Dealing with thrips

Flowernut

Has anyone dealt with thrips using an organic approach? Last year I noticed a problem and I would like to eliminate the issue before I start selling bouquets this year.

SteveM

Flowernut Has anyone dealt with thrips using an organic approach?

Here, there are certain times of the year when thrips control is like chasing windmills. From mid-June to mid-July most of the weeds and grasses that surround my field die and their thrips population moves on - to my dahlia blooms. If this is a problem where you are at, then thrips control should probably start at the source. It might help to release the beneficials early, especially on the infested weeds and grasses that are on the upwind side of your dahlia plot. (thrips aren't great fliers but they are good at drifting with the wind)
In a month the mustard weeds will die an direct their Western Flower Thrips to my dahlias, which will be in full bloom:

Krista

I order these from Sound Horticulture: Orius insidiosus - Minute Pirate Bug and have been very pleased with the results.

This year, I’m growing Black Pearl Peppers in the hopes of hosting a breeding environment for them to prevent having to continue to reorder through out the season. It’ll be cool if the peppers attract local good bugs, but not sure that’ll happen. I’ll update on how this goes!

JessieC

Krista I’ll be interested to hear how your pepper experiment goes Krista! I’ve heard about them, but never knew where to find the plants or seeds. Good luck!!

Juliarugula

I’m a fan of minute pirate bugs too. They’re the only beneficial I’ve added to my garden that stuck around all season!

JessieC

Juliarugula I may want to give these a try. Thrips are such a downer! I’m guessing I’d want to find a supplier closer to Virginia, correct? Any other tips for using them? Last year it was too hot to spray for much of the season, and this seems like a better solution anyway. It’s a good thing to plan out now, while there’s not much to do other than wait for the tubers to sprout. (Kidding. There are a million things to do in the garden these days!)
Thanks!

Juliarugula

JessieC I ordered my minute pirate bugs from arbico. I actually think I just saw one yesterday but didn’t know they might overwinter? It could have been some other tiny black bug though…

Krista

JessieC this is what I ordered: Black Pearl Ornamental Pepper Seeds

ksc

The western flower thrips arrive here towards the end of June just as the first dahlia blooms appear. I treat at first signs with Tristar which also controls the Asiatic/Japanese beetles that show up about the same time. Soon after the natural population of pirate bugs take over and I don't need to treat for the rest of the year. I've also read that the western flower thrip feeds on mites too, There is another thrip that shows up in July which I believe is a predator, they are fast and I've never been able to collect one intact to make a positive id. If you zoom in on this you can see about 10 thrips...

JessieC

ksc May I ask where you’re located? I’m in Central VA 7b. I think they showed up in June last year. I’m better at spotting the damage than the thrips, but they sure do make the early part of the season ugly.
And do you have pirate bugs by chance, rather than having to add them?
Thanks!

ksc

We are in 6b about 25 miles south of Boston. I shake a bloom into my hand and can see the thrips moving. Or you can whack the bloom onto a piece of paper and you should see them moving. Our pirate bugs are native and show up in July.

drewtheflorist

Timing for beneficials is important ---if you don't have any of the bad critters for them to eat, they move on.

Krista

drewtheflorist Unless you have an alternative food source in place!

SteveM

6 weeks later...
As expected, but not appreciated, the thrips are feasting this time of year and control is difficult without spraying every few days. I can kill all of the thrips today and more will be back tomorrow so I just do minimal sprays and expect some lost sales as part of doing business. The white, yellow, and lavender blooms attract the most thrips but the dark colors show damage the most.

Bad thrips damage on River's Dark Chocolate:

JessieC

SteveM Sorry for that damage Steve! But your image is helpful. I never know what I’m looking for with thrips. The white blooms look dirty, which I think is thrips damage. Honestly, I still am not 100% sure what a thrip looks like!
Either way, it’s been too hot to spray here. I managed to spray twice before the heat came. Last year was the same—either rain or heat kept me from a proper preventative schedule. Sounds like it might not matter a whole lot with thrips. Oddly enough, I’m not seeing much in the way of other bad bugs…yet. The season is young. Only the plants that overwintered have bloomed so far. I do have fat buds on Odyssey, HH Serenity, 20th Ave Memory and a few more. Looking forward to those!

SteveM

JessieC I still am not 100% sure what a thrip looks like!

Thrips are difficult to see with the naked eye but, as mentioned above, if you tap a flower on a piece of dark paper/material you will see the thrips that fall onto the paper. Some mite damage can resemble thrips damage but it is usually more of a stippling pattern instead of the "raspy", jagged thrips damage. A good hand lens helps make the proper ID so you can choose the appropriate control measures. If I were not selling flowers commercially I would use beneficials and let nature take its course. Spraying is the only thing I dislike (hate) about growing dahlias.