Ermine Moth - a malicious pest under a bright guise

Ermine moth is associated with an insect, which should eat the valuable fur of a fur animal from the family of marten - ermine. However, despite the name, the appetites of the moth are much more modest. Depending on the species, it is content with apple trees, bird cherry. The most harmful species in the post-Soviet space is considered to be an ermine apple moth, as well as a fruit moth that is similar in morphological characteristics and lifestyle. For what gardeners of these insects do not like so much, what harm they cause and how to resist their invasions - let's understand.

Appearance

Ermine moths are representatives of the family Lepidoptera Lepidoptera. In total there are about 600 species. Most of them live in the tropics. In the CIS countries, 50 species have been recorded, from which mainly the southern regions suffer.

On a note! In Russian taxonomy, moths include all small moths, which are distinguished from club-shaped butterflies by the absence of a proboscis, the specific folding of wings and activity in the evening. In English terminology, the moth category includes both small and large moths, including silkworms.

How to recognize ermine moth among other moths

The insect stands out from other pests due to its appearance:

• the length of the body of an adult does not exceed 2 cm, the wingspan varies from 16 to 22 mm;
• front wings of a female of snow-white color with silver tint with contrasting black spots arranged in three rows; if you carefully look at the photo of the ermine moth, you can count about 20 inclusions on each wing; for its original appearance, the moth has earned its name;
• males have front wings of a darker color, even brown, and have a characteristic rounding, reminiscent of the half of the moon;
  
• hind wings of ash-gray smoky color, bordered at the edges with white long fringe and slightly rounded;
• the head is crowned with a filiform tendrils, the dimensions of which are only half the length of the trunk;
• a distinctive feature of all ermine moles is hairy scales on the head, pressed on the forehead and sticking out on the crown like a crest.

Sexual dimorphism is inherent in insects. Females are larger and lighter in color. The structure of the genitals is also different. In females, the ovipositors are slightly noticeable, and in males it is pronounced. Interestingly, in the mating season, males give out a special secret to attract females. For people, its aroma seems too harsh and specific.

What does the younger generation look like?

Oval yellow eggs of tiny sizes are protected by a kind of flat shield of a honey hue, the dimensions of which are 4-5 mm. Over time, it becomes red, and subsequently brown, and merges with the bark of trees.

Larvae of ermine moths are less attractive than adults and are fleshy yellow caterpillars with a brown head.The young individual undergoes three molts and, as an adult, becomes gray-yellow in color with noticeable black dots on its back. Its length reaches 16-18 mm.

The final stage of development is pupation, which takes place on the same tree where the larvae developed. Just started the process, the pupa is saturated orange 10 mm long. Subsequently, it acquires a greenish tint with a clearly distinguishable brown head.

Lifestyle

Insects spend the winter in the caterpillar stage of the first age under the shield. With the onset of heat, after the apple buds have blossomed and the temperature has set below 12 ° C, they leave their shelters and bite into the leaves. Young larvae gnaw only the upper part of the foliage, eating away all the flesh. The upper and lower parts of the skin remain. Damages of this nature are called mines.

Larvae need active replenishment of nutrients and are very voracious. After the leaf has exhausted the resource of juicy plant tissues, the caterpillars migrate to the adjacent leaf.

The exit from mines and the transition to the next stage of development begins in late April, early May and, as a rule, coincides with the beginning of flowering apple trees. During this period, the caterpillars hold in groups, dine the outer parts of the leaves and entangle everything with a cobweb, creating their own nests in it, while gluing the leaves in pairs.

The number of cobweb nests is increasing rapidly, the larvae are taking over new territories and as a result, the tree can be completely entangled in cobwebs. Damaged mined leaves that are in the focus of infection become brown and fall off.

Interesting! Caterpillars begin their movement from the top of the branch, gradually moving to the base. On their way, they completely destroy the leaves, leaving only veins from them.

The nutrition period lasts 35-42 days. Dry or hot weather is most optimal for the development of larvae. Having collected the necessary amount of nutrients, having undergone molting, the adult caterpillar weaves a white cocoon, which is located right there in the nest. The larvae pass into the pupation phase simultaneously, therefore, in the nest, one can observe a large accumulation of cocoons tightly pressed to each other.

Pupae develop from 1 to 2 weeks, after which adult ermine moths blindingly white with characteristic speckles fly out of them. The life expectancy of adult moths is about a month. You can observe their years from late June to late July – early August.

On a note! Most adult moths do not eat anything and exist due to accumulated nutrients in the larval stage.

How motley moths breed

In the daytime, ermine moths hide under the leaves, peak activity occurs at dusk. 2 weeks after hatching from pupae, mating begins. After fertilization, the female begins to lay eggs in 5-6 days. She places them in groups that are tiled in the immediate vicinity of each other. The female covers the eggs with mucus, which after solidification forms a kind of shield. The total fertility of a female is from 20 to 100 eggs.

Embryonic development lasts one to two weeks, after which caterpillars of the first age appear. Initial nutrition consists of egg shells and tree bark. Larvae do not leave the scutellum and remain under it for the whole winter, which they spend in diapause. With the advent of spring, the caterpillars awaken and begin their wrecking activities.

Why are ermine moths dangerous and how to deal with them

The ermine apple moth causes harm, being in the larval stage. If the caterpillars destroyed up to 25% of the foliage, then the risk for the tree is negligible. It may well recover. But if glutton-larvae have completely eaten the foliage, it is likely to remain not only without the crop, but also the tree itself.

To combat apple moth, chemical and biological preparations are used, as well as mechanical methods of killing the pest:

• Spraying trees (with the exception of the flowering period) with organophosphorus preparations, as well as agents based on pyrethroids, neonicotinoids. The first treatment is carried out immediately after flowering, and the second, as soon as the years of butterflies were noticed.
  

  On a note! During the ermine moth invasion in Irkutsk, the sanitary services recommended that Aktellik be treated with trees. Processing one plantation with this drug will cost about 200 rubles.

• Manual collection of cobwebs with subsequent burning, molding trimming crowns from dried branches.
• The use of pheromone traps, which contribute not only to capture males, but also allow you to determine how large the population of ermine moths is.