ISSUE 16 August 22, 2002
SOYBEAN APHID ACROSS NORTH DAKOTA ?
We have reached a point where soybean aphid is dispersing widely across the state. We are seeing a similar situation as last year when the aphids migrated into our region from southern Minnesota. Looking in fields west of the valley, aphids are being found on field margins. There are usually only a couple of aphids on infested leaves. What is happening is the result of winged females flying to new sites, landing on leaves, giving birth to one or two aphids, and moving on to other leaves, plants, or fields. We would not expect this aphid dispersal to result in any future yield impact.
The following highlighted counties represent reported infestations from the season so far. There are still reports coming in of other finds. If you know of infestations in other counties not highlighted here, drop me a note and will add the information to our records. I believe the counties between the eastern counties and north central counties, however we donít have a record of anyone reporting them at this point.
GRASSHOPPERS, FLEA BEETLES, AND SUNFLOWER INSECTS
Grasshoppers are still the most bothersome insects in the region. Reports are still coming in of people treating field margins for the migrating adults. If treatments are still being considered, be sure to read the label of the selected insecticide and be sure there will be no problems with the post harvest interval. As crops approach maturity, many of the insecticides available on our crops are going to have days till harvest of 14 or more days. Keep track of where these adults are concentrating. Egg laying should be underway. These locations are where you should see the nymphs hatching next May.
Canola flea beetles have been out in force. The black crucifer flea beetle adults emerge from the soil beginning in late July and feed on crucifer plants, particularly the canola. Sometimes the feeding on green pods can cause shattering problems, but generally, controlling these adults is not necessary. Some of the biggest problems in recent weeks has been with later planted fields that are still green while neighboring fields are being swathed. Areas where large numbers of flea beetles are active should alert growers to the need for insecticide seed treatments for next year.
Finally, if sunflowers are still blooming in fields, continue to watch for red seed weevil. They have been reported in high numbers in the south central counties. Fortunately, this activity should be winding down soon.
OBSERVING THE 40TH ANNIVERSARY OF SILENT SPRING
In a recent issue of Reason magazine, author Ronald Bailey wrote that "The great cancer scare launched by Rachel Carson and perpetuated by her believers ever since, should have been put to rest by the 1996 National Academy of Sciences report on carcinogens in human diets. That report concluded natural diet components may prove of greater concern than synthetic with respect to cancer risk." Bailey concluded that Carson may have been ignorant of facts at the time, "but after four decades in which tens of billions of dollars have been wasted chasing imaginary risks, her intellectual descendants don't have the same excuse."
The entire article can be accessed at
Ronald Bailey is Reason's science correspondent and the editor of Earth Report 2000: Revisiting the True State of the Planet(McGraw-Hill)
For other topics pertaining to agriculture and the role pesticides play, visit the CropLife America web site at:
CropLife America promotes the environmentally sound use of crop protection products for the economical production of safe, high quality, abundant food, fiber and other crops.
Or, for some interesting tidbits from the "junk-science" arena, visit this site for a short-course on learning about what junk science is, how to recognize it and what you can do about it.