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Five key periods during the growing season to scout small grain fields By Ian MacRae, Jochum Wiersma With marginal crop prices and higher fuel costs that will put the squeeze on
many crop production budgets, ask yourself this question every time you consider applying a pesticide this growing season: Why pay to control something that's not there?
Why indeed. Thus, you gotta scout your fields. Scouting for insects, scouting for weeds, scouting for disease; it seems you hear about it at almost every extension meeting. It must seem sometimes like we
think growers have nothing better to do with their time. We all have lives away from the field (it only seems we don't!). Yes, it's time consuming. Nevertheless, scouting is more important than ever,
since it represents a real opportunity to save on inputs. To properly scout a field for any pest, you should plan on about an hour for every 80 acres. Sounds like a lot of time, but let's compare it to one of
the least expensive pest control options: Some insecticide applications, when piggybacked onto other applications, can cost as little as $3/acre (so about $240/80 acres). By not taking the one hour to scout that
80 acres, you've made the decision that scouting time is worth $240/hr. Planning your scouting efforts can drastically decrease the amount of time you spend looking for pests in your fields. By looking
for weeds, insects and diseases at the right time, you can streamline your scouting efforts. There are 5 major periods you should scout small grain fields listed in the chart below.
Timing
Stage |
Growth
Stage
(Zokaks) |
Agronomic |
Scouting Activities
Weeds Insects |
Diseases |
2-Leaf
Stage |
12 |
Stand Count |
Scout for Weeds |
-- |
-- |
4-5 Leaf Stage |
14-15 |
Est. yield (If jointing has started) |
Scout for weeds |
Scout aphids & Grass- hoppers |
Scout for leaf diseases (powdery mildew) |
Flag Leaf
Emergence |
37 |
-- |
-- |
Scout for aphids & other insects (army worms) |
Scout for leaf diseases |
Anthesis |
60 |
Estimate Yield |
-- |
Scout for OWBM |
Evaluate need for FHB treatment |
Physio-
logical Maturity |
90 |
-- |
Evaluate for pre-harvst herbicide |
-- |
-- |
Commercial scouts are an excellent source for much of this information. However, there are certain pests of small grains that are either linked to
time sensitive treatments or must be scouted for under specific conditions. For example, growers may want to augment professional monitoring by scouting themselves for insects like orange wheat blossom midge or
aphids. Scouting is a time consuming activity, but there are ways to maximize scouting efficiency. And, done correctly, it can help avoid unnecessary input costs.
(MacRae is an entomologist at the University of Minnesota, and may be contacted by e-mail:
macra002@maroon.tc.umn.edu. Jochum Wiersma is a small grains specialist at the U of M, and may also be contacted by e-mail: Jochum.J. Wiersma-1@tc.umn.edu) |
