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Hyphantria cunea (Fall webworm)

 

Description

Eggs: Yellowish, and are laid as cluster . Larvae: Brownish-grey, attains 40 mm when fully developed, and has 12 small warts surmounted by characteristic tufts of hair. Pupa :Bears 12 characteristic appendages at the posterior end. Adult :Moth with a wingspan of 25-30 mm; forewings are white or have black spots arranged in a number of rows; hindwings are also white with a small black spot on the leading part.

Biology and Damage

H. cunea attacks a wide range of forest and fruit trees. More than 250 species of host plant have been recorded. The most favourable plants for development are mulberries, Acer negundo and A. platanoides, apples, pears, cherries (Prunus cerasus and P. avium), and plums. H. cunea larvae are rapid defoliators of forest and fruit tree species.

After 1980s, it become a serious hazelnut pest in Turkish hazelnut orchards, especially in provinces of mid blacksea area of Turkey. Adult emergence from overwintered pupae began in late May, and continue about 4 weeks in that area. Summer generation adults appear from late July to mid- August. Larvae can be seen from late May to late October in hazelnut orchards. Almost once in a every four year it makes plug and consume all leaves on hazelnut trees during September and October. There are 2 generation per year. Larvae are black headed type.It is hard to rear the larvae on hazelnut leaves in laboratory conditions on the contrary to hazelnut leaves in orchards.

The sex ratio was usually 1:1, females living for 4-8 days and males for 1-2 days less. They were able to fly several kilometres. H. cunea is sensitive to moisture and, at 50-60% RH and 25°C, laid fewer eggs and adults died prematurely (RH of 70-80% and temperatures not exceeding 22-25°C are most favourable). Females each laid 293-1892 eggs, mostly during 1-2 days, on the lower surface of the leaves on the upper and outer parts of trees; even heavy rain did not dislodge the eggs. Mulberry was the most favourable host for female fecundity and larval development; however, most larval nests of the first generation were found on Acer negundo, and those of the second generation on fruit trees. Pupae are cold-resistant if well hidden in bark, where 82-84% of them hibernate. Others overwinter in the soil to a depth of 10 cm.(EPPO).

Common Names

USA: Fall webworm, American white moth;TR: Amerikan Beyaz Kelebeði ; FR: Ecaille fileuse; DE: Amerikanischer weisser Barenspinner;SPANISH: Gusano de la bolsa; ITALIAN: Falena tessitrice.