S5 Ep 6: Protecting Hawaii’s Farms From High-Risk Invaders

Jamie Miller from OISC explains why early detection beats eradication and how biocontrol could change the game. We learn about practical ways to protect Hawaii’s ranches and farms from devilweed on Oahu and the two-line spittlebug on Hawaiʻi Island, with clear ID tips, reporting tools, and prevention steps. Visit OISC website at https://www.oahuisc.org/ for more information!

• Defining invasive species and why funding targets early-stage threats
• Devilweed ID features and fire risk profile
• Toxicity to livestock and impacts on pasture recovery
• Oahu hotspots, trail work, and volunteer efforts
• Management shift from eradication to mitigation
• Seasonal timing for removal and safe disposal
• Decontamination for gear, trailers, boots, and feed
• Reporting routes via 643pest.org and OISC resources
• Two-line spittlebug signs, grass losses, and replacement by weeds
• Apps, documentaries, and mapping to support response

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Transcript

Show Intro And Today’s Focus

SPEAKER_01 0:15

Aloha! Today's episode is sponsored by the Livestock Extension Group of the University of Hawaii, Manoa College of Tropical Agriculture and Human Resilience, the Center for Ag Profitability out of the University of Nebraska, Lincoln.

Guest Introduction: Oahu ISC

SPEAKER_00 0:27

Aloha and welcome to the Livestock Fala O, a podcast aimed to provide educational support, information, guidance, and outreach to our livestock stakeholders in Hawaii and the rest of the U.S. We are your hosts, Meleo Shiro and Shannon Sand. And today we're going to be talking about protecting Hawaii's farms and ranches from invasive species, focusing on some things such as devil weed and other high-risk invaders, um, with our guest, Jamie Miller from Oahu Invasive Species Committee. Thank you, Jamie, for joining us today. Yes, thanks so much for having me. Yeah. I think maybe we'll just start a little um by if you want to introduce yourself and sort of what your role is with um Oahu Invasive Species Committee. Or um, I know Big Island is BISC, is Oahu ISC? How do we shorten it? We call ourselves OISC. OISK. Okay.

unknown 1:17

Yeah.

What Makes A Species Invasive

SPEAKER_03 1:18

Yeah, thank you so much. My name is, as you said, Jamie Miller, and I'm the outreach and education associate with the Oahu Invasive Species Committee. So our goal over at OISC is really to protect Oahu's native ecosystems, agriculture production, and even the public's quality of life by eradicating um high what we call incipient or highly invasive invasive uh species and contain really um some of these high impact invaders.

SPEAKER_01 1:48

Cool.

SPEAKER_00 1:50

Yeah. So I know there's different uh sort of species that are probably higher invaders on some islands, but you know, we want to, I guess we'll just talk about what we consider as an invasive species, right? And why is that important for us to know sort of what is an invasive species is?

SPEAKER_03 2:08

Yeah, so an invasive species is defined as any non-native species, which is something that was introduced to Hawaii by people, that causes us some kind of harm, either harm to our public health, it could be harm to our environment, our economy, or even our quality of life. So that's a really broad definition. Some invasive species impact in maybe just one way, other ones are really bad and could impact us in all of those ways. So at the invasive species committees, we focus on ones that are some of the worst of the worst. So they might impact us in a lot of different ways. And when I say incipient, what I mean is something that's more newly introduced. So when we focus on an invasive species, we want to make sure that we have a good chance of eradicating it or having a big impact on it. Um, because, or else we don't have enough funding. We could, you know, work all day on all the really bad invasive species out there.

SPEAKER_01 3:11

There's so many invasive species on the islands that it's yeah.

Why Economics And Eradication Strategy Matter

SPEAKER_03 3:16

Yeah, exactly. So we want to make sure that we're having an impact with the funding that we do have on those invasive species.

Devilweed Overview And Risks To Ranchers

SPEAKER_00 3:23

Yeah. Well, and I think you made you said a good point about the economic impact that these species have, right? Whether it's the threat to our agriculture that's here, you know, we've seen that in some of the ranching communities with some of the invasives that have come through the economic impacts and making those connections. It's hard, but it's definitely there. And I think some of the big parts of, you know, why we need to do what we do and helping to control these things, right? And I think um, so I know there's many different invasive uses, and we could talk, like even we we were talking the other day with Franny, there's so many different species out there, right, that um do have an impact on agriculture and the level in which they impact them, you know, is different. Um, but can you you want to talk maybe about one of the ones that we were talking a little bit more on Oahu and one that illustrates these issues for um kind of our ranchers and farmers, right? Is devilweed.

