Control Efficacy and Deposition Characteristics of an Unmanned Aerial Spray System Low-Volume Application on Corn Fall Armyworm Spodoptera frugiperda

Abstract

As a major global pest, fall armyworm (FAW), Spodoptera frugiperda, invaded China in 2019, which has seriously threatened the safety of China's food production and raised widespread concerns. As a new low-volume application technology, an unmanned aerial spray system (UASS) is playing an important role in the control of FAW in China. However, the studies on the effect of the water application volume on the efficacy of FAW using UASS have been limited. In this study, Kromekote® cards were used to sample the deposition. The method of using a sampling pole and sampling leaf for the determination of deposition. Four water application volumes (7.5, 15.0, 22.5, and 30.0 L/ha) were evaluated with regard to the corn FAW control efficacy. A blank control was used as a comparison. The control efficacy was assessed at 1, 3, 7, and 14 days after treatment (DAT). The tested results showed that sampling methods have a significant effect on deposition results. The number of spray deposits and coverage on the sampling pole were 35 and 40% higher than those on the sampling leaves, respectively. The deposition and control efficacy gradually increased as the water application volume increased. The control efficacy at 14 DAT under different water application volumes was in the range of 59.4–85.4%. These data suggest that UASS spraying can be used to achieve a satisfying control of FAW, but the control efficacy of the water application volume of 30.0 and 22.5 L/ha did not differ significantly. Considering work efficiency, a water application volume of 22.5 L/ha is recommended for field operation.

Field evaluation of a six‐rotor unmanned agricultural aerial sprayer: effects of application parameters on spray deposition and control efficacy against rice planthopper

“…This reveals significant potential for improving the uniformity of pesticide deposition distribution applied by UASS. These findings align with prior research, demonstrating that the CV of UASS can exceed 40%, even reaching 100%–120% for both single and multiple swaths 46–48 . Variability in pesticide deposition distribution is a common occurrence in field applications due to the unique characteristics of these systems.…”

Field evaluation of spray drift and nontargeted soybean injury from unmanned aerial spraying system herbicide application under acceptable operation conditions

“…From Figs 3 and 4, the CV values of the six‐rotor UASS sprayer within a single swath (48.0–83.4%) were observed to be much higher than values for conventional boom sprayers, indicating a poor distribution uniformity measured at the top of the artificial rice plants. These results are in line with those of previous studies, which have shown that the CV values of UASS were almost above 40% and even reached 100–120%, for both a single swath and multiple widths 18,20,42–46 . This is a common phenomenon in current UASS field application operations in China, determined by the characteristics of the UASS itself.…”

“…These results are in line with those of previous studies, which have shown that the CV values of UASS were almost above 40% and even reached 100-120%, for both a single swath and multiple widths. 18,20,[42][43][44][45][46] This is a common phenomenon in current UASS field application operations in China, determined by the characteristics of the UASS itself. Unmanned aerial sprayers normally use ultra-low volume (ULV) and very-low volume (VLV) applications, and the fine droplets are greatly influenced by rotor airflow and external natural wind.…”

Impact of Operational Parameters on Droplet Distribution Using an Unmanned Aerial Vehicle in a Papaya Orchard

“…This is explained by the fact that during the applications, the so-called "umbrella effect" occurred, in which the leaves in the upper and middle layers prevented the increase in coverage, density, and deposition of drops in the lower layer and fruit clusters. The authors of [46], using a UAV equipped with the XR110-01 and -015 nozzles, to control the caterpillar (Spodoptera frugiperda) on corn plants, observed that coverage and droplet deposition were higher in the upper layer and lower in the lower layer. Other studies support this statement using UAV-applied flat-fan nozzles, such as on citrus [47] and on pigeon pea [48].…”