By Pam Brown, Urban Horticulture Agent, Pinellas County Extension

This time of year we are thinking about how a little fertilizer could green up our St. Augustine lawn. But, if you overdo the fertilizer, you may be growing more than grass.

A new University of Florida study suggests that by repeatedly using large amounts of nitrogen fertilizer, you can create just the right environment for an explosion of Southern chinch bugs. Chinch bugs are the number one insect pest of St. Augustine, the state’s most popular lawn grass.

In the study, Southern chinch bugs produced the most eggs on St. Augustinegrass fed the equivalent of 2 pounds nitrogen per 1,000 square feet per month. This is a worst-case scenario, but not unrealistic considering that people sometimes over fertilize in their zest to have the greenest lawn in the neighborhood.

The turfgrass experts at the University of Florida advise us to use no more than 1 pound of slow-release nitrogen fertilizer per 1,000 square feet of lawn, a recommendation found in the document “St. Augustinegrass for Florida Lawns,” available at http://edis.ifas.ufl.edu/LH010.

These findings were presented in Jacksonville on March 14, 2008 at an Entomological Society of America meeting.

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