Garden Basics with Farmer Fred

221 Whitefly Control. Bermudagrass Eradication Tips

August 19, 2022 Fred Hoffman Season 3 Episode 221
Garden Basics with Farmer Fred
221 Whitefly Control. Bermudagrass Eradication Tips
Show Notes Transcript Chapter Markers

Whiteflies. They can overwhelm a garden full of vegetables and flowers, as well as certain trees and shrubs, especially during warm weather. Whiteflies excrete sticky honeydew and cause yellowing or death of the leaves. The good news is: there are a lot of beneficial insects  that can help you do battle against whiteflies.
In some areas of the country,  Bermudagrass is a desirable turf type for a lawn. The problems begin when it starts spreading to other parts of the yard. If you’re looking to eradicate bermudagrass without the use of chemicals, we have some answers.
We’re podcasting from Barking Dog Studios here in the beautiful Abutilon Jungle in Suburban Purgatory. It’s the Garden Basics with Farmer Fred podcast, brought to you today by Smart Pots and Dave Wilson Nursery. And we will do it all in about 30 minutes. Let’s go!

Whiteflies on Citrus Leaf  (Photo: UCIPM)

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Smart Pots
Dave Wilson Nursery

Whitefly Management Guidelines (University of California)
Plants That Attract Beneficial Insects
Yellow Sticky Traps for Whitefly Monitoring
Soil Solarization for the Garden  (University of California)
Bermudagrass Control Tips (University of California)

Rincon-Vitova Insectaries
Beneficial Insectary

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GB 221 TRANSCRIPT Whiteflies. Bermudagrass.

Farmer Fred  0:00  

Garden Basics with Farmer Fred is brought to you by Smart Pots, the original lightweight, long lasting fabric plant container. It's made in the USA. Visit slash Fred for more information and a special discount, that's

Welcome to the Garden Basics with Farmer Fred podcast. If you're just a beginning gardener or you want good gardening information, you've come to the right spot.

Farmer Fred  0:31  

Whiteflies. This sucking insect garden pest is easy to spot. Shake a plant, and if all of a sudden there’s a cloud of flying white insects in your face, it’s whiteflies. They can overwhelm a garden full of vegetables and flowers, as well as certain trees and shrubs, especially during warm weather. Whiteflies excrete sticky honeydew and cause yellowing or death of the leaves. The good news is: there are a lot of beneficial insects, the garden good guys, that can help you do battle against whiteflies. Another warm season yard issue for those who live in milder climates: the proliferation of bermudagrass. In some areas of the country, it’s a desirable turf type for a lawn. The problems begin when it starts spreading to other parts of the yard, which it can do, quite easily, and in a variety of ways. If you’re looking to eradicate bermudagrass without the use of chemicals, we have some answers. We’re podcasting from Barking Dog Studios here in the beautiful Abutilon Jungle in Suburban Purgatory. It’s the Garden Basics with Farmer Fred podcast, brought to you today by Smart Pots and Dave Wilson Nursery. And we will do it all in about 30 minutes. Let’s go!

Farmer Fred  1:45  

One pest that a lot of gardeners have, and it seems to be a lot in the shade, although they can appear in sunny gardens as well, are white flies. They're tiny sap sucking insects that can get quite abundant in both vegetable and ornamental plantings, especially during warm weather. They excrete honeydew that causes yellowing or the death of the leaves. Outbreaks usually occur when either the plant is in the wrong place or there's a natural biological control disruption. Management is difficult once populations get high. Guess who's here? America's favorite retired college horticultural Professor, Debbie Flower, with more on white fly controls. Whiteflies. Grrr.

Debbie Flower  2:29  

Yeah, they're can be very frustrating, especially in a greenhouse, because the things that will eat them, the beneficial insects or the natural enemies, aren't in the greenhouse. That can be solved, the predators and parasites that attack white flies can be purchased and released. And to do that, you need to contact an insectary, they are places that actually grow these insects and send them to you, in a form that you can release in a situation like a greenhouse. Outdoors, releasing them is less effective because these beneficials can go wherever they want to go, maybe won't be as able to find the whitefly population, but in a greenhouse that can be very effective control.

Farmer Fred  3:11  

And there are all sorts of different whiteflies as well. And once you get them they are very tough to control.

