Investigation on Spraying Percentage of Droplets at Leaves and Ears using Several Pesticide Spraying Methods in Several Growth Stages of Maize (<i>Zea mays</i> L.)

<p>To clarify a basic knowledge on pesticide application methods against fall armyworm (Spodoptera frugiperda), we investigated the spraying percentage of droplets on leaves and ears covered by water-sensitive paper using several pesticide-spraying methods, including tractor-mounted boom sprayers, handheld electrostatic sprayer, and drone-spraying at various growth stages of maize (Zea mays). In boom spraying methods, the spraying percentages of droplets under the sprayed rate of 200 L per 10 a at the 1st-2nd leaf stage was over than 98％. In the case of 100 L per 10 a at the 5-6th leaf stage, they were less than 50％. For the tractor-mounted boom sprayer, spraying percentages of droplets at the top- and middle-leaves in the 9-10th leaves stage were lower than those at the lower-leaves. On the other hand, the electrostatic sprayer exhibited the opposite results. In drone-spraying at the dough-ripe maize, they were obtained more than 60％ in base and middle part of upper- and middle-leaves under the amount of 100 L per 10 a. These results elucidate important information that contributes to our basic knowledge on the selection of pesticide application methods against fall armyworm. It will be necessary to clarify the relationship between the spraying percentage of droplets and the control/exterminating effect.</p>