Phyloxera Grape - The Enemy Of The Harvest

2024 Author: Gavin MacAdam | [email protected]. Last modified: 2023-12-16 13:38

Phyloxera grape is found mainly in the western and southern regions of Russia. This pest came to Europe in the 60s. XX century. from America. There are two types of phylloxera - leaf (gallic) and root. These varieties are due to harmfulness and lifestyle, but both of them are capable of causing quite serious damage to the grape harvest

Meet the pest

Females of root phylloxera are oval in shape and reach a length of 1 - 1, 2 mm. Their color is yellowish-brown or greenish. Harmful females are endowed with a long proboscis and antennae with three segments extending behind the base of the hind legs, and on the upper parts of their bodies there are rows of warts - as many as seventy pieces.

Females of the leaf phylloxera, in comparison with females of the root variety, are more rounded in shape and have a yellow-green color. There are no warts on their bodies, and the proboscis of these pests is short.

There are also intermediate varieties of phylloxera. These include winged nymphs, as well as bisexual (amphigonic) individuals.

Younger larvae are colored milky yellow and reach a length of 0.3-0.4 mm. The intestine of this pest is closed, digestion is extraintestinal, and the anus is completely absent.

On Asian grape varieties, and on European ones too, the reproduction of phylloxera is observed only on the roots. And on American varieties and on a number of hybrids, these parasites can successfully develop not only on the roots, but also on the leaves. At the same time, they go through the entire cycle of their development.

The first generation larvae overwinter mainly on the roots. Sometimes their second generation also hibernates there. They begin to wake up from the winter torpor as soon as the temperature reaches 12-13 degrees. The harmful larvae immediately begin to feed, and twenty to thirty days later they turn into the so-called parthenogenetic females, characterized by the complete absence of wings. Having laid about 50 - 100 eggs, these females die. Reviving harmful larvae, having passed as many as five instars, turn into exactly the same females. Thus, during the season, from five to eight generations of parasites can develop in the ground. In the summer, one generation develops in about 18 - 26 days.

A certain part of the larvae, called tramps, getting out onto the soil surface, through cracks in the ground, freely gets to the roots of nearby bushes. The annual cycle of the root form ends with the fact that the larvae of the first (and sometimes second) instar with the arrival of September-October go to winter.

Part of the larvae of the third and fourth instars, starting from mid-June, form nymphs, which, after emerging from the soil, are transformed into winged females that do not feed at all. And they lay eggs on the ground parts of grapes in an amount of 1 to 4 pieces. The eggs laid by them, as a rule, are of two types: small (0.25 mm each) and large (up to 0.4 mm). From small ones, males are reborn, and from large ones - females. Mating females lay one wintering egg in the cracks of the wood and die immediately after that. And in the spring, leafy phylloxera is reborn from these eggs, which subsequently moves to the blossoming buds and immediately sticks to the upper sides of young leaves of American and hybrid varieties of grapes. On Asian and European varieties, the larvae do not have the ability to stick to the leaves, so they die.

How to fight

To prevent the appearance of phylloxera, it is very important to choose the right soil. Its destructive activity is not favored by sandy soils containing no more than five percent of clay particles, as well as their density not exceeding 34%, and moisture capacity - 20%. In the event that there are not very many phylloxera on the leaves, the affected leaves can be torn off and burned.

The entire territory in which grapes are grown is usually divided into three different zones: a pest-free area, and also in the area of partial spread of the parasite and continuous settlement. In the first zone it is recommended to grow own-rooted varieties (this is for the majority of European grape varieties). Periodically, in order to protect against pest attacks, various quarantine measures are carried out in this area. And in the second and third zones, a chemical method is used to eliminate phylloxera located in the soil. A good effect is given by an emulsion of carbon disulfide and hexachlorobutadiene. In case of severe parasite infestation, spraying with "Kinmiks", "Fozalon", "Fastak" and "Aktellik" is carried out. The first treatment with them is usually carried out after bud break, but before the formation of second leaves on the shoots.