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Over the Garden Fence

Good and bad trending insects: pollinators and bagworms

Show of hands, please. How many did something to mark National Pollinator Week? Back in 2007, the Senate approved and designated a week in June to draw attention to the decline in all kinds of pollinators, not just the pretty ones (few of us think of a bat or beetles as pollinators, but they do the job too.) Fast forward to 2020, and what we are hearing is the very same concerns with an increasing degree of alarm.

University of Illinois Extension Horticulture Educator Ken Johnson out of Jacksonville, Ill., put together some compelling facts, activities and cultural changes on how we maintain our home landscapes that could really make a difference with our pollinator populations.

First off, without pollinators we would not have many of our favorite fruits and vegetables. There would be no apple cider each fall since nearly all apples have to be cross pollenated by pollenating insects. Some other favorites include watermelon, cucumber, squash, and don’t forget pumpkins! Johnson’s list goes on with other fruits, vegetables and flowering plants. By the way, there is a region in China were pollinators are gone, and pear trees must be pollenated by hand.

As you expand a flower bed, think diversity (more varieties) and depth. By depth, I mean plan the flower garden so there is more than just one kind of flower attracting a given insect. Be sure there will be something else in bloom the next week and the weeks following to attract insects back. Insects need to eat throughout the season. For plant ideas, check out this guide from the Pollinator Conservation Resource Center or find a resource list from Illinois Extension of Cook County.

One of Johnson’s last points on maintaining our pollinator-friendly landscapes is one that goes against what we have been culturally engrained with for decades. Weeds are OK. It is OK to have some in the flower beds and lawn. Those weeds actually can provide a source of energy when nothing else is available for pollinators. This is certainly a different mindset from how many of us grew up or were taught, but not the case further in the past. Prior to the introduction of phenoxy herbicides for dandelion control, lawn seed mixes used to routinely contain clover and we are now beginning to embrace that again.

Another trending insect right now is the bagworm – the only bug that comes to mind that carries around its “mobile home.” While young, the larval stage moves about the plant, eating and enlarging the bag while adding decoration of plant parts to the outside. They will feed on deciduous and evergreen plants so their mobile home can look quite different. By late summer, feeding has stopped and the bag is permanently attached to the host plant. Another twist is males and females overwinter in separate homes. The female has her offspring inside by way of 300 to 800 eggs. These hatch the following spring to carry on the generations.

They are trending now because usually these hundreds of offspring are out there feeding right now. They can total defoliate an entire tree, as there can be hundreds on one evergreen or deciduous tree. The best control window is while they are feeding, as soon after hatching as possible. Once inside their “bag of fortitude” they are untouchable. Fortunately, they are controlled by one of the BT products (Bacillius thuringiensis kurstaki) considered environmentally safe.

About the author: Richard Hentschel’s expertise extends across several subject areas with specialties in lawn care, fruit tree production, woody ornamentals, and home and community gardening. During his 45-year career in horticulture and agriculture, Hentschel became a well-known and respected expert for commercial and homeowner audiences, industry organizations, and media. He retired from University of Illinois Extension in April 2022 with nearly 30 years of service as a Horticulture Specialist and Educator in northern Illinois.