On-Farm Evaluation of Nozzle Types for Peanut Pest Management Using Commercial Sprayers

Abstract

Growers have rapidly adopted auxin-resistant cotton and soybean technologies. In Georgia, growers who plant auxin-resistant cotton/soybean are required to utilize nozzles that produce larger (coarser) droplets when spraying auxin herbicides to minimize potential off-target movement of pesticides. Consequently, these nozzles are also used in peanut (an important rotational crop with cotton) since changing nozzles between crops is uncommon for growers. However, larger droplets can result in reduced spray coverage which may lead to less effective pest control. Therefore, seven on-farm trials were conducted in commercial peanut fields using commercial sprayers from 2018 to 2020 across four different locations in Georgia to compare the spray performance of air-induction (AI) nozzles that produce very coarse to ultra coarse droplets (VMD50 ≥ 404 microns) with non-AI (conventional flat fan) nozzles that produce medium to coarse droplets (403≥VMD50≥236 microns) for pest management in peanuts. For each trial, test treatments were implemented in large replicated strips where each strip represented a nozzle type. For nozzle comparison, XR and XRC represented non-AI nozzles while TADF, TDXL, TTI, and TTI60 represented the commonly used AI nozzles in these trials. Spray deposition data for each nozzle along with disease ratings, weed and insect control ratings were collected in all on-farm trials. Peanut yield was collected at harvest. Results indicated that the AI nozzles produced larger droplets than the non-AI nozzles in all nozzle tests; however, the spray coverage varied among the nozzle types. Nozzle type did not influence pest (weed, disease and insect) control, or peanut yield (p≤0.10) in any of the on-farm trials. These results suggested that peanut growers can utilize these coarser droplet nozzles for pest management in fields with low to average pest pressure during the season. Future research on nozzle evaluation needs to investigate the influence of droplet size, carrier volume, and pressure on coverage and canopy penetration.

"Peanut (Arachis hypogaea) Response to Fungicides and Herbicides Applied using Different Spray Nozzles"

“…However, with the exception of chlorothalonil, fungicides used in the present study were systemic, and nozzle selection most likely less critical. A more detailed study with herbicides and fungicides representing all modes of action and/ or systemic movement with the nozzles used in our study would be informative, especially in North Carolina to corroborate or refute the findings of Virk et al [7]. Depending on constraints growers may have in their communities, application using nozzles that deliver large droplets is an effective practice to avoid particle drift.…”

“…This phenomenon would make coverage of foliage less critical for these fungicides (e.g., azoxystrobin, prothioconazole plus tebuconazole, and pyraclostrobin) while coverage is more important for contact fungicides that are not readily absorbed and forms a layer of protection from pathogens on the leaf surface (e.g., chlorothalonil). Virk et al [7] reported that disease control, including late leaf spot, did not differ when fungicides were applied with range of nozzles similar to the range used in our experiment. Similar to our findings, weed control with herbicides was not affected by nozzle selection over the cropping cycle.…”

“…Kucharek et al [6] reported that efficacy of fungicides was similar when applied using flat fan and hollow cone nozzles for leaf spot disease in peanut. More recently, Virk et al [7] reported similar pest control (e.g., diseases, insects, and weeds) when pesticides were applied using non-air induction and air induction nozzles delivering a range of droplet sizes. While deposition in the canopy was lower when larger droplets were delivered, leaf spot control with fungicides was not compromised.…”

Field Sprayer with Application Rate Control Using Fast Response Proportional Valves under Variable Speed Conditions

“…Higher ground speeds have been shown to lead to a heightened generation of smaller droplets, consequently raising the risk of spray drift. Several studies have documented greater pesticide drift and reduced coverage associated with increases in the travel speed of the tractor [6][7][8][9][10]. In addition, resistance to pests can develop over time, which impairs the effectiveness of pest control.…”

Negative effects on the development of Chrysodeixis includens and Spodoptera cosmioides fed by peanut plants inoculated with entomopathogenic fungi

“…Among the main pests that occur in peanuts, the lepidopterous genera Stegasta , Spodoptera , Chrysodeixis and Helicoverpa are the most important ( Michelotto et al., 2012 ; Pinto et al., 2020 ; Virk et al., 2021 ; Costa et al., 2022 ). In addition to lepidoptera, the peanut crop is severely attacked by thrips, especially the honeysuckle thrips Enneothrips flavens Molton ( Lourenção et al., 2007 ; Calore et al., 2012 ; Michelotto et al., 2012 ).…”