Zinnia pests

I had some really beautiful zinnias this summern and they bloomed prolifically, but by mid-summer the leaves were all flea-bitten, spotted, and ugly. What is it that does this, and what can one do about it?

Paullus, There are two problems that plague zinnias in our zone - Japanese beetles and mildew. Both can leave zinnias looking pretty ragged.

For the beetles, I spray with an insecticide (in the early morning before bees are out and early so that it will dry quickly ), usually Bayer multi-purpose which is needs to be reapplied weekly during peak JB time. To control mildew, I water early in the morning and avoid splaying water on the leaves. If you have a lot of rain, mildew may be unavoidable.

I have noticed that the zinnias planted in full sun with good air circulation had the least amount of problems with mildew.

Also, profusion zinnias did well for me planted in mass - with deadheading necessary only late in the season. And even with all the rain we had this summer, I didn't see any signs of mildew until recently. Nat

Paullus, one thing you might consider is a second planting later in the season. A few years ago I didn't get my zinnia seeds in the ground until the end of July and they were beautiful right until the frost killed them. Normally they would be looking so bad at the end of July I would be ready to pull them up and throw them away. So now I don't even bother to plant them until summer is almost over. That way I can put an early crop in that space and get double duty out of it.

I don't plant my zinnia seed until June. The plants seem to be stronger and I rarely have mildew problems. They bloom a bit later, but that's just in time to take over after daylilies slow down. I transplant my 24 inch zinnias between iris & daylilies when they are 6 inches tall.
The gardens are bright with zinnias now!

Come to think of it, I DO have a "zinnia pest"---is name is Walker (puppy) and his four legs are rough on zinnias, irises, daylilies & everything else in my backyard flowerbeds.