SPEAKER_03 4:16

Correct. Yeah. So uh one of OSK's what we call our target species is devilweed. And Devilweed is one of our species that does have a high impact on farmers and ranchers, and that's because it can be very toxic to livestock and difficult to manage once it gets into pasture lands. So we really want to prevent this plant from getting into farmers and ranchers' pasture lands because we don't want to see those impacts in the livestock. It's also a high fire risk. So this plant has a very high oil content and it tends to um appear very dry, even when it's well watered, it has this very limp appearance, um, which causes it to catch fire pretty easily. We've also seen in areas where there was a fire that it tends to be the first thing to sprout after, giving it an even better chance at taking hold. So those are the biggest concerns for uh farmers and ranchers on why we want to um get rid of this plant. But I can tell you a little bit more about it um so people know what to look out for.

How To Identify Devilweed

SPEAKER_01 5:24

Yeah, that would be good. Yes, please do.

SPEAKER_03 5:26

So devilweed is the characteristics of it and the way it even gets its name is from its leaf. So its leaf is a triangle-shaped leaf with toothed edges and then a devil's pitchfork veination. So that devil's pitchfork in the middle um of the plant really um is where its name comes from. As I mentioned, the leaves often look limp when you see it. And then if you actually crush one of the leaves, you'll get kind of a turpentine own from it. So you can kind of smell that like high oil content. Or even if you're working around a lot of it, you'll start to smell, smell it. And if you're working around a lot of it, it's known to be um a little bit of a respiratory irritant as well. So one, you know, work being around a plant or two isn't um too bad, but if you're around a lot of it all the time, um if the plant matures really fast and produces a lot of seeds, so you're looking at about six months um before it can mature. And then when it produces seeds, it's about 800,000 seeds a year from one plant. Wow, that's a lot, right?

SPEAKER_01 6:33

It's like that. I feel like that's a lot of seeds.

SPEAKER_00 6:35

That's scary. Yeah, but it's kind of I mean, in the way it the the amount of seed that it puts out. I mean, it reminds me of the yellow flower, right? And fireweed on the big iron where it kind of just can take off and come in.

SPEAKER_03 6:49

So devilweed is in the Asteraceae family, so that's the same thing as dandelions. So you can picture when the after um the flowers bloom, which is um in around December to February, so it's coming up soon where this plant will start flowering. After it flowers, that flower will turn into like a dandelion-like puff with all these seeds that is very easily wind dispersed. So when the wind blows, those seeds are getting out into the wind column and spreading all over. Another thing, when they're wet, they act kind of like velcro. So that soft um material on the seed is really easy to stick to.

SPEAKER_01 7:28

I was gonna say it's sticky. Yeah, it's one of those, yeah.

Spread Pathways And First Detections

SPEAKER_03 7:32

Yeah, yeah. So um, where it was actually first discovered on Oahu was the Kahuku training area. So that area also doubles as a motocross track. So we have um this area with really um a high risk area for attraction introduced, yeah. Yeah, and so since then we've seen it pop up in several other locations where there's larger populations, and then even sometimes we'll see it pop up in a really random place, like on a beach access, and that's because of that how easy it is for it to attach to someone and end up being distributed somewhere else. So where where did Devilweed originate from? Do you know?

SPEAKER_00 8:16

That's a good question.

SPEAKER_03 8:17

Yeah, so uh devilweed has a a pretty large native range, it's native to the southeastern United States, even Florida and Texas. So very, very I know.

SPEAKER_01 8:28

I was like, you're describing this. I'm like, I'm pretty sure I've gone through fields at home. I'm from North Florida, and I'm like, I was like, I'm pretty sure I've seen this boy.

SPEAKER_03 8:37

Yeah, and then also Mexico, Central America, South America, and the Caribbean. So um, but we we see it used in other places as well. It it's one of the world's top 100 invasive species, so we see it popping up in in other countries, even um countries like Africa, and sometimes we even have people that'll reach out from there, farmers from there that need help with managing this plant as well. And especially if you don't have um it a lot of access to resources, we've just heard how time consuming it can be to try to physically remove this plant. Um, so it's something that is you know better prevented before it's introduced.

