Spotted lanternflies, brown marmorated stink bugs, boxelder bugs, mosquitoes, flies.

When will they be hatching or coming out of dormancy?

Will the 2019-2020 winter of warm temperatures in the Lehigh Valley increase insect populations in the spring?

Winters of extremely cold temperatures also influence insect populations for a following spring and summer.

The answer to both questions may surprise you.

Winter weather has little influence on insect populations for the following spring. This does not mean that winter temperatures do not play a role.

Many assume a warmer winter would increase insect populations. If anything, warmer winters and extremely cold winters will both produce lower insect populations at the beginning of spring.

The reason winter weather has little influence on insect populations is because insects have developed excellent defenses to survive.

Many insect species survive over the winter in different life stages.

Spotted lanternfly adults lay eggs in the fall and the young hatch in the spring.

The pupae (cocoon) may stay during the winter months with an adult emerging in the spring.

With other insect species, adults may stay dormant during the winter and become active with warmer weather.

All insects have processes to survive the winter. An egg, a larva, a pupae or adult of any given insect will generally wait in a protected location until warmer weather arrives. These locations could be tree bark, rocks, logs or houses.

Fluctuating temperatures during winter can have major effects on insect populations.

If there is unusually warm weather during February and March, it may confuse the overwintering insects. The warmer weather may mistakenly trigger them to emerge from their protected location. If there’s a period of freezing temperatures, the exposed insects may die.

If there’s an early spring and warm weather stays constant, insects will begin to emerge. An early spring may give the insect a longer period of reproduction creating higher populations by late summer.

Conventional wisdom might conclude that extreme cold winters might reduce certain insect populations.

Cold weather can also kill predators and pathogens that keep certain insect populations in check. A warmer winter may allow these factors to keep a particular insect species at bay.

Wait and see what will happen this spring.

Spotted lanternfly: After the warm winter weather, when will the spotted lanternfly emerge from its egg masses? Nymphs are small (1/8 to 1/2 in.) and can be hard to find.

The first three instars are black with white spots. Typically, the first instar will emerge May to June.

With warm winter, it might be best to be on the lookout for them in late April.

Go to https://extension.psu.edu/spotted-lanternfly or call 1-888-4BADFLY for up-to-date and comprehensive information about the spotted lanternfly and how to manage them.

“Growing Green” is contributed by Lehigh County Extension Office Staff and Master Gardeners. Information: Lehigh County Extension Office, 610-391-9840; Northampton County Extension Office, 610-813-6613.