Biology, population dynamics and bio-intensive management of fruit borer, Conopomorpha sinensis Bradley in litchi
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Date
2024
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Punjab Agricultural University
Abstract
The present study entitled “Biology, Population Dynamics and Bio-Intensive Management of Fruit Borer, Conopomorpha sinensis Bradley in Litchi”, was conducted at different locations in Punjab, New Delhi and Karnataka during 2020-2023. Laboratory rearing procedures for C. sinensis were standardized during 2021-2022. Studies on oviposition preference revealed that the C. sinensis females laid the highest number of eggs (74.5±1.74) on litchi fruits. Each female moth laid on an average 82.2 ±1.87 eggs/reproductive cycle. Under laboratory conditions, C. sinensis completed its life cycle in 32.5±0.97 days, while under field conditions, it was completed in 30.8 ± 0.7 days. The morphological characterization confirmed that the fruit borer species responsible for litchi fruit damage in Punjab is C. sinensis. The molecular characterization studies conducted on specimens of Conopomorpha spp. collected from 19 locations from 10 litchi growing states of India, served as conclusive evidence that C. sinensis is the only fruit borer species belonging to the genus Conopomorpha responsible for causing substantial damage to litchi fruits in India. The present study indicated that both pupae and adults of C. sinensis showed remarkable sexual dimorphism. Population dynamics studies showed that the Calcuttia cultivar was more susceptible to fruit damage as well as to pupation by C. sinensis as compared to Dehradun and Seedless Late cultivars. Maximum and minimum temperatures favoured larval incidence. High humidity and rainfall have a significant positive impact on C. sinensis pupae. The egg-parasitoid Trichogramma embryophagum (Hartig), when released in litchi orchards @ 4,000 eggs/tree resulted in the lowest per cent fruit infestation (16.7±0.9 %) with a significant per cent reduction in fruit damage (57.9 %) over control. PAU Homemade Neem Formulation @ 18 ml/L followed by PAU Homemade Dhrek Formulation at the same concentration resulted in lowest per cent fruit infestation compared to control. Based on the most effective treatments from various experiments conducted during 2021, involving the best dose of biocontrol agent and PAU homemade botanical formulations, a Bio-intensive Pest Management (BIPM) module for eco-friendly management of C. sinensis was evaluated at 4 locations in 3 litchi growing districts of Punjab and was successfully developed. Module 4 resulted in the lowest per cent fruit infestation of 6.5±0.23% with 80.6 % reduction in fruit damage over control and also provided the highest yield of 6.45 MT/acre with an average yield of 85.5±2.04 kg/tree, with a notable increase in yield of over 2.33 metric tons/acre. This increase in yield, when converted into net income over control (Rs. 3, 29,173. 40), resulted in the most economical modules among all the modules tested. The best module comprising management practices like clean cultivation by removal of plant debris in the orchard; collection and destruction of infested litchi fruits; 3 releases of T. embryophagum @ 4000 eggs/tree at 7 days intervals starting from fruit formation stage; 2 sprays of PAU Homemade Neem Formulation @ 18 ml/L followed by 1 spray of PAU Homemade Dhrek Formulation @ 18 ml/L and panicle bagging with propylene non-woven pink bags starting from two weeks after fruit set, was identified as the most successful module in combatting C. sinensis. Furthermore, a slow-release pheromone trap was developed against C. sinensis using Gas Chromatography-Mass Spectrometry (GC-MS).The male attractant was found to contain components such as 9-Tetradecenal, 9-Tetradecen-1-ol acetate, cis-9-Hexadecenal, Z, E-7, 11-Hexadecadien-1-yl acetate, and E-2-Octadecadecen-1-ol while the female attractant consisted of 9, 12-octadecadienoic acid, heneicosyl-cyclohexane, 3-methyl-2-(3-methylpentyl)-3-buten-1-ol and 2-heptyne-4-one. The results indicated that the highest number of female moths (27.4±0.60) were trapped on Del Ta Insect trap loaded with the male attractant during the first week after installation.
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Masrat Siraj (2024). Biology, population dynamics and bio-intensive management of fruit borer, Conopomorpha sinensis Bradley in litchi (Unpublished Ph.D. Dissertation). Punjab Agricultural University, Ludhiana, Punjab, India.