Bionomics and behaviour of mango leaf webber, Orthaga euadrusalis Walker.
Patel D. B., Korat D. M., Borad P. K.
Author Affiliation: Department of Agricultural Entomology, B.A. College of Agriculture, Anand Agricultural University, Anand - 388 110, Gujarat, India.
Karnataka Journal of Agricultural Sciences 20 : 644-647
Abstract : The development and behaviour of O. euadrusalis on mango were studied under laboratory and field conditions in Anand, Gujarat, India. The female moths laid greenish, oval and flattened eggs singly or in clusters, usually on the lower surface of the leaf near the midrib or vein. The female moth sometimes laid eggs on the upper surface of the leaf and tender twigs. The incubation period required 4.29 days. The egg hatching percentage was 93.03%. The larvae fed gregariously on tender leaves, scraping the leaf surface. At the early stages, the larvae webbed 2 or 3 leaves together and fed on them by cutting the leaves from the edges towards the midrib, leaving behind the network of veins. During the late stages, the larvae were found feeding voraciously and webbing the shoots and leaves together. The leaves loosened from their stalks, often detached, but remained entangled in webs in trees. Numerous dried bunches of shoots and leaves were visible from a distance on severely attacked trees. The duration of the 1st, 2nd, 3rd, 4th, 5th, 6th and 7th instar larvae was 4.16, 4.68, 3.48, 3.58, 3.86, 4.18 and 5.76 days, respectively. The total larval duration was 29.70 days. The pre-pupae were pale greenish to dark black. The pre-pupal period lasted 3.84 days. Pupation occurred within the web, inside the silken cocoon. The lifespan of the male and female pupae was 15.80 and 17.16 days, respectively. The male adults lasted 4.00 days, whereas the female adults lasted 8.30 days. The pre-oviposition, oviposition and post-oviposition period required 3.30, 3.70 and 1.30 days, respectively. Each female laid an average of 63.00 eggs. The sex ratio (male:female) was 1:1.18 under field conditions and 1:1.14 under laboratory conditions. The total lifespan of the male and female adults was 56.60 and 59.60 days, respectively.