interesting creature from the point of view of biologists. This insect has several species, which are divided into three broad categories:

• aboveground, or leaf, which were presented in the upper pictures;
• underground, or root, which parasitize on grape roots;
• intermediate, they are also called settlers.

This allows the insect to lead a somewhat peculiar life cycle in which not all stages of development are constant. Consider this phenomenon in more detail.

Food

Despite the difference in living, the leaf and root phylloxera of grapes eat only parts of this plant. Therefore, with the death of the vineyard, these pests will also die due to lack of nutrition. In this regard, this insect is an example of a typical monophage.

Reference! Monophages are animals that feed exclusively on one type of food.

The root forms of the insect suck the juices from the finest villi on the roots of the grapes. Leafy species suck juices from the leaf plates of a grape bush, forming growths, the so-called galls. Therefore, leaf phylloxera is also called gall aphid.

Polymorphism

This term refers to the variety of forms of the same animal, depending on the stage of its development, gender and age. In phylloxera, such generations are observed:

• Female root form. A wingless creature 1-1.2 millimeters long in greenish or yellow-brown hues. Has a long proboscis
• Female sheet form. Small aphid half a millimeter long with a short proboscis and a dirty yellow cover.
• Larva of the first age. Lemon yellow short body 0.35 millimeters long. Digestion in the larvae is external; it absorbs food digested under the influence of the juice secreted outward.
• Female settler. Unlike other species, it has wings and is distinguished by its large size compared to other forms of phylloxera. The body length of this generally asexual female reaches a millimeter and a quarter.
• Bisexual generation. Biologists call this term males and females phylloxera, which are directly involved in the reproduction of offspring. The length of males does not exceed a quarter of a millimeter, females - 0.4.This form of insects has neither wings nor proboscis for feeding.

Reproduction and development

Phylloxera propagation proceeds in several directions, each of which has its own characteristics. Scientists have found that in the process of development, all types of phylloxer can pass into others.

Root phylloxera

Larvae of this species winter underground at a depth of up to three meters. With spring warming of the soil up to 13 degrees Celsius, they begin to intensify nutrition, sucking juices from thin roots of the grape bush. Within 15-25 days, they eat off and turn into females of two species: the underground root and winged settler.

The root female breeds parthenogenesis, it is able to lay from forty to one hundred eggs. During the summer season, four to eight generations can occur depending on the living conditions of the root phylloxera.

Reference! Parthenogenesis - the possibility of asexual reproduction by cell division.

Females settler

Climbing to the surface and gaining wings, these females are easily transported under the influence of wind and with the help of wings to decent distances. Having clung to a bush of grapes, they are able to lay several eggs on the bark or leaves of the plant, most often 2-4 pieces. Some of these eggs are small, and some are large. Subsequently, males appear from small testicles, from large females, which form a bisexual generation.

Gender Generation

Hardly hatching from eggs, males and females of this form phylloxera mate, and the female lays only one egg on a section of a stiff trunk or a stem part of a vine. Egg overwinter.

Leaf females

In spring, larvae of leaf-shaped females appear from eggs laid on the stem. They move to the surface of the leaf and begin to feed, forming galls.

Immediately, directly in the galls, the larvae turn into a female, which lays from 250 to 500 testicles. After eight to ten days, new larvae emerge from the eggs, which creep along the leaves, forming new swellings.

In total, the leaf phylloxera generates up to nine generations during the season. Starting from the second generation, an interesting metamorphosis begins to occur - in some larvae the proboscis lengthens. These larvae move underground, where they then turn into root insects. Thus, the mutual reformatting of the phylloxera species occurs.

Maliciousness and fight

Before you begin the fight with phylloxera, you must also understand such a feature of the insect in combination with grape varieties. The fact is that on American grapes of the Vitis riparia type, plant roots are resistant to phylloxera. At the same time, in European and Asian varieties, as well as American varieties of Vitis Labrusca, resistance to phylloxera is observed in leaves.

Based on this knowledge, breeders are developing new varieties and hybrids that become “too tough” to a dangerous pest. In particular, many European varieties resistant to leaf race are grafted onto "American" stocks.

Unprotected grape bushes are very affected by the phylloxera invasion, which can take several years to cure the effects of an attack. In some cases, you even have to cut down the vineyards to clear the land of the pest.

Quarantine measures prohibiting the import into certain territories of certain grape varieties particularly affected by phylloxera become very effective.

Used in the fight against phylloxera and chemicals, for example:

• pyrethroids;
• organophosphorus compounds;
• neonicotinoids.

These drugs must be diluted in accordance with the instructions for use and spray the plants on a leaf.

Attention! When preparing chemical solutions, make it a rule to slightly reduce the dose of the working substance. Excess concentration can destroy an already weakened pest plant.

For the root phylloxera, this method is used.The soil is treated with carbon disulfide, which in an increased concentration kills not only pests, but also plants. A small dose, up to 70-90 milliliters per square meter with a small defeat, can save the vineyard.

The safest way to control pests is to use biological fungicides. One of them is the now popular Fitoverm, prepared on the basis of the bacteria of hay bacillus. This drug immediately performs a double help to the plant: it destroys pests and restores the plant's immunity.

In today's video report, you will see how an experienced wine grower fights grape phylloxera in his area with his own methods.