Ever wonder why yellow jackets seem so much more bothersome in the fall?

Maybe they think their days are numbered.

But there is a reason why they come after your Labor Day picnic foods and choose some foods over others.

The adult wasps feed primarily on items rich in sugars, such as fruits, flower nectar and tree sap.

Larvae in the nest feed on proteins such as insects and meats, like pieces of grilled hotdogs and burgers, brought back by the workers.

The adult workers pre-chew and condition the meat fed to the larvae. Larvae in return secrete a sugary material that the adults relish.

In the fall, with adult populations at their peak, the larvae can’t produce enough sweet stuff for the adults.

Also, the larvae in the nest start to decline as the colonies begin producing queens. Nectar from flowers becomes limited, so the other sources of sugar, such as your can of soda, become more attractive.

The foraging needs of the workers change from proteins to ripe, decaying fruits, and other sweets to keep them and the rest of the nest alive.

If they become too bothersome, slowly move away from the feeding frenzy, and quietly reclaim and cover the food.

Don’t swat them, as their venom contains a chemical attack message, which encourages others to arrive and can result in large numbers of unwanted aggressive yellow jackets.

Mosquitoes are another annoying pest. To prevent and control mosquitoes around your home, it is important to understand their life cycle.

Water is vital to mosquitoes. The mosquito egg, larva, and pupa all require water. Without water the mosquito cannot progress through its stages to the adult. Only the fourth stage, the adult mosquito, with which we are all familiar, is non-aquatic. Therefore, if stagnant water sources can be eliminated, mosquito breeding will be prevented, and adult populations will be reduced.

Here are some things that you can easily do to control mosquito populations:

Eliminate all standing or stagnant water by draining and filling depressions with soil.

Dispose of empty paint buckets, tin cans, old tires and other discarded containers.

Clean clogged roof gutters and drain flat roofs.

Change water in birdbaths and fountains at least weekly.

Empty small plastic swimming pools when they are not in regular use.

Drill holes in unused tires or tire swings to allow for water drainage.

Prevent saucers under plants from accumulating water. If larvae are seen, dump the water and refill.

Watch for any possible breeding spot and deal with it immediately.

Around your home, you can protect yourself by screening windows and doors and relocating outdoor lighting. A fine screen (14 to 18 wires to the inch) is the most satisfactory for excluding mosquitoes. Window and door screens should fit tightly, and doors should swing out and be self-closing.

Outside your home, wear protective clothing and apply an insect repellant, if desired, with strict adherence to the directions on the label.

Bug zappers, sometimes sold for mosquito control, are not effective for mosquito or biting fly management. On the contrary, they kill many desirable, beneficial insects.

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