Pesticidal activity of Cratyllia mollis seed lectin preparation (cramoll 1,2,3) against the termite Nasutitermes corniger and mite Tetranychus bastosi

Abstract

There is a need to control populations of the termite Nasutitermes corniger and the mite Tetranychus bastosi since they act as urban and agricultural pests. Plant lectins (carbohydrate-binding proteins) have been suggested as a strategy for pest control. Thus, this study investigated the termiticidal and acaricidal activities of a mixture containing three Cratylia mollis seed lectins (Cramoll 1,2,3). Assays were performed to evaluate the effects of Cramoll 1,2,3 on the survival, behavior, and digestive enzyme activities of N. corniger. In T. bastosi assays, the effects on survival and egg hatching rates were determined. Cramoll 1,2,3 increased N. corniger mortality (LC50 of 0.078 and 0.199 mg mL−1 for workers and soldiers, respectively). The Cramoll 1,2,3 preparation was not resistant to hydrolysis by termite gut enzymes. However, the sample containing the released peptides was able to slightly increase exoglucanase and endoglucanase activities (both by 8%) and inhibited amylase, xylanase, and trypsin-like activities by 14%, 11%, and 56.7%, respectively. Cramoll 1,2,3 was toxic to T. bastosi adult females with an LC50 of 0.14 mg mL−1 and showed ovicidal activity (EC50 of 0.16 mg mL−1). Cramoll 1,2,3 also decreased the acari population growth rate. In conclusion, Cramoll 1,2,3 proved to be a pesticide against insect and acari pests and was the first lectin preparation with acaricidal potential against T. bastosi.