White stuff on milkweed leaves

[TypingMonkey]

I have this white stuff that looks like dust on the milkweed leaves. I can't rub it off. Does anyone know what this is and if it's bad for the plant. If it's bad how do you stop it without hurting the caterpillars.

Also, I don't know if this is relevant, but I noticed spider webbing sometimes under the leaves. When I see this I just take it out and I do manual removal of aphids everyday.

[Mona Miller]

Yes, definitely remove spider webbing. Some of them contain small or large spiders. The white stuff many be a fungus. Don't feed leaves that have fungus to caterpillars. Water from the bottom, not the top if possible. Also, wash and dry the milkweed that you are feeding your caterpillars--that will help gets some of the small insects off.

I'm having to do the same thing in my yard. Squishing, washing off, squishing.... I used Ladybugs before the Monarchs came. I don't recommend ladybugs when the Monarchs are laying. Ladybugs will eat Monarch eggs, too.

http://www.mymonarchguide.com/2007/08/m ... blems.html
Milkweed leaf 'problems'