What is the danger of the American white butterfly and how to protect your site from it?

One of the most dangerous insects for agriculture - the American white butterfly, which has distinctive gluttony - at first glance is completely unlike an insidious pest. But, getting to know her better, it becomes clear that such an enemy should not be underestimated, so as not to be left without a crop. A set of measures to exterminate the butterfly will help to cope with it if necessary. Fortunately, it is not very common.

Insect description

The American White Butterfly is a quarantine pest whose Latin name is Hyphantria cunea. She belongs to the Dipper family. The taste preferences of the winged pest are quite extensive: according to biologists, there are about 230 species of trees, shrubs and herbaceous plants in the “menu” of butterfly caterpillars. But they give preference to plantations in the garden - fruit crops. This is due to the large negative impact of the "American" on agriculture.

Quarantine pest - an organism that is absent in the territory of the state or located on it in a limited amount, but harmful to plants.

Judging by the name, it is easy to guess that the historical homeland of the American butterfly is North America, where it is spread from the lands of Canada to Mexico. On the neighboring southern continent, the insect was chosen by Colombia.

The spread of butterflies in the Old World and Asia began in the middle of the last century, namely in 1949, when it was seen in Yugoslavia. Very soon, the real invasion of the American white butterfly on Eurasia began, because it partially settled from the Caspian to the Atlantic. In 1952, a pest was discovered on the territory of Ukraine in Transcarpathia, and soon appeared in the southern regions of Russia and the Central Asian republics.
Biologists note that the butterfly spreads around the world mainly during the transportation of goods, primarily with the harvest of berries and fruits. The pest also moves in vehicles, with containers and packaging material. If the final point for the American white butterfly is favorable, then it begins to breed and destroy the plants.

Appearance

The wingspan of males of the American butterfly is 2.5 cm – 3 cm, which is less than that of females: in females this figure can reach 3.6 cm. Although this insect cannot be called large. Butterflies feature a snow-white coloration of wings and torso. The latter has a long pubescence, due to which the insect seems fluffy. Some individuals on the wings have a scattering of black or brown spots of small diameter. The antennae of the butterfly are black, with a slight whitish bloom. In females, they look like smooth threads, and in males they are comb-like.

Female specimens that have not yet made masonry have an abdomen with a green tint. It appears due to the scintillation of eggs.

Development phases look like this:

1. The caterpillar of the American white butterfly, just born, is painted yellow. In this case, the head, chest shield and legs are slightly darker.On the surface of the back 2 rows of black or yellow warts of small size with black and white hairs pass, and on the sides - 4 such rows.
2. In the last stage, the caterpillar acquires a brown color. The warts on the back are black, on the sides of the body are bright orange, from which long dark hairs come out. The length of the body of the caterpillar is up to 4 cm.
3. The doll of the American butterfly is brown, located in a cocoon of gray. The length is approximately 1.5 cm. The body ends with spikes: their number is from 10 to 15 pieces.

A snow-white imago appears from the pupa.

Butterfly life

The American butterfly waits for the winter in the form of a chrysalis, finding shelter from seasonal weather. It climbs into the crevices of houses, into cracks in the bark of trees, into broken branches and other suitable corners. The insect will get out of its shelter only in the spring, when the apple trees begin to lead. The main activity of butterflies occurs in May and June. From the time of day, they prefer night, starting to fly after sunset over the horizon.
After mating, the females lay their eggs on the back of the leaves. In all, she can lay 1,500 eggs in her life. 2-3 weeks after the masonry is created, caterpillars appear. They will turn into a chrysalis from 30 to 50 days, while eating plant leaves.

The duration of the development phases of the American butterfly directly depends on climatic conditions. The optimum temperature is 20–25 ° C and humidity 70–80%.

At the end of July and August, butterflies of the “summer generation” are born, which are very active in the morning and night hours. They differ from the "spring" in increased fecundity: females lay 2500 eggs, of which caterpillars appear in September. Pupae remain in the shelter for the winter.

The American white butterfly is characterized by the implementation of two generations per year.

What harm does an American butterfly do?

Biologists note that all plants damaged by the American white butterfly can be divided into 3 large groups:

1. “Favorite”: apple tree, plum, cherry, quince, ash. Become the victim of a pest most often.
2. Providing butterflies with a complete transformation cycle: deciduous (shrubs and trees).
3. Unable to provide the full cycle: conifers and grasses. They are attacked only by already grown caterpillars.

Thus, most plants grown by humans may be at risk.

The damage to plants caused by the American white butterfly is as follows:

1. Destruction of plant leaves by caterpillars, which, of course, causes him irreparable harm. Young caterpillars eat the meaty part, rich in juice, leaving a kind of core from the veins. The grown individuals are able to cope with him, without leaving a trace from the leaves. This process continues until the fall.
2. The plant cannot develop normally. Its appearance suffers, productivity decreases significantly. If you do not take measures to combat the American white butterfly, then it may completely die.
3. Caterpillars tend to live in colonies. Gathering in heaps, they braid the branches of trees and shrubs with cobwebs. When neglected, such a halo surrounds the plant completely.
4. Landings attacked by an American butterfly are very weak. They hardly survive frosts.

Of course, one cannot fail to say about the amazing speed of spread of the American butterfly. If she appeared on the site, then soon all the nearby territories in the district will become infected.

Ways to fight

How to deal with the American butterfly? There are a number of special measures that indirectly help to prevent the appearance of an uninvited guest or reduce its population:

1. Quarantine measures: inspection of supplies, new seedlings, etc.
2. Landing monitoring.
3. Removing dead bark from trees in which pest pupae can hide in anticipation of spring heat.
4. Destruction of excess and dry branches.
5. Regular weeding from weeds on the territory;
6. Plowing aisles between trees and shrubs in the fall.

But these measures are more prevention than a way to combat. There are special remedies for the American butterfly that help to destroy it and save fruit and berry crops.

Chemicals

Drugs against the American butterfly should be used with caution because they are toxic. It is very important to observe safety measures. But these tools show good results:

• Antio
• Durbasan
• Zollon
• "Metaphos";
• Nitrafen
• "Phosphamide".

You can also use systemic insecticides such as Aktara or Karate. They are applied to trees by spraying their garden spray gun before flowering, so as not to harm the future crop.

It is necessary to treat not only the affected trees, but also all plants located within a radius of 50 m. The consumption rate is indicated in the instructions for each drug and depends on the concentration of active substances in it.

Other means

The most primitive way to destroy a butterfly is to mechanically collect the tracks. They are easy to spot on the leaves. It is more effective to do this at night or after the rain has passed, because at this time the caterpillars gather in flocks.

On an industrial scale, biological control methods are often used - the use of viruses and microorganisms that kill the American white butterfly.

You can also make traps from black hoses immersed at one edge in a barrel of water. Caterpillars love moisture and heat, and they will certainly climb inside to pupate. Therefore, in 3 days it will be possible to destroy the prey.

An effective way to combat the American butterfly with folk remedies is a trap with beer or kvass. For caterpillars, such drinks are a treat. Therefore, if you hang a small container with a treat on a tree branch, after a few hours the pests will be trapped.

To exterminate the pest in its area, you need to use a set of measures. The use of folk remedies alone will not be enough. When the American white butterfly is driven out of the garden, it is necessary to constantly follow the rules of prevention.