Debbie Flower  3:17  

They are. And they're the best way to control them is to get the beneficials. Which often means you have to put up with a population of whiteflies for a little while. There are grapes on the fence between myself and the house behind me. They're not my grapes, they belong to the person behind me. And I was pruning them to keep them out of my walking space on my side of the fence. And they were full of whiteflies, and I did absolutely nothing because I knew that the beneficials then would be able to come in and attack the whiteflies and the way to get a good population of beneficials is to have what they eat there, which is the insect itself.

Farmer Fred  3:59  

What are some of these garden good guys that can go after white flies?

Debbie Flower  4:03  

Lacewings and lady beetles and the little tiny wasps are three that will go after the whiteflies. Whiteflies have, what we call, complete metamorphosis. So the adult lays an egg, the egg hatches into a larva and the larva generally is a non-moving white blob on the underside of the leaf. It may have fringe around it. It may not. And then the larva goes into a pupal stage which is in this blob stage. And then it hatches, then becomes an adult, and flies away. Whiteflies mate with each other and the process starts all over again.

Farmer Fred  4:37  

We've talked about in the past the benefits of having “good bug hotels”, someplace for the garden good guys to raise their young and have a meal that isn't a bug. For that, you need to put in other plants. You mentioned you could buy some of these good guys at an insectary then release them, but you gotta have the plants established that they will want to stay in your yard, right?

Debbie Flower  4:58  

The good guys need to eat and they're going to need protein which is going to be eating the white fly in the larval or pupal stage. But they also need some sugar and that's what comes from the flowers and the plants that are nearby. So you need a population of those flowers nearby so that they can get a balanced diet.

Farmer Fred  5:16  

Yeah, and as far as attracting lacewings, planting plants like Yarrow or Angelica, golden Marguerite, cosmos, Queen Anne's lace, fennel. Even dandelions attract the good guys.

Debbie Flower  5:31  

Have you seen those signs? People putting signs in their yard that say, “I’m not growing weeds, I'm feeding the insects.” I'm feeding the insects. 

Farmer Fred  5:37  

Well, there's a whole other show we could do about the benefits of dandelions. 

Debbie Flower

Yes, in a landscape. 

Farmer Fred

Yeah. And if you have dandelions in your lawn, you should be thankful for that. It's improving the soil. 

Debbie Flower

They have that deep taproot. 

Farmer Fred

Ladybugs, of course, need a home too. And we've talked about this before, too, is the fact that if you buy ladybugs and release them, 95% of them, according to university studies, will fly away home.

Debbie Flower  6:04  

Ladybugs are collected in dormancy, and their first instinct once they come out of dormancy is to fly for miles, like 25 miles. Yeah.

Farmer Fred  6:14  

The ladybug, if you want to release them, maybe you need some plants where they may want to live and one of the favorite habitats for ladybugs are ornamental grasses. 

Debbie Flower  6:25  

Mm hmm. They will overwinter in there. Yes, down deep.

Farmer Fred  6:28  

 Yeah, in Deer grass, muhlenbergia, and things like that. So that's something to consider. Besides some of the other plants that we've talked about that attract beneficials. The yarrows. Bugle weed is a good one. Coriander. California buckwheat, is one of my favorite California native plants for the number of beneficials that attracts.

Debbie Flower  6:49  

There are many different California buckwheat, and they're all beneficial in that regard.

Farmer Fred  6:54  

And what's nice about the California buckwheat, it has a bloom season here in California from May through December. It's very long. Yeah, yeah. And the flowers actually changed color through the season much like a seed would do. It's always nice, then to have those plants around so that you can raise your own Ladybug population.

Debbie Flower  7:11  

Or certainly feed the one that flew 25 miles from someplace else.

Farmer Fred  7:15  

Yes. All right. Again, with whiteflies, much like with aphids, there are reflective mulches that might work. Because it disorients them when they fly, because they look down and they see a reflection of the sky so they think, I'll just keep moving.

Debbie Flower  7:31  

I'm not in the right place.

Farmer Fred  7:33  

Yeah. How about ants and whiteflies? Are ants a bigger problem for the gardener, as far as herding whiteflies around as they are with herding aphids around?

Debbie Flower  7:42  

I've seen ants way more on the aphids than on the whiteflies. Whiteflies, at least some of the species as you said, there are many different white flies to produce honeydew and the ants are attracted to that and will protect the whiteflies from what we call the good guys.

Farmer Fred  7:55  

And again, a clean plant is a happy plant that attracts beneficials, so wash off your plants.

