GB 136 Gophers, Cucumbers TRANSCRIPT
28:35
SPEAKERS
Mary in VA, Debbie Flower, Roger Baldwin, Farmer Fred
Farmer Fred 00:00
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 SmartPots.com slash Fred for more information and a special discount, that's SmartPots.com/Fred.
Farmer Fred 00:20
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 00:32
There is one four legged pest that ravages gardens and orchards throughout the West, the Midwest and the South. They are pocket gophers, so named for the furry pouches outside their mouth that can store food. Pocket gophers can destroy the roots of annuals, perennials, trees and shrubs. Today, we talk with a gopher control expert on which tactics will work and which don't work to control gophers. Also, why would a cucumber plant just die? We tackle that question from a gardener in Virginia. It's all on episode 136 of the Garden Basics with Farmer Fred podcast, brought to you today by Smart Pots. And we'll do it all in under 30 minutes. Let's go.
Farmer Fred 01:19
Pocket gophers can be serious pests, particularly in young fruit tree and nut orchards. While herbaceous cover crops are their preferred food, pocket gophers will also feed on the bark of tree crowns and roots. And when those cover crops or weeds dry up, gophers bark consumption may become extensive enough to girdle and kill young trees, or even reduce the vigor of older trees. How do you control gophers? And moreso, how do you not control gophers? We're talking with Roger Baldwin. He's a wildlife specialist with the Department of Wildlife, Fish and Conservation Biology at UC Davis. And Roger, there have been all sorts of attempts to control gophers by many means over the years. And I guess maybe we should start off with what doesn't work when it comes to controlling gophers?
Roger Baldwin 02:07
Good question. There are a variety of different strategies that have been considered over the years. And as you have alluded to, some work relatively well, some not so well. Some of the ones that don't work very well, for example, probably the question I get most often when I'm now giving extension presentations is whether or not the use of bubblegum in burrow systems will work for reducing gopher populations. As strange as that may seem, somebody apparently had indicated that that worked many decades ago, and it actually has been tested in a couple of different situations. And, I can assure you that bubble gum has never tested as an effective approach for managing pocket gophers. There's lots of repellents that are marketed for gophers. And at this point in time, we have not seen any positive feedback from the use of repellents for keeping gophers out of particularly large areas, but even smaller areas. To that extent, sometimes exclusion is considered for use to keep gophers out of areas, whether it be fencing buried underground, or even wire baskets around newly planted trees. Wire baskets can reduce damage to root systems, but it's just not typically going to be a cost effective or practical approach over an orchard type system. It's something that would only be used in and around homes and some of those kinds of areas where you're just planting a few trees. Another approach that's discussed quite a bit is the use of owl boxes and other predators to control rodent populations. It's something that continues to be looked at. At this point in time, we're uncertain as to how effective that approach is. It does appear that if gopher populations are fairly substantial, that the use of owls and other predators probably are not going to be enough to reduce gopher populations in a particular area. In large part due to the reproductive output of a lot of rodent species, as gophers. We're hopeful that maybe in some situations where gopher populations already relatively low that there could be some benefit from owls to the use of owl boxes to keep those populations at relatively low levels, but we're still not certain on that. We're continuing to look along those lines.
Farmer Fred 04:40
I imagine that when you were talking about repellents that would include gas cartridges, smoke bombs, devices that make sounds or vibration,s or electromagnetic devices.
Roger Baldwin 04:51
So for repellents, we're generally considering chemical repellents. So these would be things that you would might potentially spray on the ground with the hopes of pushing gophers out of certain areas, and those have not historically tested very effective. The other thing that we would be considering in that category would be the vibrating stakes and things along those lines that you see sold at certain stores. Those have also not tested all that well. As far as the gas cartridges and some of the other devices for which you're introducing a toxic gas into into the burrow system, those are considered fumigants. And they're a different category that we can talk about, if you want.
Farmer Fred 05:31
Talk a little bit about the burrow itself, how extensive is a gopher burrow system? How far does it run?
