Western Flower Thrips
WESTERN FLOWER THRIPS
Thrips - I wish I had a picture to share but I've killed all mine for now so you'll have to go look it up if you want to see some. Sorry. I have had them on occasion, I just didn't take any pictures. They move too quick!
Thrips are the african violets most dangerous pest according to some growers. Mites can be nearly impossible to get rid of and kill your plant if left untreated and a lot of growers will just toss a plant with mites rather than try to save it. But thrips are everywhere! It seems like they target your beautiful violets at every turn. And they can carry INSV - Impatient Necrotic Spot Virus and spread it to wipe out your whole collection. So can any pest infestation left untreated. Penn State University Extension has a very good page on INSV and says "The virus causes a wide variety of symptoms including wilting, stem death, stunting, yellowing, poor flowering, 'chicken pox-like' sunken spots on leaves, etches or ring spots on leaves, and many others." Their page also has information on Western Flower Thrips.
Western Flower Thrips are a big problem in commercial greenhouses, orchards and nurseries where they monitor their activity with sticky traps to get an idea of the population numbers so they can know when to spray to keep down the damage done. They never expect to totally eradicate them because they come in on the wind and it's a big windy world outside! They can't kill every thrip in the world at the same time so the ones that live through an insecticide spray will develop the resistance to it as a survival mechanism. That's the problem.
In a greenhouse environment, they can never kill them all. So they might be a big deal to the commercial grower but not so much to the average home grower. with a good strategy. The home growing environment is a lot different than the open commercial growing environment where you should have a lot more control in a smaller confined area. But we tend to use some of the same products on our violets that commercial growers do and the industry does provide lower concentrations for home users.
In the greenhouse, they rotate their insecticides to kill the resistant strains that may have survived another insecticide and become resistant to it. Does that make sense? So far so good. You can do that at home too if you think your last insecticide dip or spraying was not very thorough. But thrips can come in on the wind through your screens so how do you know if you have new ones or old insecticide resistant ones that survived? You don't so the best prevention is to rotate your insecticides at home too.
My favorite product is spinosad and I use it in low dosage on every plant that comes into my house. I don't intend to leave any survivors to become resistant. But, I also rotate my insecticides when I do have to use them on all my plants as a preventative.
DAMAGE DONE
I don't want to repeat any information that is already out there so I can just tell you about my experience and point you to a few good research sources so you can gather correct information to put with your own growing experiences.
According to the University of Florida thrips in general can cause all kinds of damage. "Common symptoms include bronzed, curled, or stunted leaves. Infested plants decline over time, and severe infestations can cause total leaf loss." University of Florida on Thrip Damage
In my experience, the best preventative is a pro-active spraying of a 3 in 1 product weekly or bi-weekly. Most bugs find neem oil and essential plant oils in general distasteful so it is a deterrent and will not harm your plants but you need to shake it up as you apply it to get even coverage.
As a home grower, you do not want to just cut down on the number of thrips in your growing area because you can completely control them unlike an outdoor operation where they can't. So, you want to kill them all and you can kill them all at once in your little enclosed environment (at least until the next time).
When you kill them all, there are none left to develop a resistance to your product. The new ones you get after that will all be new brought in from the outside and not necessarily resistant to your application. That being said, there is no way to know for sure if they are already resistant from other insecticide applications to whatever product you use.
According to the University of California western flower thrips can cause leaves to drop. "Thrips feeding can stunt plant growth and cause damaged leaves to become papery and distorted, develop tiny pale spots (stippling), and drop prematurely." UC IPM on Western Flower Thrips
So, Western Flower Thrips are a real threat to african violet growers but not the only thrip that can attack them. The best way to fight them is to learn all about them and have a preventative plan in place.
Thrips - I wish I had a picture to share but I've killed all mine for now so you'll have to go look it up if you want to see some. Sorry. I have had them on occasion, I just didn't take any pictures. They move too quick!
Thrips are the african violets most dangerous pest according to some growers. Mites can be nearly impossible to get rid of and kill your plant if left untreated and a lot of growers will just toss a plant with mites rather than try to save it. But thrips are everywhere! It seems like they target your beautiful violets at every turn. And they can carry INSV - Impatient Necrotic Spot Virus and spread it to wipe out your whole collection. So can any pest infestation left untreated. Penn State University Extension has a very good page on INSV and says "The virus causes a wide variety of symptoms including wilting, stem death, stunting, yellowing, poor flowering, 'chicken pox-like' sunken spots on leaves, etches or ring spots on leaves, and many others." Their page also has information on Western Flower Thrips.
Western Flower Thrips are a big problem in commercial greenhouses, orchards and nurseries where they monitor their activity with sticky traps to get an idea of the population numbers so they can know when to spray to keep down the damage done. They never expect to totally eradicate them because they come in on the wind and it's a big windy world outside! They can't kill every thrip in the world at the same time so the ones that live through an insecticide spray will develop the resistance to it as a survival mechanism. That's the problem.
In a greenhouse environment, they can never kill them all. So they might be a big deal to the commercial grower but not so much to the average home grower. with a good strategy. The home growing environment is a lot different than the open commercial growing environment where you should have a lot more control in a smaller confined area. But we tend to use some of the same products on our violets that commercial growers do and the industry does provide lower concentrations for home users.
In the greenhouse, they rotate their insecticides to kill the resistant strains that may have survived another insecticide and become resistant to it. Does that make sense? So far so good. You can do that at home too if you think your last insecticide dip or spraying was not very thorough. But thrips can come in on the wind through your screens so how do you know if you have new ones or old insecticide resistant ones that survived? You don't so the best prevention is to rotate your insecticides at home too.
My favorite product is spinosad and I use it in low dosage on every plant that comes into my house. I don't intend to leave any survivors to become resistant. But, I also rotate my insecticides when I do have to use them on all my plants as a preventative.
DAMAGE DONE
I don't want to repeat any information that is already out there so I can just tell you about my experience and point you to a few good research sources so you can gather correct information to put with your own growing experiences.
According to the University of Florida thrips in general can cause all kinds of damage. "Common symptoms include bronzed, curled, or stunted leaves. Infested plants decline over time, and severe infestations can cause total leaf loss." University of Florida on Thrip Damage
In my experience, the best preventative is a pro-active spraying of a 3 in 1 product weekly or bi-weekly. Most bugs find neem oil and essential plant oils in general distasteful so it is a deterrent and will not harm your plants but you need to shake it up as you apply it to get even coverage.
As a home grower, you do not want to just cut down on the number of thrips in your growing area because you can completely control them unlike an outdoor operation where they can't. So, you want to kill them all and you can kill them all at once in your little enclosed environment (at least until the next time).
When you kill them all, there are none left to develop a resistance to your product. The new ones you get after that will all be new brought in from the outside and not necessarily resistant to your application. That being said, there is no way to know for sure if they are already resistant from other insecticide applications to whatever product you use.
According to the University of California western flower thrips can cause leaves to drop. "Thrips feeding can stunt plant growth and cause damaged leaves to become papery and distorted, develop tiny pale spots (stippling), and drop prematurely." UC IPM on Western Flower Thrips
So, Western Flower Thrips are a real threat to african violet growers but not the only thrip that can attack them. The best way to fight them is to learn all about them and have a preventative plan in place.
