Collateral Damage

The leaves are starting to fall, many of them stressed by the hot temperatures and lack of rain in September this year. I’m not sure that it will be a very colorful fall in my area. As the leaves fall down, so very many of them, I am reminded of this post that I wrote about 5 years ago on another site about being tolerant of insect herbivores (those that eat leaves).

Chewed Franklinia leaves

Things have to eat to survive. When plants are eaten, they don’t always look as good as before they were eaten. Think of a head of leaf lettuce growing in your garden. It is so beautiful there - wavy leaf margins and a blush of burgundy at the tips - until you lop it off to harvest it for your dinner. You weren’t really thinking about how the plant would look after that, were you?

Plants eaten by caterpillars sometimes lose their good looks too. Caterpillars don’t go into the endeavor to make the plant look bad. That’s just collateral damage, a consequence of getting the nutrition they need to reach adulthood and become a beautiful moth or butterfly.


Leaf damage comes in various forms:

• Some caterpillars eat entire leaves; the spicebush swallowtail in my yard modestly consumed one leaf each night, leaving no trace whatsoever of what had been consumed.
• Some caterpillars eat holes in the leaves or just the edges of them, leaving a patchwork of damaged leaves.
• Some caterpillars skeletonize the leaves, leaving a lacy reminder of what was there.
• Others, like fall webworms, smother the branch tips in a tangled web of silk, turning all the leaves to a crispy, brown mess.

An oak sapling with the top growth eaten by caterpillars

For the most part, only a fraction of the plant is affected by caterpillars. The larger the plant, the less noticeable the damage is. A large oak tree, for example, may have damage only on the branches high in the tree. A milkweed perennial, on the other hand, may lose a lot more. Yet both of them are doing exactly the same thing: supporting the larval form of a moth or butterfly.

Sourwood growing new leaves
after caterpillars ate it

After the caterpillar is finished growing up, many plants will sprout new leaves to replace the ones that were eaten. Nature has a way of dealing with the situation. Plants have been living with bugs that eat them for thousands of years.

Are a few chewed leaves so bad? If the infestation seems unbearable, don’t reach for the pesticides. You can pluck some off by hand (wear gloves if they bother you). Another alternative: blast them with a spray from the hose. Some may come back to the plant, but others will get eaten by predators that might not have reached them otherwise (frogs, toads, lizards). Rest assured that when you are not looking, hungry birds will be helping you out by snatching a few.

Everything has to eat and, no matter how many we think they eat, there are always plenty to fall down in the fall. Allowing caterpillars the freedom to eat leaves in our garden demonstrates our willingness to share the table we call Earth.