Preparation and evaluation of biocontrol agent: its impact on growth of golden apple snail, Pomacea Canaliculata

Golden apple snail or scientifically known as Pomacea canaliculata is a worst threat to paddy farming in most of the country including Malaysia. The novelty of this research is production of green biopesticide based on microbial by-products against P. canaliculata. To achieve this, microorganism was isolated, screened, characterized and molecularly identified. Based on this experiment, two isolated fungi known as T. stipitatus and A. awamori was used. The toxicity of the fungi filtrates was studied by analyzing the mortality of the snails with results of LC50 for A. awamori is 45% and 47% while the LC50 for T. stipitatus is 49% and 54% for non-autoclaved and autoclaved filtrates respectively. In pathogenicity test, A. awamori is specifically pathogenic to P. canaliculata where at 3.85 x 108 spores/mL, about 37% snail’s mortality recorded compared to no dead snails at 3.8 x 108 spores/mL of T. stipitatus. The protein, protease, glucose, alkaline phosphatase, catalase and glutathione changes inside the snail’s body was evaluated. Protein level in normal snail is 2.24 mg/mL but changes to 1.46 mg/mL and 2.40 mg/mL when exposed to non-autoclaved and autoclaved A. awamori filtrates. Larger increased observed in the alkaline phosphatase activity from 0.01 units/mL in control snails to 0.11 units/mL and 0.14 units/ml when exposed to non-autoclaved and autoclaved filtrates. Increased in the filtrates concentration brings an increase in energy demand for detoxification of the filtrates. Higher demand for energy consumption cause increase in protein, protease activity, alkaline phosphatase activity and glucose. Toxic stresses cause by the filtrates stimulates increased production of hydrogen peroxide, where catalase activity elevated to convert them into water and oxygen in order to maintain the balance inside the body. This stress also caused changes in the snail’s behavior. Normal snail shows active movement of foot, tentacles and response against stimuli. However, when exposed to filtrates, the snails become inactive. Survival analysis shows the efficiency of A. awamori filtrates suppress the snails survival with no survival was observed after three weeks of exposure even at lowest sub-lethal concentration. The compound that responsible as molluscicidal agent was analyzed using HPLC and LC MS/MS showing the presence of erythritol and piperazine, both are active agent in insecticide.