Physical characteristics of insecticide spraying liquids with mineral oil and droplets formed on citrus leaves
Jaqueline Franciosi Della Vechia, Renata Thaysa da Silva Santos, Daniel Junior de Andrade & Marcelo da Costa Ferreira
The physical characteristics of a spray liquid are important in getting a good droplet formation and efficiency control over a target pest. These characteristics can be changed in various ways, the addition of mineral oil can be one of them. Thus, the aim of this study was to evaluate the physical characteristics of the surface tension of the diflubenzuron insecticide using different mineral oils in two concentrations and the interaction of droplets produced on the leaf surface of orange through the formed contact angle. Therefore, seven spraying liquids were prepared composed of diflubenzuron, often used in citrus for insect pest control, and three mineral oils (Argenfrut, OPPA and Nimbus) in two concentrations (0.25 e 0.5% v/v). Pendant droplets formed from these mixtures were measured to examine their impact on surface tension. Droplets were applied to the surface of orange leaves and the contact angle formed were measured. The addiction of the mineral oil to diflubenzuron reduce the surface tension and contact angles of droplets on leaf surfaces, resulting in a large surface area covered. Among the evaluated mineral oils, OPPA and Nimbus showed greater reduction in surface tension and smaller droplets contact angles on the orange leaf. Therefore, the application of the diflubenzuron with OPPA or Nimbus, at concentrations of 0.25 and 0.50%, provide a better spreadability of the sprayed droplets.