Nourish – March 2019

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Coordinator’s Corner: Did it get cold enough to kill all the bugs?

Gardening Tip: Last Year’s Seeds

Coordinator’s Corner: Did it get cold enough to kill all the bugs?

Nate Walton, MSU Extension Master Gardener Coordinator

A winter crane fly (Diptera: Trichoceridae) active at 38°F on a day in December (2014).

It is common for people to wonder about the effects of very cold winter temperatures on all the little buggers that come out in summer to eat our precious plants or suck our precious blood. Unfortunately, despite the record cold temperatures that parts of the United States experienced a few weeks ago, most of our six and eight-legged friends were probably not adversely affected. Insects and other arthropods like spiders and ticks, have a variety of adaptations that allow them to survive winter. Some of these are behavioral, for example digging down into the subsoil to spend the winter where temperatures will stay above freezing all winter long. Others adaptations are chemical, they are able to produce compounds in their blood call Cryoprotectants or Ice Nucleating Proteins that prevent damage to their cells at sub-freezing temperatures.

Under certain conditions, these protections do fail, for example if the temperature drops very quickly in the fall or spring when they are not prepared. Another circumstance that can result in greater than normal insect mortality in the winter is if it gets very cold without an insulating layer of snow over the soil. This year we have been lucky (or unlucky) enough to have abundant snow cover in many places, so insects were protected from the extremely cold air temperatures that accompanied the polar vortex.

There are a couple of other ways that insects, ticks, and spiders can suffer mortality during the winter. For one, a very long winter can cause their fat reserves to become exhausted so that they starve to death before it warms enough in the spring for them to eat again. Finally, extremely cold and/or long winters drive warm blooded animals like mice and squirrels to eat more in order to stay warm. Insects are a great source of calories so their populations can suffer during cold winters, especially when rodent numbers are high.

If you didn’t already, I’m sure you’re now beginning to see why it can be very difficult to predict the effects of winter temperatures on pest insect populations. The bottom line is that fall and spring conditions are probably more important than winter cold temperatures in determining summer insect populations. Another thing that we can say for certain is that the effect of weather impacts the beneficial insects like our pollinators just as much as it does the pesky ones. The next time you are hoping that the polar vortex will kill all the mosquitoes, consider what it might be doing to the butterflies and bees as well!

 

Rattlesnake Master (Eryngium yuccifolium) at the Boardman River Nature Center February 5th 2019.

 

Gardening Tip: Last Year’s Seeds

by Cheryl A. Gross, AEMG

On our house, we never use all of the seeds in a packet in one season.  Will they germinate in year two? A way to test the “old” seeds is to use 2 sheets of paper towels, a plate, and 10-15 seeds.  Moisten the paper towels and sprinkle the seeds between the sheets. Keep moist, but not wet, for up to two weeks. Check the seeds for signs of germination.  Depending on the number of live seeds you can make your decision for planting. Should you see 50% germination, you can use the seed and seed heavier. Less than 50% you just might want to purchase fresh seed.

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