HYPHANTRIA CUNEA PDF

It is one of the few insect pests introduced from North America into other continents. Introduced to what was formerly Yugoslavia in the s firstly recorded in [2] , it now has occupied probably its entire range in Europe from France to the Caspian Sea in the east as well as penetrated into Central Asia : Turkmenistan from to , Uzbekistan Fergana valley from to , Kyrgyzstan , and southeastern Kazakhstan. It was also introduced into Japan in and has adjusted its number of generations per year since its arrival. The fall webworm originated in North America but spread very quickly across the world due to factors such as trade and rapid transit.

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The sex ratio is usually , females living for days and males for days less. Adults emerge in the evening and rest initially on branches, twigs and leaves before flying to preferred food plants. They are able to fly several kilometres. Females each lay eggs, mostly during days, on the lower surface of the leaves on the upper and outer parts of trees; even heavy rain does not dislodge the eggs.

There are two generations annually and occasionally a partial third. Mulberry is the most favourable host for female fecundity and larval development; however, most larval nests of the first generation are found on Acer negundo, and those of the second generation on fruit trees. In Romania, it was demonstrated that, although H. In Hungary, there are two generations per year and the larvae pass through seven instars.

Once accumulated temperatures above this level exceed degree days, larvae hatch and accurate forecasts can be made to within days. In Russia, hatching of eggs occurs mainly during the morning between the hours and evening Fedosov, Others overwinter in the soil to a depth of 10 cm. In Korea, adults generally emerge between the hours of and , the peak being Copulation occurs only once a day, for a few minutes, before sunrise. Eggs are laid in groups of about ten. Larvae can withstand up to 15 days starvation, although the resultant reproductive capacity of the adult will be adversely affected.

In Nova Scotia Canada , females lay about eggs, all in one mass, on leaves of deciduous trees and shrubs. Larvae construct a colonial web and feed together within it. Diapause is facultative and depends on climate. On average, males live for about 8 days. In Alabama USA , there are two generations per year, one generation in spring and one in the late summer, and the species passes through 11 larval instars Williams et al. For more information, see Chalcote and Gentry , Yaroshenko , Boehm International trade can facilitate movement to new areas.

The facility of the larvae to withstand starvation for up to 2 weeks means that they can easily be transported on vehicles to different areas and survive to initiate new infestations. Mass migrations due to exhausted food plants or the search for new sites often end in urban areas where the pest invades wood piles, houses, roads and vehicles which can transport it to new and uninfested areas Giovanni et al.

Transportation of H. There is a certain risk of entry as eggs and larvae imported by amateur entomologists. Notes on Natural Enemies Top of page H. Introductions of a number of the more important parasitoids from North America were attempted and continued into the s.

However, none of them are known to have become established Greathead, ; Clausen, , and subsequent biological control attemps have focused on the the use of Bacillus thuringiensis sprays. Impact Top of page In Europe, where H. In eastern Europe, mulberry and the widely planted amenity tree Acer negundo are seen to be particularly attacked. Experiments showed that sixth-instar larvae of H. Their colonial habit nests of silk enclosing the leaves is particularly damaging to individual trees.

On its home territory in USA, it is conspicuous, mainly on wild trees, but seldom of economic importance Johnson and Lyon, Detection and Inspection Top of page The sex pheromone obtained from female H. It is not likely to be confused with other Lepidoptera. Prevention and Control Top of page Due to the variable regulations around de registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control.

Chemical Control Both mechanical destroying nests and chemical means are used for control. In Russia, diflubenzuron gave adequate control of H. However, chemical control with insecticides is not without problems. In Italy, where mulberry is the preferred host of H. Biological Control There has been much research on biological control.

The most used and researched antagonistic organisms are subspecies of Bacillus thuringiensis. Preparations of B. Other pathogenic organisms are the fungi Beauveria bassiana Jasinka, and B.

Entomophagous nematodes Steinernema feltiae can be also used to reduce H.

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Fall Webworm (Hyphantria cunea)

Adults are pale white in most cases but can have thousands of different phenotypes, as they appear to have variable black pigmented spots. The degree of pigmentation varies a lot per individual and may range from a few hardly noticable dots to heavy black spots to adults that appear to be almost completely black. The adults have no functional mouthparts and do not feed, and only live for about a week. After hatching from their cocoons, the males seek a female and pair. After pairing the females disperse and lay up to a few hundred pale, translucent green eggs upon a rough surface usually a leaf or twig, but it can be random. Eggs hatch quickly in two to three weeks time, depending on the temperature.

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EPPO Global Database

Distribution Back to Top The fall webworm originally occurred throughout North America to its northernmost limit in southern Canada. The fall webworm was introduced into Yugoslavia in the s, and since then has invaded most of Europe. It now also inhabits parts of China and North Korea, again due to accidental introduction, and it is found in Japan. Figure 2. Worldwide distribution as of

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Hyphantria cunea — “Fall webworm”

The sex ratio is usually , females living for days and males for days less. Adults emerge in the evening and rest initially on branches, twigs and leaves before flying to preferred food plants. They are able to fly several kilometres. Females each lay eggs, mostly during days, on the lower surface of the leaves on the upper and outer parts of trees; even heavy rain does not dislodge the eggs.

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Fall webworm

Species - cunea Diet Fall webworm caterpillars will feed on any one of over tree and shrub species. Preferred host plants include hickory, pecan, walnut, elm, alder, willow, mulberry, oak, sweetgum, and poplar. Life Cycle The number of generations per year depends greatly on latitude. Southern populations may complete four generations in one year, while in the north the fall webworm completes only one life cycle. Like other moths, the fall webworm undergoes complete metamorphosis, with four stages: Egg — The female moth deposits several hundred eggs on the undersides of leaves in spring. She covers the mass of eggs with hairs from her abdomen.

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