SPEAKER_00 9:19

Well, I think you led us into what I was gonna ask you, Ness, was sort of what is the treatment for it or what kind of response and are you folks working on to help sort of, you know, we always we want to always want to have an idea that we can get rid of something, not that we always can, but um, what what's your folks' um sort of response to this speech invasive species now?

Origins And Global Invasion Status

Management Shift And Biocontrol Plans

SPEAKER_03 9:40

Yeah, so when it was first introduced in uh 2011, ourselves and Army Natural Resources Oahu program were very adamant about eradicating this plant. Um, so we were working really hard to remove it in that area. And um, unfortunately, over time, we started to see it very quickly spreading to new locations and even some locations that we're not going to be able to access or manage. So at that point, we realized eradication was not possible for Oahu. So, right now, our goal is to uh mitigate the effects by really reducing populations in important areas. We reach out to farmers and ranchers, so that's a big part of what we've been doing this year is trying with Chromalina is trying to reach out to ranchers and farmers on the North Shore area where this plant is very prevalent, in order to provide them with resources so they know what to look out for and know how to manage it if it shows up. Now, and all of this is um buying time until a biocontrol can be introduced, which would be the next step in managing it, is um currently one of the biocontrol um projects that's ongoing is a um pest for devil weed that would help to bring down those populations and especially in the large infestation areas.

SPEAKER_00 10:59

Yeah, because I can imagine, I mean, with any other weed species, if they get out into those bigger pasture grazing lands, I mean it's hard to get you know a sprayer in there, tractors or mechanical um equipment in there to help remove that. So yeah, I think yeah, that's having something like that. And that's I mean, that was my other question was is there any biocontrols that they're looking at? So good. I'm glad. Yeah, and then go ahead.

Oahu Hotspots And Volunteer Efforts

SPEAKER_03 11:24

I was gonna tell you, um, particularly with devil wheat, it was a cliff side where it was showing up, and so this cliff side that really was inaccessible, and the only way to treat it would be um via helicopter herbicide by by helicopter. So that wasn't able to get off the ground, so yeah.

SPEAKER_01 11:43

So, where all has devil weed been detected in Oahu? And again, because just because I I'm trying to make a sticky symbol with my hands, but because it is such a sticky plant, is it on the other islands yet, or is it has it been detected anywhere else on the islands that you know of?

SPEAKER_03 12:00

So, unfortunately, in 2021, it was detected on Big Island. So um, the Big Island invasive species has been working um to control it in um the Pune district, and um they're working to still eradicate it from the island. So on Oahu, we've seen it pop up in large populations in Aia, in uh Pupukea, we have it in Kahana on the North Shore area, and then also um Waimanalo as well. We actually take volunteers up into the Pupukea Forest Reserve once a month, and we do a volunteer trip. This area has a lot of mountain biking trails, so not only do we have hikers, we have mountain bikers that we want to try to get it off the trail just so it doesn't continue to get spread um quickly. Yeah, yeah.

Producer Actions: Survey, Remove, Report

SPEAKER_00 12:50

Yeah, and you know, you talked a little bit how it spreads. I mean, it's it's scary in a sense because it is a it's an easy spreader, right? With having the the seeds the way it is, and um what so what can we tell our producers and if they have it on their operation? I mean, really that's what we want to know is what do they do, right? And how what why is this important for them and how should they respond, I guess, in a sense, if they do find it on their property.

SPEAKER_03 13:17

Yes. So we actually recommend that farmers and ranchers be on the lookout for this pest. Um survey areas every three to six months to see to make sure that if there's a presence of it. If you find the plant, you can remove it and put it not into the green waste. We want you to put it into the trash, right? So that it doesn't continue to spread. Um, removing plants at this time of year before they start to mature is is important. So uh I think if you're planning on doing, um, let's say you're planning on surveying for it, you want to do it now before it starts flowering and then seeding, because the flowering season again is from December to February. And then there's even um scent detection dog services available. Um that's through, I believe, the Conservation Dogs of Hawaii.

SPEAKER_02 14:10

Yeah.

SPEAKER_03 14:11

We have a lot of great resources on our website. So if you go to um our website, we have a handbook for farmers and ranchers that's specifically geared towards them so that they're able to um learn more about the plant, how to detect it, and then even how to control it. Um, we have recommendations for um herbicide as well.

