NDSU Extension - Ramsey County


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June 4, 2012 Agriculture Column



The shot of rain we received over the last couple of weeks has sure perked the crops.  Crops in general are looking very good.  The storms that went through over the weekend did leave some very differing amounts, even only a ¼ mile away could mean a difference of an inch.  There was some reports of hail with some amounts adding up.  I have also heard of some canola replanting happening from the flea beetle so keep your eyes open.


Get Ready to Collect Leafy Spurge Flea Beetles

Leafy spurge flea beetles (Aphthona species) are an effective means of controlling leafy spurge in North Dakota. This group of flea beetles is host-specific to the leafy spurge plant, which makes them an ideal biological control choice. The accumulated growing degree days (AGDD) for sunflower (base of 44°F) can be used as a guide to determine when to begin scouting for adult flea beetles. Begin scouting for adult flea beetles when the AGDD approaches 1,000. Flea beetles should be collected between 1,200 and 1,600 AGDD using the sunflower GDD model from NDAWN. We have not accumulated enough GDD yet in North Dakota for collecting adult leafy spurge flea beetles. Collecting typically begins in mid to late June most years. Even with the recent cool weather we are still ahead of the calendar for AGDD.  Adult flea beetles can be collected with sweep nets. After late July (or 1,600 AGDD), flea beetles begin to lay eggs and should not be moved or collected. Leafy spurge flea beetles typically take three to five years to establish and impact leafy spurge infestations.

To find collecting sites for leafy spurge flea beetle, contact your local county extension agent or weed control officer. A listing of the weed control officers by county can be found on the North Dakota Weed Control Association website: http://ndweeds.homestead.com/10_County_City_Weed_Boards_Directory.pdf


Janet J. Knodel Extension Entomologist


Rains Bring Greater Risk of Small Grain Fungal Diseases

The NDSU Disease Forecasting site (www.ag.ndsu.nodak.edu/cropdisease) indicates that recent rains across the state have activated a “Yes” for favorable weather for tan spot infection.  Currently, very cool temperatures will slow disease development, but as the week warms up, individuals should check this website to determine if NDAWN locations are indicating many continuous days of infection risk.  The site has not indicated favorable leaf rust infection periods yet, and no wheat leaf rust has been reported in the state as of May 29.

Fusarium head blight (scab) risk for winter wheat: Moderate to high risk of Fusarium head blight for susceptible winter wheat cultivars is occurring now (May 29) in parts of northern ND, and in an area northwest of Jamestown, as indicated by choosing the flowering stage at the above website, or by checking the national FHB forecasting site, at www.wheatscab.psu.edu.  The risk now is for any winter wheat crops that might be flowering or near flowering.  Because most winter wheat cultivars are susceptible to Fusarium head blight, an application of Prosaro at 6.5 fl oz or Caramba at 13.5 fl oz per acre is recommended, as these two products provide the greatest reduction in head severity and reduction in DON (vomitoxin).  However, with frost advisories across much of the state for tonight (May 29), these low temperatures will not be favoring infection, and fungicide application should wait until warmer temperatures return later in the week.  Marcia McMullen Extension Plant Pathologist, Cereal Crop

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