Wasps in fall

Every year when fall creeps in around the garden, harvest is at its peak.  But not all who glean the garden are popping things into freezers or canning jars.

Some are taking it back to the queen, where she waits, grumpy from heat and exhausted from a summer spent laying eggs, surrounded by a court less tolerant and quicker to anger.  Yes, fall is the season when wasps make their presence known, and this year is no exception.

A simple explanation is that yellow jackets are more noticeable in fall because there are more of them.  Each winter only fertilized queens survive, hiding in nooks or crannies of the landscape, while abandoned nests wither and die.  In spring young queens emerge to start a new colony.

Although adults prefer a high carbohydrate diet of fruit or nectar, the larvae like meat.  This the adults scavenge, bringing back insects, earthworms, or chunks of the hamburger they raided from your picnic.  Once at the nest, the adults lovingly chew the food to make life easier for the young, something any parent can relate to when thinking of the lengths they go to just to get their kids to eat.

In return the parents are treated to a sweet material produced by the young as a thank you.  Over the summer this arraignment works – the adults feed the young, and the young feed the adults.  But in fall, the queen lays fewer eggs, resulting in fewer young.  This puts the colony on a diet and, ravenous for sugar, the adults aggressively work our yards, searching for any and all sweets.

By the time we notice that wasps are a problem, the colony has grown to huge proportions, easily housing 200 or more tightly wound, half-starved, heavily armed denizens who want sugar and want it now.

Picnics, fruit trees and garbage attract notice; an open soda becomes a mob scene.  Their rage at being thwarted in a sugar fix is a lot like the reaction to someone trying to cut in line at the Starbucks at 7:30 a.m. – extreme, with repeated stinging to drive off those who get in the way. 

Nothing is safe from their wrath in fall, and if you’re unlucky enough to be allergic to their venom, you need a plan to get rid of these insects.  Normally, when it comes to human-insect interaction, I counsel understanding.

Forget that.

 These bugs are a problem, and the best way to fix it is to find the nest and destroy it.  This is not an easy feat:  yellow jackets are a ground dwelling wasp, making it difficult to find them.  Once you have, destroying it isn’t easy – very often the colony lives quite a ways from the entrance, and sprays may not reach them.

Lure them to a trap baited with heptyl butyrate, which is similar to sugar water.  These brightly colored plastic tubes entice yellow jackets, but not honey bees, with the sweet drink they crave.  But place it away from spots where you picnic – no point in reliving that Starbucks incident.

If there are a lot of wasps flying around a tree, check the leaves and young shoots for honeydew producing insects, such as aphids or scale.  The honeydew – sugary waste excreted by sap-sucking bugs – is what the wasps are after, which shows you the horrors of a sugar addiction gone wild. 

A strong jet of water will knock aphids off of the leaves, but if the tree is heavily infested with scale a stronger approach is needed, such as applications of dormant oil during winter.