Roger Baldwin 05:39
It varies quite a bit. They can be pretty extensive systems, probably the bigger question is, how are these systems set up? And how do they change over time, because they can run many feet, maybe up to 120 feet, and in one particular direction. Sometimes, although that's certainly on the extreme end, realistically, what you generally have are several different layers with tunnel systems, you kind of have an upper layer, which is usually within six to 10 inches of the surface of the soil. And those are the more short term tunnel systems where they're digging around looking for food sources, then they usually have some deeper tunnel systems, which are a little more permanent. They're certainly there for a longer period of time. They might be connected to some nesting chambers, and other associated structures like that, The thing about gophers, they're constantly creating new tunnels. And so when they're done with old parts of their systems, they'll backfill those tunnel systems up and continuing to dig new tunnels. So they're constantly digging throughout the landscape, moving around.
Farmer Fred 06:44
Now, I know that flood irrigation may or may not work, but what about a really wet winter? I think that would be a double edged sword. Yeah, they might be flooded out temporarily, but the accompanying new green growth above may spur them on to increase their populations quickly.
Roger Baldwin 07:01
Yeah, I think that's exactly right. And, you know, we've never been able to officially test what kind of a true impact that has. But generally speaking, we know that flood irrigation is an apparently decent tool for managing gophers, because it generally forces them up to the surface or they drown. And when they're forced up to the surface, then they're susceptible to some of the natural predators that are out there, because they don't have avoidance strategies to get away from that. And so when you have these heavy rainfall events, you're going to get a lot of flooding in a lot of these fields. And, of course, many fields were completely flooded. And so that likely eliminated gophers from that particular field. If you have fields that are partially flooded, then probably that gets rid of some of those gophers and forces, the rest on to some of those other outlying areas. And so yeah, it may do some of the work, that particular lowering populations in those areas. But of course, once that water recedes, now, you've got soil moisture, that is really beneficial for weeds and crops in these different cropping systems. And so now you have an abundance of food. Plus, you have lower gopher densities from that flood event, which means there's less pressure on those resources. So they'll have larger litters, and those litters will survive at a greater rate. And so you could get a real proliferation of gophers after that event. So it's a real give and take situation there.
Farmer Fred 08:28
I think we talked about how they can damage tree crops, the fruit trees, the nut trees. Gophers can gnaw on plastic irrigation lines. And those tunnels, of course can allow irrigation water to just bypass roots and go on down the tunnel. Is there an effective control for protecting a drip irrigation system from gophers?
Roger Baldwin 08:50
Yeah, you're exactly right. There's been a real desire to move to subsurface drip irrigation, a lot of different cropping systems because it uses less water. And of course, we're really concerned about water usage here in California. But the problem is that if gophers are present in an area that subsurface drip is put in about the same depth that the gopher tunnel systems occur. So as the gophers dig around, they come across these, these drip tapes, and then they start chewing on them, and then those leaks are really difficult and costly to repair. Unfortunately, the answer is no, we don't have any great strategies for mitigating that damage. Right now. We've looked at repellents, potentially being forced through those systems to try to deter gophers from you know, hanging out in the certain areas and chewing on that drip tape and that hasn't proven effective yet. Perhaps eventually there will be a repellent developed that might work. We've looked at trying to keep gophers out of certain areas with exclusion fencing. That hasn't worked as well. Currently about the only strategy is just to, to stay on top of the gopher populations and remove them so that they don't build up to levels where they're causing damage to the drip tape. But, you know with drip tape it's almost a zero tolerance policy. Even a few gophers can cause quite a bit of damage out there and so it becomes costly to try to remove those gophers to keep the drip tape functional.
Farmer Fred 10:14
Do they tend to damage half inch irrigation lines and micro spoiling sprinklers less?
Roger Baldwin 10:19
So those structures that are above ground are not typically damaged much by gophers, they are damaged, of course by a lot of other rodent species such as ground squirrels, mice and voles. But gophers spend the vast majority of their life below ground and so they generally do not come above ground and chew on those structures.
Farmer Fred 10:42
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Farmer Fred 12:06
We are talking with Roger Baldwin, wildlife specialist with the Department of Wildlife, Fish and Conservation Biology with UC Davis. We are attempting to control gophers today out in the orchard. So Roger, let's talk about some effective controls for managing that gopher population, which can reach as high as 30 to 40 per acre, I would I would think that you have to go back to the traps.
