Options for Controlling Volunteer Potatoes

Apr 03, 2020

By Erin Burns and Chris Long

In general, 2019 was a difficult year for field crop growers throughout Michigan. For many potato growers, winter weather set in before all fields could be harvested. Historically, harsh winter temperatures kill tubers that remain in the field after harvest. Although, in regions where winters are mild and soil temperatures are not cold enough to kill tubers left in the field, tubers can survive overwinter and become a serious weed problem the following spring. Not only do volunteer potatoes compete with crops and reduce yield, but they also harbor insects, diseases and nematodes that can infest neighboring or future potato crops.

Volunteer potatoes are difficult to control. Currently, there are no herbicides available that will completely control volunteer potatoes and significantly reduce the number of daughter tubers produced per plant. The Michigan State University potato research team conducted volunteer potato control studies in 2018 and 2019 to investigate potential volunteer control options in corn (Table 1).

Table 1. Postemergence herbicide treatment list for volunteer potato control.
Herbicide trade name	Rate (formulation/A)	Additives
Callisto	3 fl oz	1% COC + 8.5 lb/100 gal AMS
Callisto + Aatrex (atrazine) 90 WG	3 fl oz + 0.5 lb a.i.	1% COC + 8.5 lb/100 gal AMS
Armezon/Impact	0.75 fl oz	1% MSO + 17 lb/100 gal AMS
Armezon/Impact + Aatrex 90 WG	0.75 fl oz + 0.5 lb a.i.	1% MSO + 17 lb/100 gal AMS
Laudis	3 fl oz	1% MSO + 8.5 lb/100 gal AMS
Laudis + Aatrex 90 WG	3 fl oz + 0.5 lb a.i.	1% MSO + 8.5 lb/100 gal AMS
Acuron Flexi	2 qt	0.25% NIS
Acuron Flexi + Aatrex 90 WG	2 qt + 0.5 lb a.i.	0.25% NIS

COC = crop oil concentrate, AMS = ammonium sulfate, MSO = methylated seed oil, NIS = nonionic surfactant, treatments that can be applied to seed corn. Corn inbreds vary in their sensitivity to herbicides, thus it is important to consult the seed company on their inbred tolerances to the herbicides included in Table 1.

Results in Figures 1-3 highlight two important facts. First, the addition of atrazine to herbicide treatments improved control. Second, as the size of volunteer potatoes increased, control decreased. When applications were made to small volunteers (less than 6 inches), 60% of treatments resulted in one or no daughter tubers produced per plant. When applications were made to medium (6-12 inches) or tall (more than 12 inches), only 25% and 0% of treatments resulted in one or no daughter tubers produced per plant (Fig. 1). A similar trend was observed in mean daughter tuber weight (Fig. 2).

Figure 1. Mean daughter tubers produced per plant at the Montcalm Research Center location. Mean tubers (plant-1) values followed by the same letter are not significantly different (P ≤ 0.05).

Figure 2. Mean daughter tuber weight at the Montcalm Research Center location. Mean tuber weight values followed by the same letter are not significantly different (P ≤ 0.05).

In addition to the treatments outlined in Table 1, we also tested glyphosate in both years. In 2018, glyphosate provided little control. In contrast, in 2019 glyphosate was highly effective at controlling volunteers. Given this variability, if glyphosate is applied to control volunteers, scout fields two weeks after application to ensure sufficient control.

Finally, keep in mind your plans for future rotational crops and consult Table 12 – Herbicide Crop Rotation Restrictions in the 2020 MSU Weed Control Guide for rotation restrictions.

The Michigan Potato Industry Commission supported this research. For full study details and additional results, see the 2019 Michigan Potato Research Report.

Source : msu.edu

Video: Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe.

That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here -- and boy, have there been some abrupt changes as of late.

El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator.

Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That's where we're at right now.

Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer.

But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño.

Over the last few weeks, unusually strong bursts of westerly winds farther west in the Pacific -- where sea surface temperatures are warmer than average -- have been observed. There is a chance that this could accelerate the warming of those eastern Pacific waters and potentially push us into El Niño sooner than usual.

If we do enter El Nino by spring -- which we'll define as the period of March, April and May -- there are some long-term correlations with our weather here in Northeast Wisconsin.

Looking at a map of anomalously warm weather, most of the upper Great Lakes doesn't show a strong correlation, but in general, the northern tiers of the United States do tend to lean to that direction.

The stronger correlation is with precipitation. El Niño conditions in spring have historically come with a higher risk of very dry weather over that time frame, so this will definitely be a transition we'll have to watch closely as we move out of winter.