Hornet Nest dangers
I have a hornet's nest in my front yard the nest is approximately 10 ft. above ground level in a tree. The tree is less than 10 ft. from the walk to our front door. Should I be concerned about visitors agitating them on their arrival? Should I be concerned about cutting the grass directly below it?
New Castle County Delaware hornets
Hornets largely prey on other insects and play an important role in keeping the pest population in check; however, many people are allergic to the venom of these insects (Hundreds die each year from allergic reactions). In your case I would consider removing or having the nest removed as it is close to people traffic.
With nest being in a tree I would expect it to look like an inverted tear-drop ball. These nests start out small with the queen laying eggs and as they hatch the workers enlarge the nest and it can end up being larger than a basketball.
You can have a professional exterminator take care of the job for you or if you are diligent and agile you can do the job yourself.
First of all don't attempt this if you are allergic to insect stings it is not worth he chance.
There are hornet sprays (JET spray) which are sold at big box, hardware and garden centers that shoot a spray about 20 feet.
You should do your spraying about 2hours after dark when most of the hornets are in the next.
First make sure you have a plan of escape in case you require it. Put on a long sleeve heavy shirt closing up the cuffs and neck. Use a flashlight (preferable one with a red lens, Hornets can't see red light well) Test out the spray can operation then continuously spray the bottom opening of the nest. Don't get so close that the pressure from the spray disintegrates the nest as that will have a larger opening for the hornets to escape. Spray the opening and you will see many hornets drop. Retreat to an inside location when you are done and check the site the next day. Also remove yourself from the area if you feel threatened. You may have to repeat the operation on another night if the nest is large
A good detailed reference is 'Controlling Wasps, Bees & Hornets Around Your Home' from Univ of New Hampshire Cooperative Extension.
Consider the exterminator and be carefule