Tools to help the Smart Gardener understand weather and pest-related stresses in the landscape

Enviro-weather online tools help provide answers to statewide landscape problems.

EnviroweatherA call came into the Michigan State University Extension state garden hotline (888-678-3464) in late April 2012. A woman from Kent County was worried that a disease caused her Japanese maple to wilt overnight. When it was explained to her that this was likely the result of a hard spring frost the night before, she refused to believe it had gotten that cold. A quick check of weather conditions through the MSU Enviro-weather website showed that local temperatures in Kent County dropped to 25 degrees twice over a three-day period. Sharing the recorded temperatures with the caller provided data that helped her realize the Japanese maple was damaged by freezing temperatures.

Garden hotline volunteers and staff have found the Enviro-weather website ( a valuable tool for answering questions from homeowners across the state. Tools at this site include information on temperatures, rainfall, degree days and weather forecasts. You can compare weather conditions from previous years and even predict when an insect hatch will occur for different areas of the state. The usefulness of this management tool lies in the large number of weather stations across the state providing information on local conditions.

A Washtenaw County resident contacted MSU Extension two years ago to better understand the timing of pesticide controls for an insect killing the top leader of his pines. The culprit was a small beetle called a white pine weevil. He wanted a date when he could spray each year to control this pest. Because pest development is based on temperatures, the date adult weevils begin to lay eggs on pines can vary from mid-March to mid-April. He was directed to the Enviro-weather website where he monitored the development of the weevil based on growing degree days (GDD). Local weather stations helped him monitor when the degree days reached 25, which is the point when adult weevils are actively feeding and laying eggs on the pines. He now uses this site each year to monitor for the correct timing of control measures based on GDD and has achieved great results.

A small backyard fruit grower in Livingston County was able to follow forecast and temperature information on the Enviro-weather website to determine if he needed to use sprinklers through the night to protect his fruit trees from a late spring freeze in 2012.

These tools are useful to everyone and easily relate to needs in the home landscape. Whether monitoring degree days to determine the hatch of a crawler stage of euonymus scale or evaluating temperature and rain conditions from across the state, the Enviro-weather site gives a means of precisely managing insect pests and diseases.

For a more in-depth look at the Enviro-weather site, see the article, “Accessing growing degree days with Enviro-weather” by Beth Bishop, Enviro-weather coordinator.

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