No Dahlias For Me - Spider Mite Infestation

All my dahlias were full of buds, everything was looking like it was going to explode into bloom any time. Had a family emergency. When I was finally home & able to tend to my garden, found several
of my dahlias covered with fine spiderwebs. (Not just my dahlias, most every flowering plant I have but looks like it started with the dahlias). Learned fast what spidermites are :( Both Park Princess, several Dahlietta Margaret, two big pink and one large white noid dahlias were beyond hope. I still have Delicious Marshmallow and a white noid dahlia that hadn't gotten to the web stage yet, so hoping those will be able to recover. Blanket flower & all but one marigold plant were beyond salvaging. Daisy is still iffy. Everything else looks like it should recover. Funny thing, though, the spidermites left all the purple coneflower alone!

Dahlia experts, do you routinely spray your dahlias for bugs BEFORE you ever see any pests on them? Except for something munching on one of my flowering dahlia's petals last year, I've not had a problem with pests in the flower bed.

Spider mites are an expectation for me. I can never see the little pests, but I know they're there as they string those webs on my 8 ft stakes, even before the plants come up. They are completely out of control since the DDT in the 70s had removed most of the natural predator mites. In the past I have been spritzing the dahlias with water from a hose at least once a week Around September its sometimes twice a week, as the population would typically peak then. Water spritzing can be very effective and inexpensive, it shocks and kills them and destroys most of the eggs. They cannot adapt to that like with the pesticides. It takes them about 3 weeks to become immune to one pesticide, so you would have to rotate pesticides, water is better IMO.

This year however I shelled out for 5000 predator mites (yes you can buy bugs), that's for about 1100 sq. feet of space though. It takes me too long to spritz so many plants.

Water alone will kill spider mites & destroy their eggs? Very good to know! Do you spritz your dahlias at a specific time of day? Thinking morning would be preferable to evening, to give the plants a chance to dry? I was just horrified to find those webs on my flowers,
and to find that some of the plants were damaged enough that they couldn't be saved.

My flower bed is pretty small, so won't be too much work to keep the spider mites under control - I hope! Appreciate the tip about it only taking about 3 weeks for them to become immune to one pesticide and needing to rotate pesticides. We've already sprayed everything with a pesticide, but will switch to using water spraying, I'd prefer not to use
a pesticide unless I really have to.

Thanks!

Good luck, Jolie. Please follow Tod's advice with the water. It works.

I'd spray in the morning, if possible.

Thanks, Pirl. As of this morning all but one of the plants don't look any worse than they
did yesterday, so I'm hopeful these will survive the damage.

Good luck JolieB and you go Todd with the mighty predator mites. My predatory mites are bright orange and they ROCK.

Aww, sorry Jolie-that stinks. That happened to me last year, so this time I vowed to standby with a hose and pesticides to prevent them. It only takes a day or two to go from a tiny bit to a whole plant (or more) infestation, down here anyway. Wiped out almost all my plants last year. Once a week, I try to check most undersides of leaves on all the plants. Sounds ridiculous, but I just do it when I weed, prune, water, etc. I may not do the whole garden in one day, but I'll check one half or 1/3 one day, the rest next day, etc. I have had mini infestations this year, but I sprayed them and they came back, so stay positive, you might get blooms yet. May the force be with you!

A flower has bloomed on Dahlia Delicious Marshmallow! Nowhere near the bushy little plant it was before the spider mite
infestation, but finally have a flower and I've spotted a couple of barely-there buds forming. Looks like it survived and will thrive again. Whew!!

This message was edited Aug 3, 2010 8:47 PM

WHOO HOO JolieB. Wonderous news ^_^

D'nut said it best! Hurray for JolieB!