My orange and mandarin orange trees are having the leaves nibbled all over, especially the new growth. My question is can I use seven dust on them? I can never find the culprit(s) so I do not know what is getting to them. I search the plants and the underside of the leaves-NOTHING- I do not know what is chewing on them. Any advice out there?

Could it be slugs? check for the slime trails.

no idea what seven dust is... so I can say if its usable or not

jfredt69,
It sounds like your having the same problem as I. Little critters like grasshoppers,"june"bug beetles and various other chompers. You can use sevin dust on your trees with out harm.

This is the protocol I have been following and it appears to be working.
week 1) sprinkle 5 or 10% sevin on all the leaves and on the surface of the soil. Make sure you dust EVERY leaf.

week 2) same as above but use Permethrin. This is sold in my area as flower and garden insect killer dust by Eliminator.

week 3) Spray with liquid sevin in a pump sprayer making sure to cover all parts of the leaves and stems. Only spray in the cooler parts of the day and never in direct sun.

This is the protocol given to me by the nursery here.

The grasshoppers are very hard to kill as the chemical must actually contact them. They get the chemical when the hop onto the leaves to dine.

So far this is working as I have no more chewed leaves and actually have a lot of new growth thats not being eaten. This is a really bad year for these critters.
Andi

Thanks for the tip. I will be out there dusting this evening. They are not eating much like 1/3 of a leaf but it sure is irritating.

Your lucky. All I had left of the munched leaves was the center. This being the little stem like thing running down the middle of the leaf. My trees looked soooo sad. If you get any rain or the leaves get washed off in some way,you will have to reapply.

For those of you who don't know Sevin dust is Carbaryl( 1-Naphthalenol-methylcarbamate) mixed with a powder, usually talc. This is also the main ingredient in several otc brands of pet flea killer.

Thanks for explaining that for everyone and for correcting my spelling. I figured it out this week at lowes when I was buying some---