Water Hemp Emergence

The use of Growing Degree Days allows for approximation as to when crops have reaches certain development stages, or when certain insects or weeks may emerge.  Through research a base temperature can be determined when a development of the plant or an insect needs to develop then add temperatures above that set point up.  For example the base number for Corn is 50 degrees.  So if the low is 50 and the high was 70 degrees, the average temperature that day was 60 degrees.  The base of 50 subtracted from 60 would yield 10 Growing Degree Days.   One noxious and resistant weed to most herbicides is Water Hemp.  Water Hemp requires around 350 Growing Degree Days with a base temperature of 48 degrees.  At our current pace that plant in many areas may begin to emerge by the end of the month.

Daryl Ritchison