Cost
Ben Werling, Michigan State University Extension, and Zsofia Szendrei, MSU Extension, Department of Entomology - January 20, 2015
The northeast onion industry has a diverse chemical toolbox and effective surfactants to manage onion thrips.
The Midwest and northeast onion industry now has an excellent toolbox of chemistries with different modes of action that, if used right, could provide durable control of onion thrips into the future. By using the right products with the right surfactants at the right time, you can accomplish this goal while minimizing cost.
Research over the past decade has identified a short-list of effective insecticides from the many formulations labelled for thrips control in onions, including Radiant, Lannate, Movento and Agri-Mek (Table 1). Importantly, old standbys including Warrior are still labelled, but have been rendered ineffective by resistance in some onion growing regions. Recent work shows that Exirel, an insecticide with a distinct mode of action, can be an effective addition to your insecticide rotation. This means now there are five distinct modes of action which, if used in rotation at the right time, will reduce chances that our industry will face the resistance-related control failures that have occurred in the past.
Product
a.i.
Chemical class
IRAC
Radiant SC
spinetoram
spinosyns
5
Lannate LV
methomyl
carbamates
1A
Agri-Mek SC
abamectin
avermectins
6
Movento
spirotetramat
tetramic acid
23
Exirel
cyantraniliprole
diamides
28
The right surfactants and tank-mix partners
The right surfactant can make the difference between excellent control and economic damage. Past work showed that a non-ionic surfactant applied at 0.5 percent v/v (percent surfactant out of total solution volume) greatly improved Movento’s ability to control thrips. Recent work has shown that a variety of other surfactants can accomplish this task; methlyated spray oils (MSOs), organosilicone, terpene, mineral oil and fatty acid products have proven equally effective in Michigan State University and Cornell University trials (Table 2).
Product
Chemical
Rate
JMS Stylet Oil
mineral oil
1.5% v/v
Purespray Green
mineral oil
1 gal/acre
MSO
methylated spray oil
0.25% v/v
Requiem 75EC
terpene
1 qt/acre
Dyne-Amic
non-ionic surfactant
0.25% v/v
Induce
non-ionic surfactant
0.5% v/v
M-Pede
K-salts of fatty acids
2% v/v
Silwet L-77
organosilocone
0.25% v/v
In addition, research from MSU showed that reducing the rate of organosilicone and MSO surfactants by half from 0.5 percent v/v to 0.25 percent did not compromise control. This means there are a variety of equally effective surfactants you can choose from, which can be used at reduced rates in some cases. As important as your choice of surfactant, research from MSU and Cornell has shown that tank-mixing chlorothalonil-based fungicides with Agri-Mek and Movento reduces their efficacy. However, fungicides such as Dithane, Rovral, Scala and Quadris can be tank-mixed without loss of efficacy.
Choosing the right products and surfactants is your first step towards obtaining effective thrips control. The next step is to make sure you apply them at the right time to ensure efficacy, delay resistance and save money.
For more from Michigan State University Extension, see Part 2 of this series: Cost-effective onion thrips control program 2: Apply at right time based on scouting and thresholds.
Dr. Szendrei’s work is funded in part by MSU’s AgBioResearch.
This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).
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The right productsProducta.i.Chemical classIRAC The right surfactants and tank-mix partnersProductChemicalRateMichigan State University ExtensionPlease tell us why?