Use of botanicals extracts to control wild cochineal (Dactylopius opuntiae Cockerell) on cactus pear

An important plague for producer of "nopalitos", cactus pear and forage in Mexico and other countries is D. opuntiae, because it reduces and damages yield rates, and avoids sales and exportation into international market. The aim of this study was to evaluate the effectiveness of vegetal extract for controlling D. opuntiae under laboratory conditions. Twelve vegetal extracts (Chenopodium ambrosioides L., Mentha piperita L, Mentha viridis L., Tagetes erecta L. and Tagetes florida L.) mixed with different emulsifier (Tween 20®, SLS®, CITRIM®, PANODAN®) and commercial insecticide (Agrobion®400) were evaluated; the doses applied were 10% and 3% of botanical extracts and insecticide respectively, diluted in 50 mL of deionized water. Mortality in the stages of nymph I, II and adult females was monitored during 72h and expressed as lethal time (time to kill 90% of wild cochineal). Results showed that the botanical extract in combination with Tween 20® was effective to kill nymph II from 82 to 99%; the effect obtained was dehydration of body and obstruction of spiracles cause insect dead by asphyxia. In nymph I and adult the mortality were 35%, where wax degradation was observed; these results are important for a second application, because it possibly increases the mortality in both stages