Effect of Rosmarinus officinalis, leaf methanolic extract on crustacean cardioactive peptide, digestive enzyme activities and nutritional indices of Helicoverpa armigera (Lepidoptera: Noctuidae)

Efficacy of methanolic leaf extract of Rosmarinus officinalis on third instar larvae of cotton bollworm, Helicoverpa armigera (Hübner) was studied. The value of LC50 and LC20 were 5138 and 12347 ppm, respectively.  One hundred microliters of the Rosemary’s mehanolic extract at 5138 ppm was added to 0.9 gr artificial diet. Efficiency of digested food (ECD), efficiency of conversion of ingested food (ECI), relative consumption rate (RCR) and relative growth rate (RGR) were decreased after 72 h but approximate digestibility (AD) was increased. It also decreased α-amylase, protease and lipase activity in the midgut of third instar larvae of H. armigera. Incubation of dissected midgut with crustacean cardioactive peptide (CCAP) increased lipase activity. Feeding on artificial diet containing plant extract caused decreasing in CCAP level in the brain, hemolymph and midgut of the insect. The results showed feeding on diet containing rosemary’s extract inhibits release of CCAP in the midgut and brain that itself leads to reduction of α-amylase, lipase and protease activities.