Roger Baldwin 12:30
Yeah, there's a variety of different strategies can work for gopher control. Those include the use of trapping. There's a variety of different traps out there. And in fact, a previous colleague of mine wrote a book on on the different traps that have been patented over the last 100 plus years, and it's probably an inch thick. So there's certainly a large number of traps that have been developed and tried over the years, one of the traps that we've tested that probably has worked, the best for us is a trap called the Gophinator trap, it's worked really well, it's a good size to fit into the tunnel system, some of the traps are a little larger, this one's a little bit smaller. And so it's easier to fit into the tunnel system. And it seems to catch gophers at a very high rate, particularly larger gophers, which are responsible for a lot of reproduction out there. So we certainly want to eliminate those larger gophers from the population if we want to have effective control. And, you know, based on a lot of the research we've done over the years, trapping certainly is very effective. We've seen 90 plus percent removal rates after two trapping periods through a particular field. And in some cases, after three trapping periods, we've been able to completely remove gophers from some fields. And that's with densities of 30 to 40 gophers per acre. So trapping certainly is a very effective tool for getting rid of gophers from fields. Now the big question is, is it cost effective? The short answer is, I think in many cases, yes, it definitely is. But it does depend on soil types. Those soil types that are more conducive for easier digging, particularly those with shallower tunnel systems, those that have more sandy or loamy type soils, trapping is a very cost effective strategy, as cost effective or more cost effective than most of the other techniques we've looked at. If you're dealing with heavy clay soils, though, particularly once those soils start to dry out, then it becomes more difficult to probe and find those tunnel systems and dig down and set traps. And so with those systems, it's probably not as cost effective as other strategies. But regardless, trapping probably should be a tool that that anybody who's interested in gopher control should be considering as part of an integrated approach.
Farmer Fred 14:54
Now you mentioned the Gophinator, a pincer type trap, and that is probably well known along with the Maccabee and the cinch traps. But the Maccabees had a problem over the years of larger gophers sort of dragging the trap, but down further down the burrow and you never catch it.
Roger Baldwin 15:12
What we think the problems with the Maccabee trap is, is kind of how it captures the gopher it kind of has an upward thrusting motion. And in so doing, the larger gophers, we think, is kind of pushing, sort of out of the trap, and it catches them a little bit but not completely, and then they're able to eventually pull free from the trap. The Gophinator trap has a different capturing mechanism, which we think holds them in there to a greater rate, or regardless of the trap that you use, you really do have to take the traps down, because if you don't, they can back up a little bit into that tunnel system. And then you will lose the trap in that capacity. So staking traps down is certainly an important strategy regardless of the trap that you're using. So we did do a research project here a couple years back where we looked at, at a tethered type cable around the jaws of the trap. The general purpose of this, is because we think the larger gophers are able to pull out of those traps, by adding that tether to that trap it keeps them from being able to pull out of the trap. And so we did see an added benefit of including that to some of the standard Maccabees. Now, there's a caveat to that. And that if you're dealing with smaller juvenile gophers, and you'll know that you're dealing with them, when you have tunnel systems that are smaller, if the trap won't completely slide down into that tunnel system without scraping the sides of that total system, then it's probably a juvenile gopher. And for those juvenile gophers, it was actually better to use the traps without that tether. The tether kind of gotten in the way of the jaws of those traps when you're dealing with a smaller tunnel system. So we would carry a combination of some of the Maccabees with the cable on it and some of the Maccabees without it. And we use the ones without the cable on the smaller tunnel systems and use the ones with the cable on it for those larger tunnel systems. And that seemed to work pretty well.
Farmer Fred 17:15
Now there is a fairly new trap out on the market. I don't think it's been subject to any UC trials. But it's called the Gopher Hawk. And from what I understand, there are a lot who are very happy with it.
Roger Baldwin 17:27
Yeah, so you're exactly right, there is a newer trap called the Gopher Hawk. It has not, to my knowledge, been tested yet, so I don't have any real potential feedback on it from that perspective, what I can tell you is that the trap design is as such to where when you find a tunnel system, you use part of the trap to poke a hole into that tunnel system. And then you insert the trap directly into that tunnel system so that it's vertical, sticking up. And when it's activated, there's a certain color and then when it's triggered, I think the yellow part of the trap shows up so you can basically walk around and scan your tracks from a distance and be able to tell if they're activated or not. And they're theoretically supposed to be a little bit quicker to set because all you have to do is poke a hole and then slide the trap down into it. So if they work, I think there is some potential advantages to them. They just haven't been tested. And so we're not really quite certain how they stack up to some of the pincher style traps yet.
