Effectiveness of botanical extracts from ten plants on mortality and larval repellency of Rhynchophorus palmarum L., an insect pest of the peach palm Bactris gasipaes kunth in amazonian peru

Pest resistance to chemical insecticides has grown in recent years, which is the motive for the search for alternative methods, such as plants with larvicidal activity. The objective of this research was to evaluate mortality and larval repellency of Rhynchophorus palmarum L. (Curculionidae), a pest of the Peach palm Bactris gasipaes Kunth to ten plants with biocide potential: india heliotrope (Heliotropium indicum L., Boraginaceae), angels' trumpets (Brugmansia sp., Solanaceae), wandering jew (Tradescantia zebrina Hort. ex Bosse, Commelinaceae), nettles-purge (Jathropa curcas L., Euphorbiaceae), soapberry (Paullinia clavigera Schltdl., Sapindaceae), red spurge (Euphorbia cotinifolia L., Euphorbiaceae), annato (Bixa orellana, Bixaceae), golden shower (Cassia fistula L., Fabaceae), birthwort fruit (Aristolochia pilosa Kunth, Aristolochiaceae) and pareira (Chondrodendron tomentosum Ruiz & Pavon, Menispermaceae). Bioassays with R. palmarum were performed at 1, 4, 8, 12 and 24 h exposure, employing 660 larvae under laboratory conditions and aqueous botanical extracts of the plants at a 1:3 (w/v) ratio. At 24 h exposure, the highest mortality percentage of R. palmarum was observed with birthwort fruit (73.30%: liquefied leaves and stems), wandering jew (70%: liquefied leaves and stems) and pareira (60%: wood and bark in decoction). In the case of repellency, the highest effects were found in birthwort fruit (80%), pareira (73.30%) and wandering jew (71.70%). In addition, nettles-purge (liquefied seeds) produced only 3.3% mortality but significantly 55% repellency. The possibility of employing these botanical extracts in integrated management of R. palmarum is analyzed.