Rapid crop growth - some moisture shortages

This information was summarized from a July 9 teleconference with ISU extension field specialists in crops.

  • Rainfall has been scarce during the last several weeks. Some areas of the state have not had rain for 4 weeks. Moisture stress has caused corn leaves to roll-up in some fields for the past 10 days.
  • Early-planted corn is beginning to tassel. The late-planted fields are V4 to V5. Some fields, mainly in the east central part of the state, continue to show potassium deficiency symptoms, with plants having shortened internodes. A few scattered fields are over threshold for first-generation European corn borer and are being sprayed. Grasshoppers are in field borders in northwestern Iowa.
  • Early-planted soybean fields are beginning to bloom. Fields replanted several weeks ago are only at V1 to V2 growth stage. Cultivation and spraying for weeds continues. Some waterhemp plants have gotten too large for cultivation. The first-generation bean leaf beetle population is increasing. In northeastern Iowa, Brian Lang reported that the soybean aphid was spreading in a field that he has been monitoring.
  • Second-cut alfalfa harvest is continuing and the hay is shorter than normal. Some fields have potato leafhoppers over threshold and arebeing sprayed.
  • Much of the oat crop is being harvested for forage. The fields that will be harvested for grain are ripening and generally in the soft dough stage.
  • Winter wheat is being harvested. Yields range from 45 to 85 bushels per acre.

This article originally appeared on page 149 of the IC-486(18) -- July 16, 2001 issue.

Updated 07/15/2001 - 1:00pm