Towards a development of novel bioinsecticides for organic control of Planococcus ficus in vineyards

The mealybug species, Planococcus ficus Signoret (Hemiptera: Pseudococcidae) is a pest that mainly affects grapevine plantations (Vitis vinifera L.), causing huge economic losses in the world. The numerous problems caused by the use of synthetic pesticides on the environment and human health have motivated the development and implementation of natural pesticides. The objective of this work was to develop effective and efficient contact bioinsecticide formulations for the control of P. ficus in vineyards. Anti-mealybug formulations were developed using (R)-(+)-pulegone as an active principle, TWEEN® 20 and soy lecithin powder as surfactants, and limonene and diatomaceous earth (DE) as insect waxy layer reducers. The insecticidal properties of formulations against vine mealybugs and their grapevine leaf phytotoxicity were evaluated in laboratory conditions. Pulegone+DE+Lecithin and Pulegone+Limonene+DE+Lecithin formulations showed the highest mortality rates of P. ficus (more than 70 % mortality) at 24 h and 48 h of treatment. This high mortality is probably due to an interaction between pulegone, DE and soy lecithin that allows more molecular mobility and increases the efficiency of the active substance, making it enter and act on the insect. In conclusion, the Pulegone+DE+Lecithin and Pulegone+Limonene+DE+Lecithin formulations can be an efficient tool for the organic control of P. ficus in vineyards.