Farmer Fred 18:26
I would think, too, that be it baits or traps, don't waste your time putting that bait or a trap down an old gopher mound. Look for the fresh mounds to indicate current activity.
Roger Baldwin 18:39
You are absolutely right. Regardless of the tool that you use, you always want to find the freshest mounding activity because that is going to be associated with a location where the gopher is still present. If you find old mounds that gopher may or may not still be in that part of the tunnel system. And if it's pretty old, they are pretty high that they actually are not in that part of the tunnel system anymore. So always be looking for that freshest mounding activity is the best strategy for getting whatever treatment approach you want to use to remove that gopher
Farmer Fred 19:13
Is there anything you wanted to add to this?
Roger Baldwin 19:15
The one thing that I would mention when it comes to gopher control is that you should consider utilizing an integrated approach. That means incorporating multiple strategies and there are a variety of different ways that this can be constructed. One example is using habitat modification. There are certain plants that gophers prefer and those plants are usually either nitrogen fixing plants or plants with large, fleshy taproots. So if you'd have come across a planting that have clovers and various legumes, or maybe have lots of nutsedge in and around some of these different cropping systems, you know, those are preferred food sources for gophers and so eliminating some of those preferred food sources can lower carrying capacity and, and that can lower the amount of effort it takes to manage pocket gopher populations in that area. When it comes to managing these gopher populations, what you really want to try to do is get those populations down to a very low level, and then maintain them at a low level. Don't allow those populations to build back up and knock them down again, because that's going to be more costly, long term. If you can maintain them at those low populations throughout the year, that's going to be much more effective and more cost effective for you as well.
Farmer Fred 20:30
Roger Baldwin, wildlife specialist with the Department of Wildlife, Fish and Conservation biology out of UC Davis, thanks for a few minutes of your time today.
Roger Baldwin 20:38
Absolutely, happy to help out.
Farmer Fred 20:42
Because there are so many demands on your time these days, I like to keep the Garden Basics podcast to under 30 minutes. Still, there is a lot more to tackle on all the garden subjects we bring up on the podcast. So, for that, and a lot more, we’re starting up The Garden Basics with Farmer Fred newsletter, on Substack. As the newsletter grows, so will the subject matter. So, yes, it will be a good supplement for the Garden Basics podcast, but there will be a lot more garden related material and probably pictures of my dogs and cats, as well. It’s the Garden Basics with Farmer Fred Newsletter on Substack. And best of all, it’s free! There’s a link in today’s show notes. Or, just go to substack.com, and do a search for Garden Basics with Farmer Fred. That’s substack.com. The Garden Basics with Farmer Fred newsletter. Did I tell you it’s free? It’s free.
Mary in VA 21:43
Hi, Farmer Fred, this is Mary. I garden in Arlington, Virginia, which is zone 7A. I'm a new gardener, I started gardening during the pandemic. My cucumbers looked so healthy and great. And then all of the sudden, they just start wilting. And then they completely die back. It'll take about a week or so. But like a whole plant will just suddenly wilt and die back and I know it's not water and I can't figure out why they're dying.
Farmer Fred 22:17
Well, that's a good question, Mary. Let's ask Debbie Flower, our favorite retired college horticultural professor and a licensed cucumber lover.
Debbie Flower 22:25
Yes, I run my own cucumber school. Yeah, I license myself.
Farmer Fred 22:31
All right, what causes cucumbers to croak?
