**2.9 Spray toxicity bioassay**

The insecticidal activity of crude OMW and the two commercial insecticides (used as positive controls, Cordus and Kemaban 48 EC) to control *P. opaca* larvae was assessed by a spray toxicity bioassay conducted using 5 g of palm compost in

plastic boxes. Cordus and Kemaban are composed of 50 and 48% chlorpyrifos-ethyl, respectively. Chlorpyrifos is an insecticide, acaricide and organophosphate miticide used mainly against insect pests. Concentrations of 0.5 and 1 μL/mL of Cordus and Kemaban were dissolved in distilled water. Many preliminary tests have been performed to select the doses to be used for positive controls. For each solution and crude OMW, a volume of 5 mL was sprayed on the surface of the palm compost every 24 hours for 6 days. Based on dry matter, the dose of OMW was calculated to be 94.86 g/L (≈95 mg/mL) (**Table 2**). The cumulative dosage of OMW polyphenols applied over a six days treatment was calculated. For each treatment, six larvae were placed in each box using ten replicates. Weight loss and mortality of positive controls and OMW were recorded 8 hours per day every 2 hours. Negative control was treated with distilled water. The larva was considered dead, when no movement was recorded when shaking. Observations were made on all treated larvae until their death.
