Vegetable Scouting Report for week of July 10-15-from
Looking at many corn fields we are
finding something that goes against what we usually find in the field.
European corn borer (ECB) adults normally fly between the end of May and the
middle of June. After the flight, because the adults find the most mature
corn most attractive, larvae populations are usually highest in the most mature
corn. The percentage of ECB worms in later plantings decreases until the
second flight begins in late July. This summer, we are finding more ECB
worms in the second and third plantings than the first plantings. I think
this is because of all the rain we had in May and June. We had an up and down
flight where normally the flight peaks and then numbers go down after
that. This is a guess but in any case, we are seeing higher percentages
of ECB in later corn plantings as we go along.
It is quick and easy to find out how much ECB you have in your fields. Walk through the field and stop randomly at 5 locations. Inspect 5 plants at each location for ECB feeding damage - holes, saw dust and windows in the leaves around the tassel. Scouting is quick because you are only looking for the presence or absence of feeding damage. If you see damage on a plant, keep a running count of that number. When you've inspected 25 plants, multiply the number of plants with holes times four and this gives you a percentage of field infestation. If you are over 15% than a control is called for.
Scout your fields for tassel emergence. With the warmer weather, the tassels are opening quickly and since the ECB larvae do not like the heat, they do not stick around very long. After tassel, the larvae either drop down to the ear or they bore into the stem making them more difficult to eliminate. When you see around 30-40% of the field with the tassel just starting to stick out, make your first application. Since the field will be coming quickly, the time before your second application will be shorter, maybe 2-3 days. Keep an eye on your fields that are about to come into tassel as sprays at tassel are the most effective at controlling the worms. For organic growers, Entrust, the organic formulation of Spintor, works very well.
a look at this issue of New Ag Network-a newsletter for and by
issue –July 12,
[log in to unmask]">What’s causing my vegetables to
[log in to unmask]">Organic matter amendments and the
development of disease suppressive soils
[log in to unmask]">Economics of organic field crops
[log in to unmask]">United States and regional supply of
certified organic field crops and livestock
[log in to unmask]">Asian soybean rust update for organic
On August 23, 2006
For information on the agenda, registration and directions please
visit the web site www.mottgroup.msu.edu
or call Vicki
Organic Vegetable and Crop Outreach Specialist
C.S. Mott Sustainable Food Systems
303 Natural Resources Bldg.