Diaspidiotus perniciosus Comstock

 

        Diaspidiotus perniciosus Comstock is a pest of fruit plants, as well as ornamental and forest plantations. For the first time this Jose scale of his homeland of China and Japan was brought to California, where caused great damage to the fruit USA. With plants pervasive and so acclimatized. In Russia Diaspidiotus perniciosus scale appeared in the early twentieth century. At this time, spread around the world. In many countries in Europe, Asia and Australia harms fruit trees.
        California scale is polyphage infects intense fruit, berry, ornamental and forest plantations. Causing  enormous damage to apple trees.
        In Azerbaijan, this Diaspidiotus perniciosus  scale damages apple, pears, peaches, cherries, walnuts, currants, rose hips, sage, lilac, willow, poplar, dogwood, from decorative rose, the color of acacia and others. Mainly develops on the shoots, stems, leaves and fruits, cause great damage. In such a way, trees weaken, on the trunks of the formation of various injuries and dies as a result of the bark, the leaves prematurely fall down, twigs deformed fruits are not fully developed. In fetuses infected spots appear strongly damaged trees die completely.
        Epiphytotic California scale development of explained by the fact that it is very fruitful (born larvae are in large numbers, the number of generation 2-3, sometimes, and 4) a polyphagous, from an environmental point of view is very plastic. With strong infection fruit damaged and their storage is not possible, they quickly are rotting. Taste of fruits changes, decreased vitamins and sucrose added acidity.
        Adult females of the scale insects have a circular shape with a diameter of 1.5-2 mm, slightly convex, the middle of a dark gray on the sides of light. Body size, depending on the plant organs are different. The young apple and pear scale insects living in diameter are more than the fruit. At the leaves size of individual females are smaller. The body is round, lemon-yellow color. Mouth parts piercing-sucking and very well developed. Adults females orange have one wing, antennae consist of 10 segments, has a well-developed third pairs of legs. Females elongated shield, and they also color as males. Larvae lemon-yellow color, very active, have 3 pairs of legs and one pair of antennae, actively moving. Mouth parts well developed. Larvae after active movement glued to the plants. Produce white waxen filaments and form a "white shield", after 3-4 days the shield darkens and turns gray shield.
        After attaching to the plants, after 8-9 days the larvae molt. During this process, the larvae lose limbs, eyes and antennae. Then the larvae are formed II age. These larvae observed sexual dimorphism. During this period the larvae are smaller females than males. Shields male pear-shaped and they grow slowly, males formed reddish eyes. Females under the shield whirl and move only so formed rounded shield. Males do not move, they formed a shield in the direction of the end of the body, elongating. Period before molting males called pronymph. After molting they are named nymphs. In nymph observed well-defined eye. Lays the groundwork limbs, antennae and wings.
        Nymph the scale insects yellowish color, size 1 mm. Have well-developed antennae, legs and wings. Within 4-5 days develops individuals, then there is molting. Adult males emerge from under the shield. Wintering larvae differ from the larvae of the 1st age. They are larger in size and have dark black shield. California scale overwinter in the larval stage I age. Awakening in wintering larvae begins at 8-100S. At a temperature of 100C in the larvae molt begins the age of 1. Usually this scale insects molt begins after 12-15 days. In Apsheron molt begins in late March, early April. In the second decade of April appear II age of larvae. In late April, early May, males hatch. The mass departure of males observed in the evening. After fertilization, the males die. One male can mate with 6-8 females. Larval development lasts for 30-40 days. In the late May 10-15 days after mating there are viviparous females. These females within 30-40 days give rise to larvae, then twisting die. Males live for one day and then killed. Appears when the larvae live birth through 25-28 days turn into larvae II age where well marked sexual dimorphism. After 14-16 days of development, begins departure males. After mating, the female, the latter are formed inside the egg.
        After the embryonic development in females appears 3rd generation.
In II and III decade of June the larvae appear III generation. In II and III decade of September there are females of 4th generation. With cold weather in California scale observed individuals of all ages. But the cold accelerate their death, only I remain larvae age. Being in the stage of diapause larvae adults hibernate. Life expectancy and development of larvae California scale depends on abiotic factors. In Apsheron on apples in 2005 the survival rate was 65%, and in 2006, the larvae of I instar survival was 52%. The larvae of I instar diapause begins. In Apsheron in late July, early August, some of the larvae development is suspended. They begin diapause. These larvae size larger than the larvae passing development, and shields are darker in color. Number of diapause larvae passing is 40-45%. The possibility of hatching females,California scale depending on the plant species on which it resides, as well as the areas of distribution. In hibernating females the opportunity birth larvae compared to the spring and summer is low.
        According to our observations revealed that in a pear tree female gives birth to one fish larvae 220-230, 170-190 pieces of almonds on a plum tree is even smaller pieces 140-150. Minimally females born larvae of 100 pieces, the maximum is 250 pieces. California scale reproduces sexually, another way of reproduction they are not marked.

     

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