TechNotes Tips - 01.31.02

Growing degree-day (GDD) is a means of quantifying seasonal accumulation of temperature and is commonly expressed as average daily temperature minus a base temperature. The base temperature may vary but often 50 F is used. GDD’s do not have a unit associated with them and by themselves do not mean much. However, GDD are often associated with pest and plant developmental stages. Developmental stages of insect pests are often associated with GDD. For those living in California there is a site where common insect pest development of both ornamentals and crops are associated with GDDs. See:
http://www.ipm.ucdavis.edu/

Later issues will report GDD with associated insect pest development.

See GreenCast website to view models that incorporate degree day information into pest occurrence predictions.

Crabgrass will be germinating soon for most of the southeastern United States. This region includes States like Alabama, Mississippi, Georgia and South Carolina. Winter annual weeds are actively growing in the southeastern United States. In areas of heavy infestation, post-emergent herbicide applications for these weeds would be recommended.