Effect of the spray volume adjustment model on the efficiency of fungicides and residues in processing tomato

Abstract

This study compared the effects of a proportionate spray volume (PSV) adjustment model and a fixed model (300 L/ha) on the infestation of processing tomato with potato late blight (Phytophthora infestans (Mont.) de Bary) (PLB) and azoxystrobin and chlorothalonil residues in fruits in three consecutive seasons. The fungicides were applied in alternating system with or without two spreader adjuvants. The proportionate spray volume adjustment model was based on the number of leaves on plants and spray volume index. The modified Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was optimized and validated for extraction of azoxystrobin and chlorothalonil residue. Gas chromatography with a nitrogen and phosphorus detector and an electron capture detector were used for the analysis of fungicides. The results showed that higher fungicidal residues were connected with lower infestation of tomato with PLB. PSV adjustment model resulted in lower infestation of tomato than the fixed model (300 L/ha) when fungicides were applied at half the dose without adjuvants. Higher expected spray interception into the tomato canopy with the PSV system was recognized as the reasons of better control of PLB. The spreader adjuvants did not have positive effect on the biological efficacy of spray volume application systems. The results suggest that PSV adjustment model can be used to determine the spray volume for fungicide application for processing tomato crop.

Effects of a multi‐functional adjuvant on efficacy of methoxyfenozide (SC24%) and spinosad (SC24%) to control the European grapevine moth, Lobesia botrana

“…There is little research into the effects of the tested adjuvant in the literature and we only found two published papers. Ratajkiewicz et al (2016) reported that when that multi-functional adjuvant was used with a half dose of chlorothalonil and azoxystrobin against potato late blight caused by Phytophthora infestans (Mont.) in tomato, the adjuvant reduced residues in tomato under the fixed model spray volume.…”

NRC Designs—New Tools for Successful Agricultural Experiments

“…Based on the infestation of the plants, a determination was made of the influence of the constant (300 L/ha, SV300) and variable (PSV) spray volume and adjuvants when alternating azoxystrobin and chlorothalonil for coarse spraying with the IDKT12003 twin-jet induction nozzle. The variable spray volume (PSV) was calculated from the number of leaves per plant according to the model presented in the paper [38]. In accordance with the methodology described in the article, two fungicides were used in the study alternatively: azoxystrobin (methyl (E)-2-[2-[6-(2-cyanophenoxy)pyrimidine-4-yl]oxyphenyl]-3-methoxyprop-2-enoate, Amistar 250 SC; Syngenta Ltd., Guildford, UK) at a dose of 125 g/ha (50% of the recommended dose) or chlorothalonil (2,4,5,6-tetrachlorobenzene-1,3-dicarbonitrile, Gwarant 500 SC; Arysta LifeScience S.A.S., Noguères, France) at a rate of 625 g/ha (50% of the recommended dose).…”