| The present study highlights the practical application of a Piper-based botanical insecticide for controlling insect pests of the home and garden in urban areas in eastern Canada and northeastern North America. Biopesticides, including botanicals, can offer a safe and effective alternative to conventional insecticides for controlling major insect pests within an IPM program. Secondary compounds from the Piperaceae family, specifically the abundant isobutyl amides and lignans, have shown promise for insecticidal applications.; A method for extraction and HPLC-MS analysis of Piper spp. was developed in order to allow quick and accurate measure of piperamide levels in P. nigrum, P. tuberculatum, West African Guinea pepper, P. guineense Schum and Thonn, and in less recognized species from Central America. Extraction of leaf and peppercorn material with 50:50 ethyl acetate and water provided a greater than 80% recovery of spiked piperine. HPLC analysis using a binary gradient of acetonitrile and water provided a clean separation of the major amide peaks between 5 and 12 min. The use of APCI-MS improved the detection limit 10 fold below the 2-ng limit of the HPLC-DAD method.; Extracts from P. nigrum, P. guineense and P. tuberculatum were tested for efficacy against insects from five orders. Among the insect pests tested, the most sensitive species were, in order of increasing lethal concentration: Eastern tent caterpillar, Malacosoma americanum F. < European pine sawfly larvae, Neodiprion sertifer Geoffroy < spindle ermine moth larvae, Yponomeuta cagnagella Hubner < Viburnum leaf beetle larvae, Pyrrhalta viburni Paykull < stripped cucumber beetle adult, Acalymma vittatum Fabrcius < Colorado potato beetle adult, Leptinotarsa decemlineata (Say) < Japanese beetle adult, Popillia japonica Newman < hairy chinch bug, Blissus leucopterus hirtus Montandon. Greenhouse trials revealed that the pepper formulations also had a repellent activity thus protecting plant leaves from: (1) herbivory by lily leaf beetles, Lilioceris lilii (Scopoli) adults and larvae, and striped cucumber beetle, Acalymma vittatum F. adults and (2) oviposition by European corn borer, Ostrina nubilalis (Hubner).; When an insecticide resistant strain of potato beetle larvae was tested with the P. tuberculatum extract, there was less than a two fold tolerance ratio compared to the 22-fold tolerance ratio to cypermethrin, a pyrethroid. An in vitro polysubstrate monoxygenase (PSMO) enzyme assay, using the substrate methoxyresorufin O-demethylation (MROD), determined that piperine, is responsible for inhibition of that specific enzyme. A subsequent toxicokinetic study determined that piperine is quickly eliminated from the exoskeleton (t1/2 = 16.5 h) and hemolymph (t 1/2 = 12 h) of the adult American cockroach Periplaneta americana L. after a topical application. (Abstract shortened by UMI.)... |
