Scorpion Californian

Scorpion Californian

Pest Type: Fruit Pest

Row: Equine – Homoptera

Family: scale insects – Diaspididae

It is found in the southern and southwestern regions of Russia. In addition to fruit and berry crops, it damages more than 200 species of forest and ornamental plants.

Shields of females are round, up to 2 mm in diameter, gray-brown in color; two yellow larvae are placed in the center of the scute. The female, located under the shield, is 1.3 mm long, round, lemon yellow, with a developed prickly apparatus. Male shield oval, up to 1 mm long. Adult male up to 0.8-0.9 mm in size, light orange in color with a transverse stripe on the chest, with well-developed antennae, legs, and a pair of wings; the oral apparatus is reduced. Larvae of the first age (“strollers”) are light yellow, oval, 0.25 mm long. The larva of the second age – 0.42 mm, similar in shape to the body and color to females, covered with a shield with a diameter of about 0.42 mm.

The larvae of the first and second centuries hibernate under the shields on the bark of trunks and branches. In the spring, with the onset of sap flow, the larvae wake up and begin to feed. In 20-22 days after two molts (end of April-beginning of May) they turn into adult females. In mid-May, males fly out. Their number is small and ranges from 2 to 9% of the population. For 40-60 days, the female revives 80-100 larvae of strollers, which sprawl and stick to the skeletal parts of trees, leaves, and fruits. After suction, they lose their mobility and are covered with wax threads on top, from the weaves of which a white shield forms, which darkens after 3-4 days. 7-8 days after the formation of the gray scute, the larva molts for the first time, after 10-12 days – in the second and the larva turns into an adult female of the second generation. Before the first molt, the male larva develops in the same way as the female larva. Further development occurs with a complete transformation. Coming out from under the shield, the male does not feed and after mating dies. At the beginning of August, second-generation vagabonds and diapausing larvae appear, which leave for the winter.

California scale insects suck the juice from trunks, branches, leaves, and fruits. In the damaged areas, the bark cracks, shoots are bent, leaves are deformed and fall, red spots form on the fruits at the places of sucking. In case of significant damage, the trees weaken and gradually dry out. The pest has a large plasticity range, withstanding temperatures from -35 to +43 ° C and humidity from 30 to 90%.

The number of Californian scale insects decreases the sun, they infect riders from the chalcid family, etc.

Protective measures. Compliance with quarantine measures to prevent the spread of the pest. Cleaning trunks, skeletal branches from dead bark, cutting dry and damaged branches, as well as root shoots, and burning them. If the economic threshold of harmfulness is exceeded: in the cells 2-3 points of infection (0.5 larvae per 1 m of the branch before buds open and 2-3% colonization of the fruit) early in spring on sleeping buds at an average daily air temperature of at least 4 ° C – spraying – flushing suicidal trees; during the revival of larvae of strollers, treatment with insecticides.