Small scale fungicide delivery equipment to manage early blight in three types of tomato

Authors: BARLOW, WILLIAM - University Of Kentucky; Pfeufer, Emily

Submitted to: Plant Health Progress
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/2021
Publication Date: 8/26/2021
Citation: Barlow, W.B., Pfeufer, E. 2021. Small scale fungicide delivery equipment to manage early blight in three types of tomato. Plant Health Progress. 23(1):45-48. https://doi.org/10.1094/PHP-06-21-0091-RS.
DOI: https://doi.org/10.1094/PHP-06-21-0091-RS

Interpretive Summary: Early blight is a common tomato disease affecting both small- and large-scale production. Fungicide applications and the type of tomato grown are important ways early blight can be managed. Fungicide effectiveness may rely on the application equipment used, which vary in cost and differ among small- and large-scale growers. At the same time, two factors that influence how growers choose tomato varieties are consumer demand and how easily a variety becomes diseased. These studies were conducted to identify trends in how severely early blight affects different tomato types, and to compare how well different small scale sprayers reduce early blight within tomato types. Results indicated that the determinate tomato varieties tested generally developed more early blight than the indeterminate and cherry/grape tomato varieties tested. Further, for tomatoes that developed high levels of early blight, a compressed gas sprayer was the only small scale equipment option tested that reliably reduced disease. Tomato growers benefit from this information by understanding that compressed gas sprayers may be a more effective spray equipment option than hand-pumped or mister-blower options on early blight-prone varieties. Since compressed gas spray equipment ranges from 2-10 times the cost of other tested equipment, growers can use this information to better balance the choice of tomato grown with purchase costs of fungicide application equipment. Further, cooperative extension personnel and crop advisors can use these side-by-side comparisons of commonly available small scale fungicide application equipment as part of grower educational efforts.

Technical Abstract: Management of early blight, one of the most common diseases of tomato, can be challenging for small- and large-scale growers alike, and robust disease resistance is not present in most commonly grown varieties. Comparisons of fungicide application equipment for early blight management have been completed for large-scale growers; however, comparisons have not been conducted of equipment suitable for small-scale plantings. In three trials, small-scale fungicide sprayer options (hand-pumped backpack, gasoline-powered mister-blower, and compressed CO2 backpack sprayer) were compared for effectiveness against early blight in determinate, indeterminate round-fruited, and indeterminate grape/cherry tomatoes. Results suggest that applying fungicides with a compressed CO2 sprayer most consistently managed early blight compared to other sprayer options tested in determinate tomatoes. Statistically significant differences in early blight severity by sprayer were not apparent for indeterminate cherry/tomato types, and were variable for indeterminate round-fruited types. Determinate varieties consistently had the highest early blight severity among the three types of tomato evaluated. These results are influential to small-scale and beginning growers balancing the cost of fungicide application equipment with the type of tomato being grown.