Insecticidal Potential of Eco-friendly Entomopathogenic fungi as Myco-insecticide for the management of fall armyworm (Spodoptera frugiperda) under In-vitro condition
The invasive polyphagous pest fall armyworm Spodoptera frugiperda, (Lepidoptera: Noctuidae) is a migratory pest of maize in Asia and other countries including Pakistan. It mostly feed on leaves at larval stage and this pest can be controlled by various management strategies including chemical control but the pest has now developed resistance against major insecticides. However, this pest can be controlled through other strategies including physical, biological, mechanical especially eco-friendly entomopathogenic fungus Beauveria bassiana, Trichoderma verdii and Metarhizium anisopliae other than chemical control methods. Through this ecosystem and nature can be protected from hazardous effects of chemicals. Trials conducted in-vitro reveals that bioassay of entomopathogenic fungi like Beauveria bassiana Trichoderma and Metarhizium anisopliae can effectively control FAW under control condition, and it was found that Metarhizium anisopliae is very effective against every instar of FAW i.e. 1st ,2nd ,3rd and 4th However, mortality percentage was recorded 85.5% on 1st 2nd and 3rd instar respectively at 40ppm dose and was recorded minimum 18.6% on 10ppm dose of Trichoderma during bioassay under control condition.During second instar larvae of bioassay entomopathogenic fungi Metarhizium anisopliae was recorded very effective and showed mortality up to 83.3% at dose 40ppm after exposure of three days at 25°C approximately. While minimum mortality of FAW was recorded at 10 ppm after exposure of three days under same controlled conditions. On release of 2nd instar larvae Metarhizium anisopliae was found with more entomopathogenic potential and caused highest mortality and on the other hand minimum mortality was recorded i.e. 48% on 10ppm dose exposer of M. anisopliae after three days at 25°C , and 53% humidity. The studies showed that entomopathogenic potential of fungi decrease with shifting of larval instars from 1st towards last. At 3rd and 4th instar larvae only M. anisopliae was recorded effective and was found to control the larvae population up to 78.5% at 40ppm and 55.8% mortality was observed on 4th instar respectively after exposer of three days. Among all Metarhizium anisopliae was found with more insecticidal properties as compare to Beauveria bassiana and Trichoderma.This comparative study shows that M. anisopliae was found with broad spectrumhighest insecticidal properties as compare to Beauveria bassiana and Trichoderma. at multiple larval stages under control condition. This M. anisopliae have also the exophytic sporulation characters and dynamic insecticidal potentials while Beauveria bassiana and Trichoderma was recorded with endosporulation characters.