Debbie Flower  8:00  

They don't like the dust, right? The beneficials.

Farmer Fred  8:03  

Now I remember one winter when I decided I'm going to grow tomatoes in the greenhouse for the winter, because I don't want to buy supermarket tomatoes from November through May or June. 

Debbie Flower

Were you successful? 

Farmer Fred

Yes and no. For many reasons, the biggest problem growing a small determinate tomato in a greenhouse is the whiteflies.  And it got to the point where there were just so many whiteflies, I'm got rid of the those plants that attracted the most white flies, and that's a strategy. You put them in the trash, and then control the rest. And it got to the point in the greenhouse where to control the whiteflies, besides throwing away the most infested plants. I use an organic pyrethrin-based insecticide called Bug Buster O, it was organically registered. And the problem is being able to spray all portions of the plant. It has to be applied repeatedly in order for it to be effective, but it's still an ongoing battle.

Debbie Flower  9:07  

Yes, it's tough to get the pesticide onto the whiteflies, because when you touch the plant or get near it, they fly away. So you want to do some of the control on the other life stages.

Farmer Fred  9:19  

I find it interesting that the pyrethrin insecticide is registered organic.

Debbie Flower  9:25  

Pyrethrin is refined pyrethrum. Pyrethrum is collected from flowers, the Chrysanthemum. And if you get pyrethrum then you're getting the whole molecule. And if you're getting pyrethrin you're getting a slightly refined extract of that, but they both work. They're both naturally occurring substances on the planet and when they break down, they break it down into naturally occurring substances on the planet. If you get pyrethroid, you're getting one that's made in a lab. And It will not break down into something that already exists on earth.

Farmer Fred  10:03  

And Bug Buster O, made by Monterey, is listed for control on 1-2-3-4-5-6-7-8-9-10- 11-12- 13-14 -15- 16 17- 18-19 lines of bad guys. That's a lot of pests.

Debbie Flower  10:18  

There's like eight or nine on pests listed on each of those 19 lines. So we're looking at 200. Maybe?

Farmer Fred  10:25  

Yeah, close to. I mean, white flies is down there under W. They're, alphabetized. Yeah, aphids under a. So you got Japanese beetles on there, too. But again, you gotta read and follow all label directions.

Debbie Flower  10:39  

And if that little wasp is, is inside, or is hovering around the whiteflies, trying to find a nice pupal case to lay its eggs in, you will kill it as well with the pyrethrum.

Farmer Fred  10:50  

Exactly. And bees, as well, should not be around when you're using it.

Debbie Flower  10:54  

they're very sensitive. Yeah,

Farmer Fred  10:55  

I have to worry about that in a greenhouse. But still, you're using it outdoors. And frankly, I think Bug Buster O was probably only meant for outdoor application. I don't know if it's registered for use indoors. 

Debbie Flower  11:07  

And that's a good point to following the label. It includes using it where it  says you can use it. If it says an indoor situation, then you can use it in a greenhouse. But if it does not say that or does not specify a greenhouse, specifically, it is illegal to apply it in a greenhouse.

Farmer Fred  11:23  

In my defense, I used it probably 20 years ago for that purpose. Maybe it wasn't on the label then. 

Debbie Flower  11:30  

or you took the plants out and treated them outdoors and then put them back.

Farmer Fred  11:33  

 I like that. Okay, we'll run with that. Okay. All right. Yeah, white flies are tough. There's no doubt about it.

Debbie Flower  11:39  

You can use a yellow sticky tab to monitor whiteflies as well as for aphids, and it also attracts thrips and fungus gnats and shore flies, several of the pests that we find annoying in the garden. But with whiteflies, it's pretty obvious. They fly into your face. Yeah, you kind of don't need to monitor that way. Although it would help you monitor quantities. When I worked for Sacramento County Cooperative Extension in the early 90’s, we had a huge infestation of ash white fly, so much so that people were unable to picnic outside because there were so many whiteflies. And it's called ash whitefly because one of its places that it hung out was in ash trees. And there are a number of ash trees in the local region. And so one of our jobs was to make a suction instrument. And it was a bottle, and it had two holes in the stopper in the top with two pieces of metal coming out. And you attach the plastic tube to each of those pieces of metal. And then we drove down to a part of California that had good control from natural enemies of ashwhitefly and used our little jar things and we sucked on one tube to create a vacuum in the jar and use the other tube to vacuum up white flies and their predators. We released those when we got back. That was a fun day.

