Nematicidal and Insecticidal Activity of Proteases from Carica papaya and Ananas comosus

Plant proteases are well known for their various industrial applications. Papain, present in papaya latex ( Carica papaya ) and pineapple bromelain ( Ananas comosus ), is undoubtedly the most studied and widely used vegetable protease in the food and pharmaceutical industry worldwide. However, its potential as a biopesticide has been little explored. The objective of this study was to evaluate the activity of proteases from Carica papaya latex and peel and crown of Ananas comosus fruits on agricultural pests. To evaluate proteolytic activity on nematodes, extracts, and approximately 50 juveniles of Panagrellus sp. were placed in microtubes. To evaluate the insecticidal effect, larvae and pupae of Tenebrio molitor L. were submerged in active and denatured extracts. Additionally, larvae of T. molitor were fed an artificial diet at doses of 0, 100, 250, and 500 mg/g of wheat bran. The weight and number of dead larvae were recorded, and feeding behavior was evaluated. The proteases of papaya latex and papain caused reduction ( p < 0.05) on Panagrellus sp. The extracts showed a toxic effect ( p < 0.05) against the larvae of T. molitor . Active papain resulted in the absence of wings in 53.3% of adults from the pupae, and no malformation caused by denatured papain was observed. No mortality was observed in larvae fed an artificial diet. However, there was a strong feed reduction, reduction in the relative rate of consumption, reduction in growth and feed conversion efficiency caused by papaya latex. The results of this study show that plant proteases have the potential for the development of sustainable alternatives for the control of arthropod pests and parasitic nematodes.