Published on Sep. 12, 2022

Updated on April 16, 2024

Contents:

• Be on the Lookout for Spotted Lanternfly (SLF)

Be on the Lookout for Spotted Lanternfly (SLF)

In the past 60 days SLF has been reported in Northeast Indiana and Michigan. In both of these cases the movement can likely be attributed to hitchhiker events, where SLF egg masses or potentially nymphs or adults of SLF were moved on materials via some type of vehicle transport. Please inform your harvest crews of SLF. At this time of year the adult life stage of SLF is prominent (Figure 1).

For additional information, please view the pdf from the Missouri Depart-ment of Agriculture. Please pass the information to harvest crews.

Powdery Mildew

Grape growers as well as my visual observations confirm that some vineyards are experiencing powdery mildew outbreaks. If your vineyard is experiencing a powdery mildew outbreak after the application of a DMI fungi-cide (Frac Code 3) then consider that the powdery mildew may have developed resistance. Powdery mildew resistance to DMI inhibitors was confirmed in Missouri in 2021. Some of the common DMI fungicides include: Mettle, Procure, Rally, TebuStar (tebuconazole) and Vintage. Alternative fungicides to control powdery mildew are: Merivon Xemium (Frac 7+11), Quintec (Frac 13), Topsin M (Frac 1), Torino (Frac U6) and Vivando (U8).

Some of these alternative fungicides have lengthy pre-harvest intervals (Table 1). Be aware of these PHI’s as harvest nears. Other alternatives for control are to apply a strobilurin fungicides such as Abound, Flint, Pristine or Sovran. Do not apply stobilurin fungicides if you have already made two applications this growing season. Also do not apply strobilurin fungicides if your grapevines are heavily inundated with powdery mildew. Extremely high powdery mildew populations coupled with a very selective fungicide such as the strobilurins increases the potential for selecting for powdery mildew resistant populations. In addition, sulfur is an excellent preventative for powdery mildew. However, sulfur has limited usefulness if powdery mildew has become established throughout a vineyard. Be sure to keep sulfur off of sulfur sensitive cultivars such as Chambourcin and Norton.

Table 1. Some alternative fungicides for controlling powdery mildew in grapes.

Please scout your vineyards on a regularly scheduled basis in an effort to manage problem pests. This report contains information on scouting reports from specific locations and may not reflect pest problems in your vineyard. If you would like more information on IPM in grapes, please contact Dean Volenberg at 573-882-0476 or 573-473-0374 (mobile) or volenbergd@missouri.edu

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