Farmer Fred  13:00  

I think the reason the ash whitefly population has been reduced in our area is because the Modesto ash trees basically died.

Debbie Flower  13:07  

Yes, that's part of it. But also we then came and brought what was the contents of our jar which had the beneficials in it and released it in high population, Ash whiteflyareas. So I was part of that too.

Farmer Fred  13:19  

Congratulations. Thank you. All right, basically pesticides are the last resorts, then oils, soaps, any sort of chemicals,

Debbie Flower  13:27  

Always the last resort, you want to try everything else. First, you want to try thinning out the plants so the beneficials can get there. Wash the plants so the dust is removed, controlling any ants that happened to be tending to the whiteflies, removing the most infected plants, especially if it's in a greenhouse situation, watching for beneficials. And if you see pupal cases that are black there, you've got beneficials in them. And you have to wait  for the beneficials to show up. You have to have some patience to deal with this. But yes, as a last resort, you use the pesticides.

Farmer Fred  13:58  

And remember, too: those good bug hotels are important for building up the beneficial insect populations that can help keep future white flypopulations at bay. 

Debbie Flower

Very true. 

Farmer Fred

All right, whiteflies. We can do this. thank you, Debbie.

Debbie Flower  14:12  

You're welcome Fred.


Farmer Fred  14:17  

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Farmer Fred  16:11  

We're here at Harvest Day at the Fair Oaks Horticulture Center. It's a beautiful Saturday in August and yes, people have questions. Now if only Debbie Flower ,America's favorite retired college horticultural professor, was here to help. But then again, I think I can handle this one without her here. Hi. Thanks for dropping by.

Suzie in Sac  16:29  

Hi there. My name is Susie and I live in Sacramento County.

Farmer Fred  16:32  

Susie, what's your question?

Suzie in Sac  16:34  

I have a raised bed that has been invaded by Bermuda grass.

Farmer Fred  16:38  

What sort of raised bed is it? Does it have wood sides or brick or…?

Suzie in Sac  16:41  

it has wood sides, it's three by eight, about two feet deep.

Farmer Fred  16:47  

Okay, three foot width is excellent for a raised bed, because you can reach the middle without stepping into the bed. As soon as you get to over four feet, you start having problems. but with three feet, you can get in there easily to do something like, Oh, I don't know, remove Bermuda grass, for example. 

Suzie in Sac

For example, yes.

Farmer Fred

Bermudagrass is a Triple Threat weed, because if you let it go and just let it grow, it's going to reproduce by seed from those little turkeyleg-like flowers that pops up and then spread seed that way. Underground, you have rhizomes and stolons along the surface. The rhizomes basically are the underground root system of the plant. And the stolons are the trailing part that go out horizontally that I'm sure you've seen with Bermuda grass. All three of those can reproduce vegetatively, which is just a fancy way of saying you can't kill it unless you do certain things.

Suzie in Sac  17:39  

Right. So that's my issue. And if I managed to get all of the Bermudagrass, dig it out of the raised bed, what do I do to keep it from coming back?

Farmer Fred  17:50  

That's a good question. Because you can never kill Bermudagrass, a portion of Bermudagrass, if you just left a like an inch of a Bermudagrass in that raised bed, it could stay there and not germinate or spread for 50 years, and then all of a sudden, your grandchildren will be pulling the Bermudagrass from the raised bed. So the best option, after you've basically taken out as much as you can, is to solarize the soil. And that's a process of using clear plastic. During the warm months, June, July, August, you only need to do it for about eight to 10 weeks in that time. But a raised bed is a perfect way to do soil solarization because you've already got the frame, you can secure the clear plastic along the edges and just leave it there. And that soil is going to heat up to 140 degrees, it's going to kill weed seeds, it's going to kill whatever is left of the Bermuda grass down to a foot and a half to two feet. But the trick is to use clear plastic and do it during the hottest time of the year, which means you're gonna lose that bed for summer gardening.

Suzie in Sac  18:57  

That's okay, I can I can lose it for one summer if it means I'll have a clean bed to start with.

