Pest Control/Tan flat


After disturbed
After disturbed  
Tan bug mark?
Tan bug mark?  
QUESTION: It seems like (more so after a rain) I get these "sandy" flat tan "marks" on the inside roof of my patio.  Now they are all over my grill cover.  (see attached photos).  Sadly I wiped away most of them before I thought to take a photo. But there must have been 20 different "marks".

These "marks" are easy to wipe off, and look like sand when wiping (photo attached.  It's a brand new white patio roof so imagine my dismay when I walk out to show someone and there's these tan "skid marks" all over it.

I also saw in the same area, a cluster of teeny black bugs - I believe from reading earlier posts these may be sprintails.  I don't have photos of these. I don't know if the two are related.

Thank you for your time!

ANSWER: Laura,

I think these are moth eggs but I'm not 100% certain. Moths often lay their eggs in clumps on flat surfaces. If you have outdoor lighting in this area it may be attracting moths at night. This is not related to springtails (see for more about springtails). My guess is that this egg laying is unusual and won't occur again but consider reducing outdoor lighting at night.

Jack DeAngelis

---------- FOLLOW-UP ----------

QUESTION: several "friends" are saying these are dirt dobber nest beginnings. . i hope the heck not since there is about 30 of them,  including the grill cover. eeeek!

ANSWER: I considered that as well but rejected the idea because the marks are so irregular, mud daubber nests are more symmetrical.

Jack DeAngelis

---------- FOLLOW-UP ----------

QUESTION: you are an expert!!! while searching Et photos of moth egg cases I found a pic of a cluster of tiny black bugs.. what I saw wasn't springtails.. they were hatched moth babies...

i also saw photos of moth egg cases on tired,  which look exactly like what's on my grill cover. .

thank you!  so you say having 20 to 30 egg cases in one area is rare I hope? ? thank you so much!!

Who knows? But, moths prefer to lay their eggs on their host plants. It is possible that this year the moths that laid these eggs and their host plants were "out of sync" so that the plants were not available when the moths needed to lay their eggs, perhaps unusual weather.

Jack DeAngelis

Pest Control

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Jack DeAngelis


I can answer questions about the control of pest insects, spiders, mites and related arthropods. These household pests include termites, carpenter ants, powderpost beetles, nuisance ants, bed bugs, cockroaches, fleas, wasps, and many others. I can also answer questions about using pesticides and other pest control tools such as baits and traps.


I am a retired university extension entomologist. I've taught and conducted research in urban and agricultural entomology. I've published over 70 extension publications, 20 research publications and several books about insects.

Ph.D. in Entomology

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