Bioactivity and biochemical efficacy of chitinase and Justicia brandegeana extract against Red Palm Weevil Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae)

The red palm weevil Rhynchophorus ferrugineus is a large polyphagous insect, and this study was carried out to isolate chitinase from Beauveria bassiana as well as phytochemical screening of Justicia brandegeana to elucidate its effect as biocontrol agents against the red palm weevil and its possible effect on enzymatic bioactivity. It is the first time that the lipoid constituents of J. brandegeana were examined by both gas–liquid chromatography (GLC) and gas chromatography–mass spectrometry (GC/Mass). The results showed that the highest rates of mortality in treated prepupae were 35.0% and 30.0% with the higher concentration of chitinase (25 ppm) and petroleum ether extract of J. brandegeana (1,200 ppm), respectively. Moreover, changes in enzyme activity of ALP, PO, GPT, and GOT in the prepupal stage after treatment with LC(50) chitinase and J. brandegeana extract were 36.63 & 14.32, −21.99 & 41.20, −11.02 & 47.05, and −36.00 & 21.43% compared with untreated control, respectively. This study demonstrated effectiveness of chitinase, and the petroleum ether extract of J. brandegeana has potent effect against Rh. ferrugineus due to its disturbance effect on the enzymatic system, protein as well as DNA damage.