Farmer Fred  19:01  

Okay, there are some special clear plastics you can buy. But actually, if you just go to the big box store, go to the paint department and look for their clear plastic drop cloths. They're usually two mil or four mil thick, just use that. But the key though, when you're solarizing, before you solarize, after you've cleared off the weeds, before you put that clear plastic down, soak the bed thoroughly. Because water is going to move the heat even deeper. And it's going to allow that heat to get those weeds or particles that were left out. And the other thing, too, is to make sure air doesn't seep in from the sides. So you want to secure it along the edges all the way around. But a raised bed is very good for that. But sometimes if you got a heavy windstorm, it might rip. Be sure you get out there and seal that rip with some duct tape or whatever. And it works. I've done it . I had a 2000 square foot bermudagrass lawn. 

Suzie in Sac

You’re asking for trouble there.

Farmer Fred

well, yeah, exactly. And then,  when you say, “Well, I don't want to Bermuda grass lawn anymore, I want to put a garden in here”. That's when the fun begins. And that involves  getting a sod cutter, taking it out, and then solarizing that area. And I did it for eight weeks during June and July, and no Bermuda grass has reappeared in that area. So really the key though, - and there are several keys to this, obviously, - so I hope you have a big key ring. The one major key, though, is when you're done solarizing the soil, put some mulch on top of the bed, maybe three to four inches of mulch, because that will help not let anything that may have escaped to germinate because they need light to germinate. And then you can just move that mulch aside when you go to plant.

Suzie in Sac  20:49  

Okay, and how long do I need to keep the plastic cover on? 

Farmer Fred  20:53  

depends on how warm it is. Now here in Sacramento this summer, it's we've had several strings of 100 degree days in a row.  You can get away with eight weeks, six to eight weeks. However, if you live in a cooler climate, you may want to leave it on a little bit longer. But the key is do it whenever the hottest time of the year is wherever you live. So here in Sacramento County, that's basically for mid June through mid August, maybe even late August. It might be a little late to start now. Depends on how you think the weather is gonna turn.

Suzie in Sac  21:24  

Probably so but it's okay. It gives me a plan for next year.

Farmer Fred  21:28  

So there you go. And in the meantime, you can be just pulling away on that Bermuda grass.

Suzie in Sac  21:32  

So excited.

Farmer Fred  21:34  

Thanks for the question.

Suzie in Sac  21:35  

Thank you, Fred.


Farmer Fred  21:36  

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Farmer Fred  22:53  

Nothing scares me more than seeing a group of tree trimmers emerge from an unmarked truck and start pruning or removing the neighbors trees. My fear is for the financial health of my neighbors. If those workers, who may or may not be certified arborists, are not currently licensed, bonded and insured, those neighbors may be financially responsible if one of the workers is injured on their property, or the tree trimming activity causes damage to their house or their neighbors house or property. And the fact that everyone arrived in unmarked vehicles? That’s a red flag. On Friday’s Beyond the Garden Basics newsletter and podcast, we find out more information to help you choose a qualified tree trimming firm. Or tree removal firm. Especially if your tree is a victim of a very common summertime occurrence, sudden limb failure, when big branches crash to the ground, on a hot, non-windy afternoon. And yes, besides, arborists, we will have more information about this poorly understood problem of old, large oaks, eucalyptus, elms and ash trees. The key to reducing the chance of this happening on your property, is to bring in an arborist for an evaluation. Perhaps a consulting arborist. It’s all part of Friday’s Beyond the Garden Basics newsletter and podcast.

 Find a link to the newsletter in today’s show notes, or visit our website, Garden Basics dot net, where you can sign up to have the free, Beyond the Garden Basics newsletter delivered to your inbox each Friday. Also at Garden Basics dot net, you can listen to any of our previous editions of the Garden Basics podcast, as well as read a transcript of the podcast episode you are listening to now. That’s at Garden Basics dot net. For current newsletter subscribers, look for  All About Arborists and sudden limb failure in the next Beyond the Garden Basics newsletter on the morning of Friday, August 19th in your email. Take a deeper dive into gardening, with the Beyond the Garden Basics newsletter. And it’s free. Find the link at garden basics dot net.

Farmer Fred  25:03  

Garden Basics With Farmer Fred comes out every Tuesday and Friday and is brought to you by Smart Pots and Dave Wilson Nursery. Garden Basics is available wherever podcasts are handed out. For more information about the podcast, visit our website, GardenBasics dot net. That’s where you can find out about the free, Garden Basics newsletter, Beyond the Basics. And thank you so much for listening.

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Eradicating Bermudagrass
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Beyond the Garden Basics Newsletter