California scale insect is a harmful insect that parasitizes more than 150 species of cultivated plants. In domestic latitudes, fruit trees are most often damaged: apple trees, apricots, pears, cherries. The California scale insect, the photo of which is presented in this material, harms the trunks of plants, and branches, and leaves.
Females
Females are deprived of wings, antennae, and legs; they are distinguished by the presence of a round shield. Such a California scabbard has a size of up to 2 mm. The chitinous shell acquires a shade similar to the color of a fodder plant. In different cultures, the size, length and shape of the body of females can vary. Individuals of this category can be recognized by a characteristic yellowish skin with a white border located in the center of the flap.
Males
The male body has an oval, elongated shape. The length of the shield is from 0.6 to 1 mm. Color - from yellowish and black to light gray. A mature California male scutellum contains a dark transverse strip on the shell.
Unlike females, males have well-developed wings, legs and antennae. Distinguishes their presence of pronounced eyes purple shade. In some regions, males lacking wings are found.
Larvae
There are several forms of larvae of the Californian scale insects:
- A vagabond is a newly hatched individual. It has an oblong-oval body shape, the length of which is from 0.2 to 0.3 mm. It has legs, eyes, a well-developed oral apparatus, the dimensions of which can exceed the length of the body.
- The nymph is the transitional stage of the larva at which the formation of the chitinous shield occurs. The body takes an oval shape. During this period of development, the Californian scale insect changes its color from gray to dark black.
What harm does a scale shield do?
California scale insect is absolutely unpretentious in nutrition. The rapid growth of the population and active reproduction is also facilitated by the absence of natural enemies. That is why the insect has taken root well in American and European gardens.
Scabies are located in numerous colonies on the branches, fruits and leaves of cultivated plants. In the process of development, the larvae suck out the juice from the trees, which leads to cracking and death of the bark. The depletion of plants prevents their growth, causes deformation and reduction of the fruit.
Trees affected by large colonies of scale insects often lose their ability to produce crops, since the main reserves of nutrients are used to restore the structure of leaves and bark.
The fight against California scale insects is extremely important, because plants affected by the pest die even in mild frosts. Actions aimed at protecting fruit trees are taken in early March, when buds have not yet formed on the plants.
Pest Development Cycle
Larvae of the Californian scale insects winter on the bark of branches and trunks, hiding from external influences under strong, well-isolated chitinous shells. With the advent of heat during the turning of the juice, insects awaken and begin to feed. After several links for 20-22 days, the larvae complete the transformation into adults.
Males are active in reproduction by mid-May. Their number is about 10% of the total population. Each female breeds up to 100 larvae within a few months. The latter creep in huge numbers along the branches of trees, stick to the bark and become covered with shields, which act as a natural defense for them.
Having dropped the shield, the males mate, after which they die. In early August, females attach themselves to plants, continuing to consume nutrients, and with the onset of cold weather go into hibernation, becoming covered by a more durable shield.
Signs of damage to plants
The main sign of the appearance of the pest is the formation of light and brownish rounded scales on the leaves of the trees. The latter are quite difficult to separate from the surface. Similar manifestations indicate the presence of adult individuals of the Californian scale insects.
A sign of the spread of pest larvae is the loss of natural shine of tree bark. The defeat of plants by developing insects also leads to the appearance of drips of juice on branches and trunks, and gluing of leaves. Brown and red spots form on damaged areas of wood. In the absence of actions aimed at the destruction of insect larvae, these areas subsequently die off, which leads to a gradual drying of the plant.
California scale insecticide control measures
Destroy the pest by spraying trees. They resort to the procedure when the air temperature at night is not lower than 4 ° C. Otherwise, the liquid in the working composition may freeze.
What kind of chemical kills California scale insects? The trunks and crowns of the trees are sprayed with neonicthionides, pyrethroids, and agents that contain organophosphorus compounds. Processing is carried out by washing the plants. In other words, the trees are completely covered with a liquid chemical composition. Only this approach allows us to count on the complete destruction of larvae and the creation of conditions that impede the reproduction of adults.
Considering how to deal with California scale insects, it is worth noting such an effective remedy as mineral oil. The result of processing cultivated plants with this solution is the formation on the surface of the latter of the thinnest air-tight film. Enveloping trees with such a tool causes the rapid death of the larvae of the insects due to a lack of oxygen. Mineral oils for treating trees are safe for humans. They can be used even if there are ripe fruits on the branches.
A prerequisite for preparing trees for chemical treatment is the preliminary removal of dead bark and dry branches, leaves, basal shoots, thinning crowns. Formed purifications are collected in one place, and then burned.
Finally
So we examined how the Californian scale shield is destroyed. Pest control methods are available to everyone. At the same time, it must be understood that too frequent chemical treatment of trees adversely affects not only the insect, but also the plants, and impedes the normal development of the fruit. Therefore, insecticides are not recommended to be used more often several times a year.
To avoid infection of the garden with insects, you should purchase samples for seedlings only in trusted nurseries. If you need to plant trees in regions where Californian scale insects are extremely common, it is better to give preference to crops that are naturally resistant to pests.
Of particular importance in the fight against scale insects are preventive measures and tree care. Therefore, dead bark, skeletal branches and old trunks must be cleaned in a timely manner, burning the resulting residues. Abundant watering, fertilizing trees, caring for oppressed plants allow them to recover faster from the damage caused by insects.