Heat-loving Grape Mealybug

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

The grape mealybug is an inhabitant of the southern regions of Russia. In addition to grapes, he is not averse to eating olives, figs, as well as citrus and other subtropical crops. On berries damaged by these parasites, yellowish-brownish specks can be observed. Their dead skin cracks and the berries begin to rot. And if pests populate the berry plantings with a solid mass, then a massive fall of leaves will begin. Females with larvae, in addition to everything, secrete abundant honeydew, on which saprophytic fungi subsequently develop, gradually contaminating berries and leaves with shoots. The most harmful and most numerous is the third generation of gluttonous grape mealybugs

Meet the pest

Females of the grape mealybug are characterized by a wide-oval shape, are painted in yellow-brown tones and grow in length up to 3, 5 - 4 mm. Each individual is quite abundantly covered with a mealy bloom, and eighteen pairs of wax-like thin filaments are placed along the edges of the bodies of the parasites, increasing closer to the rear ends of the bodies.

Females that have not completed their development overwinter in cracks in the tree bark, under the bark, as well as in other protected places near plants. When the air warms up to six to seven degrees in the spring, they wake up and start feeding on the bark of trunks and perennial shoots. Their food usually lasts for fifteen to twenty days.

Since males can be observed quite rarely, the reproduction of grape mealybugs occurs mainly in parthenogenetic way. Pests lay eggs on the shoot bark, and the total fertility of females reaches forty eggs. Females of the second and third generations are more fertile - as a rule, they lay on leaves with twigs from one hundred and fifty to two hundred and fifty eggs.

The embryonic development of harmful parasites takes from eight to ten days. The reborn larvae feed on growing annual shoots for twenty five to thirty days. They also form impressive colonies between the leaves in contact with each other and at the base of the peduncles. And all the larvae of the last generation, which did not have time to complete their development, remain to winter until next spring.

The most favorable conditions for the active life of voracious scoundrels are considered to be the relative humidity in the range from forty-five to seventy-five percent and the air temperature from twenty-two to twenty-five degrees. Crop losses as a result of the harmful activity of these voracious parasites can reach seventy to seventy-five percent.

Grape mealybugs attack completely different grape varieties (they are not an exception and are comprehensively resistant to most pests and diseases). Berry bushes affected by pests lag behind in growth, leaves from them begin to fall off, the bunches gradually dry out, and the berries acquire a rather unpleasant appearance and shrivel.

How to fight

Well helps in the fight against grape mealybugs early spring treatment on dormant buds of awakening crops, which is carried out in order to destroy overwintered females.

You can start spraying with insecticides when three to four leaves are formed on the shoots. During the period of mass appearance of harmful larvae, vineyards are pollinated with 5% anabadust or 1% thiophos dust.

The development of gluttonous parasites is noticeably slowed down by hot summers and rather rainy and cool springs. And in winter, when the thermometer drops below minus fifteen degrees, there is a massive death of larvae.

Also, to reduce the number of grape mealybugs, you can use their natural enemies: predatory beetles of Simferobius and cryptolemus, as well as parasites of cocophagus.