Studies on mango leaf webber, Orthaga spp. with special reference to study the biology of leaf webber, Orthaga spp.
Author(s): Archana Kerketta, Dr. Sanjay Sharma, Dr. RKS Tomarn and Dr. BP Katlam
Abstract: “Studies on mango leaf webber, Orthaga spp. with special reference to seasonal incidence, biology and management” was conducted during the year 2015-16 and 2016-17at the Horticultural orchard of BTC College of Agriculture and Research Station, Bilaspur (C.G). Data on seasonal incidence indicated that minimum larval population of 21.24 larvae/tree was recorded on Himsagar followed by Kurkan, Kesar, Karela, Sunderja, Dilpasand, Dashari, Langra and Alphanzo with 21.83, 23.21, 24.02, 29.43, 30.28, 31.08, 32.19 and 33.16 larvae/tree, respectively. The minimum webbing 12.50 webs/tree was recorded on Himsagar followed by Kurkan, Kesar, Karela, Sunderja, Dilpasand, Dashari, Langra and Alphanzo with 16.38, 17.39, 17.89, 18.13, 19.52, 19.84, 20.10 and 21.80 webs/tree, respectively. Biological study of leaf webber, Orthaga exvinacea Hampson revealed that female moths lay greenish dull, oval, flattened eggs singly or in groups on the lower surface of leaves near the midrib or vein. The width and length of the eggs were 0.97 and 0.67 mm, respectively. The incubation period was 4.80 days and the hatching rate of eggs was 89.60 percent. The larvae passed through seven instars, the first, second, third, fourth, fifth, sixth, and seventh instar larvae takes for 4.40, 5.20, 3.60, 4.00, 5.00, 5.80, and 3.00 days, respectively. The average larval period was 31.00 day and Pre-pupae period registered for 5.20 day. The pupation occurs inside the web, within the silken cocoon and pupal periods lasts for 18.60 day. Leaf webber adults are brownish grey forewings with wavy lines, male and female life spans completes in 4.40 and 8.40 days, respectively. The pre-oviposition, ovoposition, and post-oviposition periods were recorded as 3.40, 4.60, and 1.60 days respectively and the average fecundity of female was 84.60 eggs. Under laboratory conditions, the male to female ratio was 1: 1.20. and total life cycle completed within 59.20 and 63.20 days, respectively.
