Help! Bites on leaf edges, droppings? on leaves, no pests in sight

[Moranjl]

Hi orchid family. I’ve been very casually keeping orchids for a few years. Never encountered this.

There are “bites” along the edges of my phals and small brown droppings(?) on the leaves. I immediately inspected for insects, but there are none to be seen with the naked eye. Any thoughts?!?!

Thank you!

[SouthPark]

Maybe caterpillars? Do you have carbaryl?

[Ray]

Caterpillars, grasshoppers, roaches...

[Roberta]

Remember, caterpillars aren't affected by insecticides... spray with BT (Bacillus thuringiensis)... same stuff prescribed for tomato hornworms. Harmless to humans but kills larvae by starving them.

[SouthPark]

I think carbaryl is primarily used as an insecticide, but I also think that when the carbaryl is on the leaf etc, and if a caterpillar comes along to eat --- then something bad will happen to the caterpillar. But very unfortunately, carbaryl is not good for bees too.

But once again - the caterpillar etc is just doing their own natural thing to survive ----- but we have to protect our orchid ---- especially if their activity continues toward wiping out the whole orchid. An alternative that's bee safe will certainly be nice.

Thanks for the recommendation about BT Roberta. I'll head out to get some to add to my kit. Fortunately I don't get things chewing on my orchids much - quite rare. But better to be prepared in advance, that's for sure!

[Moranjl]

Hey folks. Thanks for insights. These are being kept indoors and I’m in a northern climate. Wouldn’t I see the caterpillars if they were there? I can’t kill what I can’t see

[Roberta]

Hmmm... caterpillars do hide. Mice maybe??? Others on the Board have more experience with those than I have.

[SouthPark]

It may well be mice, as Roberta mentioned.

One way to find out is to place a night/day (water resistant) digital video camera there - a relatively inexpensive one - aimed right at the leaf ------ and the camera should be able to reveal eventually what it is that is eating the leaves - after scanning through the recorded footage.

Originally Posted by Moranjl

These are being kept indoors and I’m in a northern climate. Wouldn’t I see the caterpillars if they were there? I can’t kill what I can’t see

That is true! The key piece of information is 'indoors', which we didn't have before. So with more information can come relevant solution suggestions.

Now ----- those pieces of debris on the leaves. They may be linked to this case. So need to look into that as well. But a video camera will definitely sort it out.