Ecofreindly Management of Ash Weevil, Myllocerus viridanus Fabr. (Coleoptera: Curculionidae) in Moringa concanensis Nimmo Seedlings Raised from Diverse Seed Sources

Abstract

A reconnaissance survey was conducted in Barmer, Pali, Churu and Jodhpur District of Rajasthan to document the occurrence of the Konkan Moringa, Moringa concanensis Nimmo and collection of seeds for multiplication as this tree is categorised under threatened species in Rajasthan. Seeds were collected from the marked trees and raised seedlings in poly house with an overall germination of 62%. Physical parameters of pods like pod length, pod width, seeds per pod were also recorded. Findings revealed that average pod length varied from 10.3-24.0 cm with an average of 17.3 cm. Pod width varied from 0.9-2.6 cm with an average of 1.63 cm. Number of seeds per pod varied from 5.0-14.0 with an average of 8.9. Seedlings of approximately 45-60 days old exhibited notable infestation by the Ash weevil Myllocerus viridanus Fabr. (Coleoptera: Curculionidae), a defoliating pest was recorded. The occurrence of this Ash weevil M. viridanus Fabr. on M. concanensis reported here represents a new host association not previously described in the literature. The adult of Ash weevils caused characteristic marginal and interveinal notching on tender leaves, whereas larvae fed on fine roots, leading to stunted growth and poor plant vigour. Preliminary damage assessment revealed significant leaf loss in infested plants. All seedlings examined exhibited the presence of the pest, resulting in a 100% infestation incidence across the population. The mean number of damaged leaves per seedling was approximately 25.29, corresponding to percent infested leaves of 77.6% relative to total foliage, indicating that more than three-fourths of the foliage was affected. This high proportion of damage showed that plants were in severe infestation pressure, with the majority of seedlings experiencing substantial defoliation. An eco-friendly management approach using neem oil was evaluated and application at 1% concentration proved highly effective in significantly reducing foliar damage.