In article there is a speech about the dangerous quarantine wrecker – the American white butterfly, her morphological and biological features, habitats, terms of development and ways of distribution are given.
From fight methods the author recommends to hold destructive events which provide use entomofagov and biological and chemical preparations. Application of agrotechnical actions isn’t excluded also.
AMERICAN WHITE BUTTERFLY
American white butterfly (ABB) dangerous quarantine wrecker, polyphage. It damages more than 100 types of tree, shrubby species and about 100 types of grassy plants. The most damaged from them a mulberry, the American maple, a quince, an elder, a cherry, a pear, grapes, a walnut, plum, hop, an apple-tree.
Morphological and biological features.
Butterflies in wingspan of 25-36 mm, length of a body of 9-15 mm. Wings snow-white, brilliant, at some individuals on forward wings dark brown points. The head, a breast, feet and a paunch are covered with white cheshuyka. Short moustaches black and white dusting. In a form short moustaches at females threadlike, at males the plumose – a sign on which it is most easier to distinguish a male from a female, pads orange-black. The paunch of the females who yet haven’t postponed eggs, greenish from appearing-through eggs, after their otkladka it is reduced in volume and loses green color.
Eggs spherical, with a close-meshed sculpture, the size to 1 mm, golden-yellow or green. In process of germ development their color gradually changes and becomes gray and tin. Eggs are postponed by groups, on some hundred pieces, as a rule, in one layer for the bottom party of leaves. Their laying is usually covered with a white down from a paunch of a female.
Caterpillars of younger age in length from 2,0 to 6 mm, light yellow with the black head, a chest guard and feet. the senior – from 18 to 36 mm, velvet-brown from a back, with black warts and long black hairs, from sides – with yellow warts and white hairs. These hairs create a plentiful opushennost of caterpillars, characteristic for this look. On a back black spots merge in black strips. Head of a caterpillar of brilliant black color.
The caterpillar has three pairs real chest feet and 5 pairs of false belly. Chest feet long, black color, false – high, cylindrical, with numerous small hooks on the end by means of which the caterpillar well keeps on plants even at rather strong wind.
Doll from 10 to 15 mm of length, 3-4 mm of width, at females, as a rule, more than at males. Form of dolls veretenovidny. Color dark-brown. On the end of the last belly segment is available from 10 to 15 stupid thorns. The doll is concluded in a friable gryaznosery web cocoon.
The doll in a friable gray cocoon from caterpillar hairs in cracks under a bark of trees, in dry leaves, vegetative garbage, cracks of houses, fences, in the soil winters. The main part of dolls remains in the soil on depth of 3-5 cm some – on depth 15 see. Naturally they transfer temperature to – 30°S, but are very sensitive to sharp fluctuations of temperature in a wound – the spring period. Otrozhdeniye of butterflies begins at the end of April or at the beginning of May, and summer generation – at the end of July at the beginning of August. Butterflies don’t eat.
In search of the sexual partner and a place from a laying of eggs the female flies by distance of 250 m. After pairing in 1-2 hours the female starts to postpone eggs for the bottom party of a leaf, mainly top branches (in a peripheral part of krone), attaching a yaytsekladka a secret. Even the heavy rain can’t wash away it. Each female is capable to postpone for 1-2 days from 400 to 800 eggs on the average. The maximum of postponed eggs makes to 1800 pieces. The most active years of butterflies is observed at o’clock at dawn.
In 10-14 days from eggs otrozhdayutsya caterpillars. The caterpillar during development passes seven age. In 1-2 hours after an otrozhdeniye it starts a food which is accompanied by web allocation. The nest of caterpillars of 1-2 age covers some leaflets, caterpillars live a colony. With growth their web nest increases in the size from top to down on a tree branch.
When on a tree otrodilis caterpillars from several layings, web nests can be closed, forming the continuous veil of a web shrouding a tree. Nature of damages with growth of these wreckers changes. Caterpillars of the first and second age scratch out epidermis from the bottom party of a leaf, leaving untouched its top surface. The caterpillar of the third age can put the same damages on breeds of the plants having a thick plate of a leaf (an apple-tree, plum), or make holes in a sheet plate, if it thin, such as, at a maple yasenelistny. At the fourth age of a caterpillar depending on quality of a leaf or make in it larger openings, leaving untouched veins, or gnaw round a leaf plate from edges. Upon transition to the fifth age they gnaw round sheet plates from edges together with lateral veins, and caterpillars of the sixth and seventh age quite often eat a leaf entirely. Soskablivaniye cases for caterpillars of a thin skin of fruits – apples, pears and plums are known.
These wreckers having reached the first and second age keep in a small web nest one colony. With transition of caterpillars to the third age their some dispersal within the general web nest is observed. Having passed to the fourth age, caterpillars keep several groups, but still in the general nest; when cutting such nest they keep in a web, without dropping out of it. Caterpillars of the fifth age live in a nest small groups and at this time web allocation stops or decreases; when cutting such nests the part them falls to the ground even from a small sotryasaniye of a branch.
