Spotted This Large Green Caterpillar Covered in White Things — Is It Fungus or Eggs? Should You Remove It?
Finding parasitoid cocoons can actually be a positive sign.
It means that natural biological control is occurring.
Your garden has organisms capable of finding and attacking pest insects without you having to introduce them manually.
That’s valuable.
A garden with flowering plants, diverse vegetation, and fewer unnecessary pesticide applications can provide better conditions for beneficial insects.
Adult parasitoid wasps often need nectar or other food sources, so flowering plants can help support them.
A Simple Rule to Remember
When you see a large caterpillar covered in dozens of small white, rice-like cocoons:
Don’t panic.
Don’t assume they’re eggs.
Don’t immediately spray it.
Don’t remove the cocoons.
Instead, recognize that you may be witnessing one of nature’s most fascinating forms of pest control.
The caterpillar has essentially become a nursery for parasitoid wasps.
Frequently Asked Questions
Are the white things eggs?
Usually not in this situation. The rice-like structures shown on the caterpillar are most consistent with parasitoid wasp cocoons, especially braconid wasps associated with hornworms.
Is it a fungus?
The photograph is much more consistent with parasitoid cocoons than fungal growth.
Should I kill the caterpillar?
If it is covered with these white cocoons, extension recommendations generally say to leave it alone so the adult parasitoid wasps can emerge.
Will the caterpillar survive?
Usually not. Once the parasitoid larvae have emerged and formed cocoons, the host caterpillar generally dies.
Are the tiny wasps useful?
Yes. Parasitoid wasps can attack other caterpillars and contribute to natural pest control.
Should I spray insecticide?
Not on a caterpillar already carrying parasitoid cocoons. Doing so can kill the developing beneficial wasps and interfere with natural biological control.
Final Takeaway
That strange-looking caterpillar in the photograph isn’t simply covered in eggs or suffering from an obvious fungal infection.
The white, rice-like structures are most likely parasitoid wasp cocoons.
The wasp larvae developed inside the caterpillar, emerged through its body, and created the white cocoons on its exterior. Eventually, adult wasps will emerge and can search for other caterpillars to parasitize.
So if you discover this in your garden, leaving the parasitized caterpillar alone is generally the best choice.
What looks like a strange or disturbing insect infestation may actually be one of the garden’s natural defense mechanisms.
Nature has its own pest-control system—and sometimes, it looks like a caterpillar covered in tiny grains of white rice.