Toxicity To Livestock And Pasture Impacts

SPEAKER_00 14:33

Yeah, and the the foliage I know is pretty toxic to um livestock, right?

SPEAKER_03 14:38

And can have some respiratory and even I think skin sort of allergic reactions in a sense to that, like toxic it has a really high night nitrate, nitrate content, um, and that causes them to get ill over time after they're eating it for uh longer periods of time.

SPEAKER_00 14:57

I I believe it's sort of a more of a chronic issue, kind of similar in a sense of to fireweed, and in a sense that how it impacts those those major organs. So um it is something to definitely think about with our producers that you do want to be able to have that. And I think the scary part is that it's a weed and those are what comes in every time when we have impacts into the grazing species that are desirable in there. Um, these weeds are what come up, right? So um I think it's important for us to make sure we know how to properly identify them, right?

SPEAKER_01 15:28

And um yeah, you especially if it impacts cattle and is gonna Yeah.

Reporting Tools And OISC Resources

SPEAKER_00 15:34

And I really want to say, like with livestock, typically it's the younger spe the younger um stock that will have a higher impact to them, right? Because they just can't handle those higher levels as as the older animals can, and usually that's where you see some of the signs. So um, so where do our farmers or ranchers go if they find um something? And is there a way for them to report these in case it's not an area that um was previous previously identified with Devilween? Yes, um they can.

SPEAKER_03 16:05

So what you can do is you can report any invasive species anywhere in the state of Hawaii to 643pest.org. So we recommend reporting it there. Even though it's on Oahu, it's known to be island wide. We still recommend that people report it just so we know where it's moving. And that's especially important when it comes to that biocontrol because we want to know where it's at so that when the biocontrol is released, they're able to bring it to those areas. So you can report it through 643pest.org. Up that website will get it out to the right agency. For example, you report devilweed on Oahu, it's gonna go to us at OISC, and then we can provide you with more resources. Also, our website, awahuisc.org, has some great resources for Devilweed. If you go and um look at our uh resources tab, we have a farmer and ranchers handbook that's specifically geared towards devilweed as well.

SPEAKER_00 17:09

Oh, perfect. That's that's great. So what else? I mean, our farmers and ranchers um not just identifying them, I think is an important part, right? Knowing what they're looking for, but uh what else sort of information can they gather from out there to make sure um, you know, if they're they want to make sure that's a proper identification for that, as well as like what else can they do to ensure the stopping or slowing the spread of this plant around the island?

SPEAKER_03 17:36

I think really just keeping an eye out and then being careful when it comes to decontamination. So, for example, um, as your uh cleaning equipment between pastures to make sure that you're not introducing um weeds from one pasture to the next, you checking your cattle trailers and your um even feed that's come feed shipments that are coming in, uh monitoring the fence lines and disturbed areas. So disturbed areas are where this plant is going to be introduced to first. Um, so those types of areas, keeping a close eye on them to ensure that nothing is getting uh introduced that way. And we also encourage hikers to do the same, right? So just like um farmers and ranchers, we always encourage hikers to make sure they're cleaning their boots in between hikes so that they're not transferring any of the seeds with them.

Two-Line Spittlebug Threat On Hawaiʻi Island

SPEAKER_00 18:29

Yeah. Yes, and I encourage our hunters as well to do the same because they go into a lot of those same areas, you know, and um just you know, being a good, good, good um, what do you call citizen in our community. Or it's gonna say steward of the land or whatever. Steward of the land to, you know, try to prevent these spread of these things. So um we have so devil wheat is a big one, I think, that I don't believe we talk about enough because it was, I think, at one of our meetings in Oahu that I I don't remember if it was you, Jamie, or someone else from your committee that um we started talking about this and um realizing you know how much it had spread over Oahu and it's um coming onto the big island. So we have other invasive species as well, unfortunately, that impact, but we want to talk a little bit, I think, on Hawaii Island um about the two-line spittle bug.

