Jim Hoelsworth, franchisee from Vineland, NJ, recently sent in a picture of an upright yew covered with some sort of webbing. What he is seeing is the mass hatching of spiders, producing long strands of silk that catch in the wind to disperse them to another location. This process is called “ballooning” and it enables them to float long distances.
Spiders will hatch in both spring and fall in large numbers, but fall is the time when most spiders hatch. When the hatching of one species occurs on a windy day, their “balloons” blow into each other and become entangled with each other into a large mass, as what you see in this picture.
Spider ballooning passes in a couple of days and the excess spiders will eat each other and it will be over. The webbing can be washed off the shrubs with a strong stream of water. There is no real reason to spray an insect control product as the new spiders do a good job controlling their own population.
The first time I saw ballooning spiders was in the early 1980s when I was called to a customer’s home because there were spider webs all over the front of the their home. I thought they were exaggerating until I pulled up to see an amazing site. The front of their house was nearly covered in spider webs and so was their car in the driveway. It was like a scene out of the Twilight Zone. I really did not know what to recommend, but I remember that I did not see any spiders crawling over the webbing. I told the customer to sweep off the webbing and that should take care of it. I was able to learn the story behind spider ballooning from someone at the University of Illinois Extension Service.
Unfortunately, this was before digital cameras or cell phones, so you will just have to take my word that I did see this weird phenomenon and it was a creepy site.