what is the powder???

the future is all in the terminal buds in the center... if that is viable.. in a few weeks you will know .....the powder.. is not going to heal the already insulted leaves ...

scratch around in the first inch of soil.. and see what you can find.. i would be looking for a cutworm within 8 inches of the plant...

the critter may be regional.. where are you ...

ken

ps: slugs are also an option ... but they arent insects.. so your powder would be useless ... but the bottom line is.. they feed at night.. get out the flashlight.. and go hunting as late as possible ....

Here is a link that might be useful: here is the beast ... now add the word DAMAGE and you will find some pix with the same type of damage ...

Looks like damage from slugs or snails, as Ken says, nocturnal (nighttime) critters.
Before putting out any pest control product, organic or not you should properly identify what you have so you are not putting the wrong thing out there and are not using the poison in the wrong way.

yep looks like slugs or catipillars,i tried that powderd pest control with little luck on tomatoes,didnt work at all for whitefly.every garden gets slugs and catipillars.you will have to check plants maybe of a night to find out exactly what is eating your plants,keep checking you will eventually find something.