Debbie Flower 22:33
Well, she says it's not water, all plants will wilt when they get not enough water. And they will wilt if they get too much. So I would want her to check that they're not drowning, number one, but she says it's a plant at a time. And that leads me to believe it is not what we would call environmental, meaning water, air, sun. Because I assume growing in a similar location and all experiencing similar conditions. But it's a plant at a time. I suspect it's bacterial disease that is brought to the plant by the cucumber beetle, both the spotted and the striped cucumber beetle can carry it. And it is a problem in that part of the country. And the Cooperative Extension in that region suggests applying pesticides to the plants, right as soon as they emerge. The cucumber beetles emerge in spring, and that's relative. Some springs are warmer earlier, some springs are warmer later. So they will come out from their dormancy. There's their winter sleep, when that temperatures are warm enough. And so that'll be a slightly different time every year. But when they come out, they are active for about six weeks, they chew into the plant. And if they have visited a plant with a bacterial disease, they can bring it to the next plant. And so they've injected it into the plant, it spreads throughout the vascular system or plumbing of the plant and it can kill them. A way to check for it is to cut a stem that is wilting is looking like it's gonna die and pull the pieces apart and then put them back together. So they touch and pull them apart. Maybe rub them a tiny bit, pull them apart. Again, if it has bacterial wilt, the bacterial wilt makes the sap sort of sticky. And when you go to pull it apart, you'll get strings of sap between the two pieces. That is a way to identify whether it is bacterial wilt or not. If you have it next year, you're going to want to look for cultivars that are resistant to bacterial wilt. And I don't have names of those off the top of my head. And then use a pesticide as a barrier on the plants when they first germinate. Up to six weeks.
Debbie Flower 24:45
Ppeaking of barriers, University of California Ag and Natural Resources agrees with you that control of cucumber beetles is difficult and that your general garden good guys can provide some control, but not total control. And their suggestion would be to use a row cloth in the early stages of the plant's growth to dissuade cucumber beetles from landing.
Debbie Flower 25:10
Excellent choice, better than the pesticides. Because like you said, the good guys have trouble, but they try. Yeah. And if you've put pesticide on the plant when they try, it's going to kill them. So if you cover the plant with a row cover, it would be a floating row cover not a frost cloth, not plastic. It's just a very thin fabric that you put down over the the plants just to physically keep the beetle from getting there and it's about six weeks in the spring that they are active. So depending on when you believe spring has really occurred, count six weeks and keep it covered for that amount of time.
Farmer Fred 25:45
You could do hoops as well.
Debbie Flower 25:46
You could do a hoop house. Yeah.
Farmer Fred 25:48
And that would allow the plant to grow some.
Debbie Flower 25:50
Yes, cucumbers, if they're happy, they can take off.
Farmer Fred 25:54
Yeah, so that would be unfortunately one of the few organic remedies for this.
Debbie Flower 26:01
Yes, for beetles in general. If you have a beetle problem. beetles in general are some of the most difficult ones to control.
Farmer Fred 26:08
Yeah, it's amazing. The good guys that will go after cucumber beetles. Green lace wings, damsel bugs, assassin bugs, Big Eyed bugs, minute pirate bugs, soldier beetles, ground beetles and spiders. But again, the cucumber beetles are faster, bigger, stronger.
Debbie Flower 26:25
They're pretty too.
Farmer Fred 26:27
Yeah, so a row cover. Might be your best bet there, Mary. Yeah, it's sad when a cucumber dies.
Debbie Flower 26:33
It is yes. I miss it.
Farmer Fred 26:34
I'm sorry to be a bummer. Yeah. Go have a drink. Debbie Flower Thanks for your help on this.
Debbie Flower 26:44
My pleasure.
Farmer Fred 26:46
The Garden Basics with Farmer Fred podcast has a lot of information posted at each episode: transcripts, links to any products or books mentioned during the show. Plus, you can listen to just the portions of the show that interest you, it’s been divided into easily accessible chapters. There’s other helpful links for even more information, including the new Garden Basics newsletter. And just like the podcast, it’s free. Plus you’ll find more information about how to get in touch with us. Leave an audio question without making a phone call via Speakpipe, at speak pipe dot com slash gardenbasics. it’s easy, give it a try. And you just might hear your voice on the Garden Basics podcast! You can also use your phone to call or Text us the question and pictures, 916-292-8964.916-292-8964. E-mail: fred@farmerfred.com . If you tell us where you’re from, that will help us greatly to accurately answer your garden questions. Because all gardening is local. In the show notes you’ll find links to all our social media outlets, including facebook, instagram, twitter, and youtube. Also, there’s a link to the farmerfred.com website. And if you would please, if you hear something you like, share it with your friends and family. Thank you!
Farmer Fred 28:11
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