Mealybugs - inhabitants of tropical and subtropical regions, which can cause significant harm to protected soil crops.
The mealybug infects various decorative plants, preferring cacti and succulents, it can harm vegetable and fruit crops. The mealybug Planococcus calceolariae is a dangerous pest of citrus and grapes, which can also damage other ornamental plants. Citrus (Planococcus citri), except citrus and grapes, can harm cucumber, eggplant and melon. In addition, citrus mealybug has a second form that damages the roots of plants. Baker's mealybug (Pseudococcus affinis) in the greenhouse can damage cucumber, tomato, gerbera, as well as bulbs of tulips and daffodils during storage. Females and larvae of the mealybug eat on leaves, young shoots and buds, sucking out the juice. On the leaves affected by the wormhole, brown spots are formed. Such leaves twist, can fade and fall off. The nutrition of the pest causes deformation of the fruit, the appearance of cracks in the stems and ulcers, the fall of the ovaries. Mealybugs produce an excess of sugars in the form of honey dew, on which, with its abundant amount, saprophytic sooty smudge can develop. When sporulation, the sooty smudge covers the plant with a black layer, which prevents photosynthesis and worsens decorativeness. The plant infected with a pest lags behind in growth and development, yields little harvest and can perish.
Pest is peculiar to sexual dimorphism. Larvae and females are gray-gray, greenish or pinkish in color, covered with white powdery waxy secretions, which protect them from external unfavorable factors. The shape of the body is oval, ovate or oblong, convex from the dorsal side and flat with the ventral side. Depending on the type of body, there may be 17-18 pairs of wax threads, of which the back pair is often the longest. The size of the adult female in different species differs, and is in the range of 3-6 (12) mm in length and 2-3 mm in width.
Males are smaller than females, they look like mosquitoes with transparent wings and long antennae, on the abdomen there is a pair or a bundle of tail filaments. They do not eat and usually live for several days.
In closed ground males rarely occur, and reproduction occurs by parthenogenesis. Fertility of the female mealybug, depending on the species, ranges from 200 to 600 eggs. After laying eggs, the female usually dies. From eggs appear larvae of the first age (stroller), which actively move in search of a host plant. Stray is the most vulnerable stage of the pest, but it is also the most dangerous, since it helps spread the pest.
Adhering to the plant, the larva passes into the second larval stage and, usually, loses mobility. In the future, only when moving to the next larval stage, when molting occurs, the insect can exhibit motor activity in search of another place of attachment to the plant. After 2-3 (4) moult, the wrecker turns into adult males and females. The pest gives 1-2 (sometimes 3-4) generations per year.
It is important not to let pest penetrate into the greenhouse. To do this, it is necessary to carefully inspect the plants that fall into the closed ground from outside, especially if they are brought from other countries. Plants, entered in the greenhouse, should be for some time in quarantine and not in contact with other plants.
To control mealybugs use predatory bug Cryptolaemus montrouzieri.