Whenever we have a mild winter folks complain that mosquitoes and other insect pests will be worse. This past January we had some of the coldest temperatures in several years. People have asked me if that weather might have a silver lining. It’s wishful thinking.
Think about it. I’m originally from Maine where the mercury plummets far more than it does here. Mosquitoes are worse too. I’ve heard they are especially bad in Alaska also, and it’s much colder there. Standing water is the key to high mosquito populations, so if we have a wet spring we can expect more of the ravenous blood sucking devils. If it’s dry in April and May, we might have fewer.
I hate to be a wet blanket, but the same goes for most crop pests. Spring weather influences pest populations much more than winter weather does. Even without the protection of a few feet of snow, frigid temperatures in our area have virtually no effect on crop pests either. Don’t expect the near zero temperatures to deminish the corn borers in your garden this summer.
Long-term cool temperatures have a greater impact. All arthropods are what we commonly call “cold blooded.” Their body temperature depends on their environment. If it’s warm they are active. Cool temperatures cause them to be lethargic. If it were to be cool during March, April and May, many pests would not reproduce at the same rates they normally do. Cold temperatures would certainly create other problems, however.
Moisture is far more important to bug populations than temperature, particularly past temperatures. Many insects overwinter in soil. Dry conditions are generally not suited for their survival.
Too much water will benefit mosquitoes, but it will harm populations of other insects. Ants and other things that basically live underground would be negatively impacted.
Temperature has little to do with diseases that harm plants either. Controlling plant pests is more effective with proper culture and sanitation. Many diseases are made worse because infected tissue remains in the field and the same crop is planted the following spring.
For a disease to manifest itself three factors must be present. Without a susceptible host, a virulent pathogen and a favorable environment a disease could not occur. However, removing all plant residue is usually unnecessary.
Cover crops can cause what I refer to as a microflora civil war. Different microorganisms compete for resources and often the beneficial ones outcompete the pathogenic ones. It doesn’t always work in some agricultural situations, but that’s basically how nature works.
On the positive side, bees and other beneficial insects shouldn’t be bothered by this winter either. Both predators like lady beetles and praying mantis along with parasites like many wasps should be out there killing the bad guys. Pollinators should be doing their thing too.
Since we’re disposing of myths, woolly worms don’t forecast coming temperatures. They’re an indication of what’s already happened. The more they have molted, the browner they become. Different species also have different patterns. Some naturally are more brown while others are more black. Direction of travel is a myth too. Northward crawling caterpillars do not forecast a mild winter. Sorry.
Ted Manzer teaches agriculture at Northeastern High School (firstname.lastname@example.org).