Containment, Apps, And Movement Risks

SPEAKER_03 19:19

Yeah, so over on Big Island, farmers and ranchers also have to worry about the two-line spittle bug. Um, it's always good to talk about invasive species that are happening elsewhere, too, because you could be next for those. So it's good to know what's out there because preventing andor detecting something early is the best way to catch an invasive species. Um, on what the two-line spittle bug is is a very, very small black leaf hopper, and it has these characteristic two orange, orangish red stripes. So it's only about a centimeter long, so you can imagine that's pretty tiny. Um, and it was first detected on Big Island in 2016 and quickly started spreading through the west side of the island. Um, it caused the loss of thousands of acres of uh Kikuyu grass and Pangola grass pastures, and unfortunately, those past pastures tend to not recover. So instead, it's replaced by other invasives like fireweed, pumicani, and blackberry. People can look out for presence of the two-line spittle bug by looking for patches of unexplained dead grass, and you'll see these spittle masses at the soil line. So, our recommendation is to keep an eye out for that. And you can again report it to 643pest.org, especially if it's seen out of the Kona area. Um, there's also a great documentary that BISC has on their website or on YouTube. If you look up um the two-line spittlebug documentary, uh A New Threat to Hawaii's agriculture. It's a really great um documentary to get educated on it as well.

SPEAKER_00 21:07

Yeah, there's also an app that Dr. Mark Thorne um had done and put together as well that you can use to um report any suspected areas that are impacted by two-line spittlebug on the big island. And I think, you know, um the other, you know, you make a good point about us being good stewards of the land when we're going through everywhere because we did have a couple of um uh sort of isolated um populations pop up on the big island. Uh, a lot of times those things come from movement of whether it's soil matter or um equipment, maybe, you know, and the hoppers, the bugs are are pretty good hoppers. I mean, they'll if you shake things out before you get in your trucks and things or trailers, um, you know, anything you throw in the ground in an area that you know has spittle bug, I mean, they'll pretty pretty good about hopping out, but um, getting them in the the eggs in the soil um in manure or things. Things like that, and getting in a trailer and then moving animals around. I think that's one big concern. I think that we've talked about. Um, so you know, making sure if you're gonna take your horses to another property that doesn't have spittle bug and you are in an area that does, um, cleaning out your horse's hoops before you leave, um, trying to make sure your trailers are clean before you get I I know it's an extra step, sometimes not always doable and takes in a few extra minutes or uh extra time out of the day to do, but I think um it's important to think about when they're uh moving animals around.

Early Detection Beats Eradication

SPEAKER_03 22:32

And I think Yeah, that's such a good point because honestly, I mean, it might be an extra step and that might not seem doable, but it's gonna prevent you from other extra steps in the long run. So I think it's really important to you know take um decontamination seriously and um put put forth uh effort into it so that you can prevent a future invasion.

Final Resources, Social, And Closing

SPEAKER_00 22:53

Yeah, yeah. And I that's exactly the early detection, right? And prevention is really um easier than the eradication on the end of it, right? Exactly, yeah. But yeah. Well, thank you, Jamie. Is there anything else you'd like to share with us or any other um things that we can think about or do, or any other species we should be concerned about? I mean, I know there's a lot out there, but is there anything else you want to share?

SPEAKER_03 23:17

Those are the most important ones that we have to talk about with farmers and ranchers. Um, but just remember you can always report any invasive species with 643pest.org. I always say, even if you see something and you don't know what it is, like it's just weird, or you're like, hey, I've never seen that bug before. Just go ahead and report it because they they don't receive like an overwhelming report where they're not going to get to it, right? So that we'd rather have you report it than um it go get missed. Yeah. And then you can always stay connected with us on social media. Um, our handle is at Oahu ISC and our website, oahuisc.org, has a lot of great resources for invasive species as well.

SPEAKER_00 23:59

Great. Thank you so much, Jamie, for joining us today. Yeah, thank you so much for having me. This is great.

SPEAKER_01 24:06

Yeah. That's awesome. Yeah. Make sure to follow us on our social media pages, the Livestock Vala Out and the Livestock Extension group if you haven't already. Be sure to visit the UHC Tar extension website and our YouTube channel listed in the show notes.

SPEAKER_00 24:18

Yes, for additional information about this or other topics or comments, send us an email at Vala Ow at Hawai'i.edu. And thanks again for listening to the Livestock Vallal.

SPEAKER_01 24:27

Yep, yep. Before we go, show some love for your favorite podcast by leaving us a review wherever you're listening to this. And then stay tuned for next month's episode.

SPEAKER_00 24:34

Thanks again to our sponsors, the Livestock Extension Group of the University of Hawai'i Manoa College of Tropical Agriculture and Human Resilience, the Center for Ag Profitability of the University of Nebraska Lincoln, and the Western Sustainable Agriculture Research and Education Program. Mahalo for listening. Awesigo. Awejo. Thank you.