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OSU Extension

College of Food, Agricultural, and Environmental Sciences

June 18, 2024 - 9:16am --

With the growing season underway, there are some trends that have made late spring a challenge for area growers and farmers. As some of you may have noticed, everything seems to be “early” this year in respect to certain developmental progress observed in primarily crop stages and insect development. This observation is consistent with our current standing for accumulated Growing Degree Days. The growing degree days, or GDD as they are commonly referred to, are a measurement of the growth and development of plants and insects during the growing season. Development does not occur unless the temperature is above a minimum threshold value, or what is also referred to as the base temperature. This base temperature can vary for different organisms and is determined through research and experimentation.

In Ohio, we have a very useful tool to track GDDs and look at the corresponding phenology. Ohio State has an interactive site that allows you to enter in your zip code and look at the amount of GDDs that have accumulated, as well as the plants that are blooming, or insects that are emerging based on the relative number of GDDs. Check out this website for more information and to view the Phenology Calendar: Another way to track the weather and GDDs here in Wayne County is the OARDC weather station, which can be found here:

It is important to note that while the actual number associated with GDD is based on weather stations across Ohio, there can be some differences based on microclimates, but the sequence of activity is always in the same order. As you use GDD, it is always recommended to get outdoors and compare what the website is estimating to be happening versus what you are seeing. As of writing this article, our accumulated GDD count sits at 931, while the historical average for this date is 769.

Accordingly, it is important to be out and checking your crops, both agronomic and horticultural, for insect damage. Early season pressure has been observed from the following pests: flea beetle (multiple species), Colorado potato beetle, cucumber beetle, Japanese beetle, aphids, mites, thrips, slugs, potato leaf hoppers, imported cabbageworm, cutworms, and several other lepidopteran pests. Early season damage can stunt growth, reduce yield potential, and potentially lead to introduction of vectored diseases such as bacterial wilt from the cucumber beetles, or several viruses vectored by thrips, aphids, and flea beetles.

Reference materials such as the Midwest Fruit Pest Management Guide, Midwest Vegetable Production Guide, and the Insect Management Guide for Field Crops (joint publication from Ohio State and Michigan State) can all be referenced for specific management recommendations. These can be found online, or through your local county extension office.

Frank Becker is the Agriculture and Natural Resources Extension Educator with Ohio State University Extension – Wayne County, and a Certified Crop Adviser, and may be reached at 330-264-8722 or
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This article was previously published in The Daily Record.