Potato Extension
Speical edition of the NDSU Potato Blightline
Late blight has been confirmed in a potato sample collected in Pembina County, ND. We do not yet know the genotype of the isolate. Late blight severity values in our area continue to increase and conditions remain favorable for late blight because of the wet conditions and spotty showers. Growers should continue to scout frequently for late blight and apply protectant fungicides on a seven-day schedule, including fields that have been abandoned due to water damage. Scouting is especially important in fields along the Canadian border and in wet fields in northeastern ND and northwestern MN that may be exposed to late blight spore showers. This late blight has the potential to spread to unprotected and abandoned fields near the infected field.
Blightline Aug 22, 2016
Late blight has not been reported in ND or MN. Late blight severity values in our area continue to increase and conditions remain favorable for late blight because of the wet conditions and spotty showers. All sites except Mandan and Williston have exceeded the threshold value of 15.
NPPGA Field Day 2016
North Dakota State University and the University of Minnesota potato research will be highlighted during the Northern Plains Potato Grower Association Field Day on Thursday, Aug. 25. This year, the field day tour will travel to three locations. The day will begin at 7 a.m. with breakfast at Hoverson Farms near Larimore. Lunch and research presentations will be at the Forest River Colony near Inkster at noon. Also scheduled is a field tour of the irrigated research trials. The last stop will be at Oberg Farms near Hoople starting at 5:30 p.m. The final stop will include research poster presentations and an evening meal.
Blightline August 15
Late blight has still not been reported in ND or MN despite very favorable conditions. Late blight severity values in our area continue to increase and conditions remain favorable for late blight because of the wet conditions and spotty showers. All sites except Linton, Mandan and Williston have exceeded the threshold value of 15. Severity values are high in all other locations and conditions have been favorable in southeastern ND and southwestern MN the past two days.
Management of Potato Psyllids
Adult potato psyllids have been detected in some fields in western and south central North Dakota potatoes. This insect is mainly found in the Rocky Mountain states. Potato psyllids are believed to overwinter in the southern most U.S. states and Mexico and re-establish to northern locations in the summer via wind dispersal. They are not known to overwinter in North Dakota. Potato psyllids are of principal concern because they can transmit the Liberibacter bacterium which causes Zebra chip.
Blightline August 5, 2016
Late blight has not been reported in ND or MN. We are looking forward to good drying weather after the rounds of excessive rain and damage to fields. Late blight severity values in our area continue to increase and conditions remain favorable for late blight because of the wet conditions.
CPB Management
There may be a couple of reasons for this, the cool wet early summer probably slowed down beetles and decreased at-plant insecticide efficacy, we have been recording increased tolerance to neonicotinoid insecticides, and the delayed emergence of CPB recorded over the last few years in central MN may now be happening in both locations....For whatever reason, the issue is now management of mixed stages of larvae and adults or simply late season adults, depending on your location. Either way, we're fighting a foliar battle now.
Blightline July 25, 2016
Late blight has not been reported in ND or MN. Finally, we are looking forward to good drying weather after the rounds of thunderstorms last week that added more rain to already too wet fields. The excessive rain dramatically increased late blight severity values in northern and eastern ND and northwestern MN, and many sites have exceeded the threshold value of 15. This is especially true in non-irrigated fields. Late blight can move long distance with thunderstorms, and it is possible that late blight can leapfrog from western MB to northern ND where abundant water and conditions favorable for late blight are present. Growers should scout frequently for late blight and apply a protectant fungicide to fields, including fields that may be abandoned due to water damage.
Aphid Alert July 18-22
The aphid numbers remain relatively low this week but as the grain matures, look for aphids moving into potatoes. We expect some additional trap reports early next week so we'll update when we get them in.
Blightline July 19, 2016
Late blight has been reported in western Manitoba according to Vikram Bisht of Manitoba Agriculture. Late blight has not been reported in ND or MN. Late blight severity values have increased the past few days in north central ND and northwestern MN and conditions have been favorable for late blight due to the continuing rains.
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