At caterpillars of the 5th age the nest can reach the sizes of 1-1,5 m. In it time they creep away from a nest on all tree. After a molt at the sixth age in a web nest meet less often, more often they can be met on some pieces on sheets. Caterpillars of the seventh age creep away on all crown and live one by one.
To know nature of damages and web nests of the American white butterfly it is necessary for recognition and identification of nests of the wrecker at inspections. To form web nests and to live in them caterpillars of the four first age begin with transition to the fifth age. This moment has big practical value in system of actions for elimination of the centers of this wrecker. In particular, mechanical fight can be carried out only when caterpillars are in a web nest.
Duration of development of this wrecker makes 35-45 days, development of the first four age lasts 18-21 day. At a lack of food on one tree of a caterpillar migrate on other tree. Young eat in one day of food at 5-10 times more weight of the body. Especially gluttonous they become, having reached the sixth or seventh age; during this period they eat so much food, how many by them was eaten during the previous five age.
Caterpillars of advanced ages, being less legible to food, damage grassy plants, garden and field cultures. Before an okuklivaniye they forms round itself a web cocoon into which long hairs of a body are interwoven; by this time the body of a caterpillar is shortened and utolshhaetsya. Web cocoon of gryaznosery color, 1,5-2 cm in length, oviform. Caterpillars pupate more often in masses in one place. In a cocoon their thin skin bursts lengthways on the dorsalny party of a body. In some hours the doll becomes brilliant and gets dark brown coloring.
Development of a doll of the first generation in the conditions of the Crimea lasts 14-20 days, depending on environmental conditions (temperature, humidity) and from their physiological condition.
Habitats of the American white butterfly
Studying of habitats has exclusively big practical value for fight against the wrecker, especially in the conditions of the Crimea where the territory, as we know, is characterized by a variety of wood vegetation and the crossed land relief, and also for timely detection of the initial centers in areas not populated with the wrecker.
Typical habitats of the American white butterfly in the Crimea, it is wood plants on roadsides iron and especially highways, along channels, in settlements. Wood cultures in lowlands, on flat places are more strongly damaged, than in a residential suburb.
Concentration of the wrecker near structures can be explained by the following reasons:
– dolls in cracks of houses, fences and in other covered places winter better, than in the open district;
– wood plantings near constructions are more rarefied, therefore the best conditions of lighting and optimum temperature for development of the wrecker are created;
– about structures more trees of a mulberry, as plant most preferred by the wrecker grow;
– near structures more often than in other places, transport with which the American white butterfly can be delivered stops;
– attraction of butterflies by light from live rooms.
Alarm system of terms of development of the American white butterfly.
Value of terms of development of the American white butterfly very important for planning and timely carrying out measures of fight on elimination of the wrecker in the conditions of small number. Definition of terms of development of phases of the wrecker has also great value for the areas next to the infected zone, in which it is necessary to establish optimum terms of inspection of plantings in due time to reveal and in the subsequent to liquidate the infection centers.
In the conditions of the Crimea the wrecker prefers the rarefied plantings or separately growing trees, settling in peripheral parts of kroner and branches mainly from South side. A certain part of dolls in February-March leaves a condition winter diapauzy and their further development is strictly connected with temperature which should exceed any certain limit – development "threshold", in the nature it begins when the sum of effective temperatures reaches 130°S.
Ways of distribution.
This wrecker flights extends; average speed of distribution makes 30-40 km a year. Quicker it is settled in the direction of dominating winds. With various cargoes, vehicles in different stages of development of the wrecker can extend on a long distance. Transportation of agricultural production and industrial cargoes are the main way of distribution of the American white butterfly.
Fight methods
The center of the American white butterfly the infected tree or group of trees and the trees next to it and bushes in radius 100m is considered.
For elimination of the centers surely it is necessary to hold agrotechnical events: collecting and destruction of caterpillars and yaytsekladok. Branches with nests of caterpillars cut off and burn. On the damaged trees delete a dead bark, trunks of trees cover with a lime. On personal plots it is necessary to use lovchy belts from a cardboard or a crepe paper. Before an okuklivaniye of caterpillars these belts remove and burn.
Destructive actions provide use entomofagov and biological and chemical preparations. In the center territory all plantings process 2 times with an interval in 10 days. For this purpose use preparations according to the list of pesticides and the agrochemicals resolved for application in Ukraine, the confirmed Ukrgoskomissiyey of Cabinet council of Ukraine. For farms of Karate of 050 EU k.e.-0,2-0,4 l/hectares, Zolon of 35 % k.e. 2,5-3 l/hectares. A consumption of working solution of-2-10 l on 1 tree depending on the size of krone. For a private sector of Karate of 050 EU k.e.-0,2-0,4 l/hectares.
Biological preparations resolved for application in a park zone of Pirineks, 40,8 % k.e. 3,0-3,5 l \hectares, Lipidotsid concentrated, Titr dispute of 100 billion \hectares 2-3 kg \hectares.
I.Trufanova, inspector of the State inspectorate for quarantine of plants of AR Crimea