Whats eating these leaves?

[Janetrob 0]

Hello! I am new to this forum so thank you in advance! My own garden shrank greatly when I moved to a condo 4 years ago so I get my gardening fix by helping friends and volunteering here and there. In a  friends garden in Royal Oak, many of the leaves now emerging in some plants are being chewed. The plants they are eating are Mullein and mint; they avoid Queen Anne's lace and sage. It started a week or two ago. Insecticidal soap is doing nothing. My friend has looked closely and at various times of day and sees no evidence of bugs. I am wondering if it could be rabbits or other small animals. Appreciate any thoughts

 

[admin 1]

The pattern of damage is definitely not rabbit and almost certainly not bird: damage areas too tiny for rabbit chewing, not ragged/torn enough for collateral damage birds cause when stabbing to reach insects. It looks much more like a caterpillar, something that sat ON the leaf and moved its head back and forth in an arc eating leaf tissue edge-inward. Not a slug, they eat within the blade, not edge-in. Not a beetle, they scrape. Maybe a weevil but there are bigger areas of leaf involved than usual and this is not within usual weevil-season. Not a bug or aphid, they pierce, suck and deform or scar where they fed.Maybe a sawfly but like weevil issue, scope of each eaten area is bigger than is usual for sawflies, plus sawflies generally eat an entire leaf before moving to another. So I would look for caterpillars hiding nearby. You do that and I will go check our moth and caterpillar host plants lists to see if I can find any leads there.

[Janet Macunovich 32]

Oops, sorry that was me up above. Forgot I was in administrator mode.

I forgot about earwigs. Seems early for that but could be, and you'd find them feeding in low light/night.

As for caterpillars there is a mullein moth but timing is wrong. There is a petty gray hairstreak but seems early there, too. plus we may be looking for one insect that feeds across these two plant famous so perhaps the skinny pale green, pretends-to-be-a-twig-when-scared Crocus geometer moth caterpillar which does emerge in spring from winter as a nearly full grown caterpillar and so could eat big.

[Janetrob 0]

Thank you Janet for your speedy reply! I will let her know and we will look for caterpillars. Is there a way to keep them away thats not toxic or harmful? (aside from picking them off which doesn't work well when you can't see them!)

[Janet Macunovich 32]

No non-toxic answer to caterpillars, not if you're the caterpillar. There are insecticides that will kill the caterpillars that won't hurt much else than caterpillars - look for insecticides with active ingredient Bt, bacillus thuringensis. It's a bacteria that sickens a caterpillar to death when it ingests it. Tough to even think that now as humankind battles a virus we seem to have no immunity to, that we are the ones who look for such things to loose on other life forms!

 

This may help, though. if it is a caterpillar at work, it is almost certainly a limited run of feeding. It will turn into a butterfly or moth and then your plants can re-grow. There are some caterpillars, some species, that have so many generations each year that the feeding damage is nearly non-stop. But far more of them eat a while and then are done.

 

For instance we just noticed day before yesterday that the American lady caterpillars are here eating the pussytoes - yay! We like this orange-plus butterfly and she needs our help. The ONLY plants her caterpillars can eat are native pussy toes (Antennaria species), pearly everlasting (Anaphalis maragaritacea, another native) ,edelweiss and maybe one ocean-barrier-isalnd artemisia. So we plant pusy toes and pearly everlasting jst for this butterfly.

 

The caterpllars will eat away and make a mess of the plants' growing tips but then they will crawl off, form chrysalises and emerge as American ladies to add their mature color to our garden.

 

No non-toxic answer to caterpillars, not if you're the caterpillar. There are insecticides that will kill the caterpillars that won't hurt much else than caterpillars - look for insecticides with active ingredient Bt, bacillus thuringiensis. It's a bacteria that sickens a caterpillar to death when it ingests it. Tough to even think that now as humankind battles a virus we seem to have no immunity to, that we are the ones who look for such things to loose on other life forms!

 

This may help, though. if it is a caterpillar at work, it is almost certainly a limited run of feeding. It will turn into a butterfly or moth and then your plants can re-grow. There are some caterpillars, some species, that have so many generations each year that the feeding damage is nearly non-stop. But far more of them eat a while and then are done.

 

For instance we just noticed day before yesterday that the American lady caterpillars are here eating the pussytoes - yay! We like this orange-plus butterfly and she needs our help. The ONLY plants her caterpillars can eat are native pussy toes (Antennaria species), pearly everlasting (Anaphalis margaritacea, another native) ,edelweiss and maybe one ocean-barrier-island Artemisia. So we plant pussy toes and pearly everlasting just for this butterfly.

 

The caterpillars will eat away and make a mess of the plants' growing tips but then they will crawl off, form chrysalises and emerge as American ladies to add their mature color to our garden.

 

Do go out with a flashlight at night and look at those chomped plants. If it happens to be earwigs, it is it is a nighttime thing.

 

I am very glad you asked about this and with apologies for getting way off onto caterpillars, I am going to include the following and more on our Garden A to Z newsletter this week so others who grow these plants can also grow these butterflies!

 

Got to look close before and as pussytoes comes up to bloom, to notice some of the leaf tips are knit together:

 

 

By the time the plants are going to seed the caterpillars are nearly full grown and ready to quit eating: