We Fight With Grape Speck

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

Grape mottles live mainly in the south of the country and harm the harvest of juicy grapes. The main harm in the spring is caused by voracious caterpillars, affecting delicate buds during their swelling, as well as at the stage of blooming. The result of the destructive activity of grape variegates is often significant yield losses. Moreover, both individual shoots and whole bushes can die

Meet the pest

The variegated grape is a butterfly whose wingspan ranges from 22 to 25 mm. From above it is either blue-green or blue.

The size of the eggs of the grape mottles is 0, 4 - 0, 6 mm. They are yellowish, oblong and decorated with a very bizarre mesh pattern. The length of light gray caterpillars is 16 - 18 mm. On closer inspection, four rows of brownish warts with tufts of orange hairs can be seen along their bodies. Pupae of the gluttonous grape mottled are yellowish-gray, 11 - 15 mm in size. And on each segment of these pupae there are dark dots.

Caterpillars of the second or third generations hibernate in dense cocoons or in cracks on the stumps and trunks of grapes, or under peeling bark. Much less often they go to wintering in plant debris. And when the buds begin to swell in the spring, the pests will climb the grape bushes, bite into the tender buds and begin to eat away their contents. Having eaten enough, they move to young leaves, in which they gnaw out the parenchyma from the lower sides, leaving only the upper cuticle. And the caterpillars of the latest generations are already gnawing through holes. During the period of their development, they manage to shed as many as five times. The parasites are especially active in the morning and afternoon, hiding before sunset. Ripe caterpillars fall to the ground, curling into rings. Parasites pupate at the beginning of flowering of grapes in cocoons in the upper soil layers, under fallen leaves or under peeled bark.

Two - two and a half weeks after pupation, butterflies begin to appear. These butterflies do not feed at all, but simply lay eggs on the undersides of the leaves in fairly solid groups - ranging from several dozen to two hundred. The total fertility of females reaches an average of 400 - 600 eggs. After 8 - 10 days, the revival of harmful caterpillars occurs, which will feed on leaves until the second and third centuries, and subsequently, somewhere in August, will go to wintering places. During the year, only one generation of grape mottled has time to develop.

Mass reproduction of these gluttonous parasites is focal in nature. This is due to the fact that harmful butterflies are not able to fly over long distances.

How to fight

Spiders, larvae of sirfid flies, predatory bugs, coccinelids and ground beetles help to a large extent to reduce the number of grape mottles.

During the pupation period of caterpillars, appropriate soil cultivation must be carried out. Moreover, the soil must also be cultivated in the aisles. And tree trunks should be cleaned of dying bark. An important role is played by the correct pruning (in particular, by the diaphragm), as well as the formation of bushes on the wire along the trellis system.

If the number of voracious caterpillars begins to exceed two or three individuals per bush, they switch to spraying with insecticides or biological products. Often, insecticides such as "Antio", "Zolon", "Phosphamide", "Actellik" and a number of others are used against this pest. Focal treatments by them will be quite enough.

The first spraying, as a rule, is carried out during the swelling of the buds, the second - when the buds open, and the third spraying will be appropriate when the next generation caterpillars appear. A month before harvesting, all treatments are stopped.