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Kudzu bug

 
Mike Turner
Posts: 309
Location: Upstate SC
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This new invader from Asia, Megacopta cribraria, also known as "globular stink bugs"  made its landfall near Athens, GA in 2009 and is spreading out rapidly from there (its a strong flyer).  It showed up in my garden this summer, where it is devastating my pole beans (especially the purple podded ones) and has appeared on my yard long bean and cowpeas in lesser numbers.  There are 100's of them on every pole bean plant and I can go out every morning, knock them all into a pan of water to drown them, and the next morning there will be just as many replacements to go out and drown.  They release a stink and your fingers get stained yellow from knocking them off the plants.  Like the Japanese beetle, it is a congregator and homes in on sites that has their smell.  But on the positive side, you won't find any Japanese beetles on the bean plants that they have infested.  This bug sucks sap from kudzu, soybean, pole/bush bean, yard long bean, cowpeas, lablab bean,fava bean, potato, citrus, and a number of other plants.  Around here they can build up their numbers to astronomical levels on the local kudzu, then heigh on over to my pole, cow, and yard long beans to continue their feast.  Then in the fall they try to invade your house to spend the winter.  Don't know of any native predators that will touch them.  Hopefully their numbers will settle down following their initial invasion, but if this keeps up the only way I will be able to grow beans sans insecticides would be to grow them under a high tunnel cold frame covered with insect barrier cloth.

 
Jeanine Gurley Jacildone
pollinator
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Location: Midlands, South Carolina Zone 7b/8a
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I'll have to look a little closer here.  I have not had too many japanese beetles this year but something, I thought is was our usual stink bug, just sucked the life out of my blackberries, my neighbors too.

I looked on line at the name you gave, seems fairly distintive looking but I can't tell the size.  Is it about the same size as the usual stink bug?
 
Mike Turner
Posts: 309
Location: Upstate SC
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Its smaller than the usual stinkbug and when you first see it, you'd think it was a small beetle, but it is a true bug of a shape that isn't native to the New World.  It is about the size of a small dried pea (3-4mm or 1/4".  The range maps show it getting as far of Columbia, SC last year.  At the rate it is spreading you'll probably see it in your region late this year or next year.
 
Mike Turner
Posts: 309
Location: Upstate SC
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Since this bug is attracted to sites that carry its stink, I tried adapting a Japanese beetle trap to catch them by seeding the trap bag with a few dozen kudzu bugs.  But it didn't work since they had no problem climbing out of the bag.  They also have no problem climbing up the walls of a stainless steel water bucket (have to add soap to the water to kill them).  So far, they haven't found some volunteer pole beans that popped up near the house, so it looks like if you can detect and kill the first bugs that show up on your plants before they can leave their smell on the plants to attract the rest of the horde you might be able to keep them at bay. 

Kudzu bug isn't a good common name for this bug since it feeds on a lot of plants that are more economically important than kudzu.  I refer to them privately as "the devil's pellets" as they rain down on me whenever I brush the bean stems and petioles they are clustered on when it is too cool for them to fly in the early morning.  After it warms up, I am assaulted by a myriad of flying projectiles when I brush a bean stem.  Add their persistent stink and yellow stain (won't wash off with soap and water) and their debilitating and killing effects on bean plants and that is a good name for them. 

I noticed that a 5 acre field of commercially grown pole beans along my driving route was recently plowed under.  Normally they keep harvesting until close to first frost.  A victim of the kudzu bug?
 
Jonathan Byron
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Preliminary laboratory bioassays of {the microscopic fungi} Beauveria bassiana and Metarhizium anisopliae against field-collected Megacopta cribraria adults dipped in spore suspensions showed both fungi caused 100% mortality at concentrations as low as 9 conidia/1000 mL. Adults killed by Beauveria bassiana were collected from naturally-infested kudzu in Oconee Co., GA. Surveys confirmed the spread of Megacopta into 71 Georgia counties since its accidental introduction into Georgia in 2009.


http://www.reeis.usda.gov/web/crisprojectpages/208212.html


Beauveria bassiana spores are sold under the name Mycotrol. Not cheap, around $90 a quart, I believe. That product also controls many other pesky insects (including ticks), not sure how it affects beneficial insects.
 
Mike Turner
Posts: 309
Location: Upstate SC
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That could help. but if it takes a day or two to infect and kill a bug, then  its not going to be able to help much.  Kind of like trying to use pesticides to protect your crop against an invasion of migratory locusts.  Even if kills the insect after it takes one bite, they are coming in by the millions, and that one bite times a million totally wipes out your crop.  The problem with kudzu bugs is that they are breeding on the many acres of kudzu in the region and then spill over into your garden and onto your beans.  I've seen no eggs or nymphs on my beans since I clear the adults off each morning, but they keep flying in each day in numbers enough to wipe out your bean production and eventually to kill your plants.  Haven't seen any predators going after them.  Even the wasps and fire ants attracted to the nectaries on the yard long beans and cowpeas ignore the kudzu bugs,  I've read they also go after english peas and favs beans, so I'll have to see how bad they are on those crops this spring.  They won't be breeding on the kudzu in the early spring, so it will just be the overwintering adults that I'll have to contend with.  But it looks like the only way they I will going to be able to grow beans in the summer is going to be by excluding them with an insect barrier floating row or high tunnel. The old days of easy bean cultivation and just worrying about picking a few dozen bean beetles and at the worst, some Japanese beetle damage, is over.
 
Jonathan Byron
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If you are experiencing a 'plague of locusts' situation, then you might have to turn to pyrethrin or other botanical knock-down agents, or neem or other repellants.

Eventually, the biocontrol fungi should establish themselves and lead to an equilibrium with the pest, but that might be after a few lost harvests if there is currently an unstable situation from a new insect.
 
Mike Turner
Posts: 309
Location: Upstate SC
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The Kudzu bugs have been just as bad this summer as they were last summer, with hundreds of them covering the stems and petioles of the pole beans, soybeans, cow peas, and yard long beans. So far, they haven't bothered my peas, fava beans, or figs. This year, instead of the usual bean trellis row, I tried dispersing my bean plants around the garden growing them in groups of 3 growing up tipis or single poles, but the bugs found them anyway. The bug's feeding drastically reduces the bean harvest and eventually kills the plant. The bugs themselves are nasty to deal with as they give off a noxious stink when you disturb them as you brush the foliage in the process of bean picking, they leave a yellow stain on your skin, and they get all over you as they fly away from the parts of the plant that you disturb. The harvested beans come into the house stinking of kudzu bug. So beans have been transformed from the important part of the summer harvest that they were in the past to an iffy producer of small numbers of pods. Since these bugs are here to stay, next year I'll have to try growing them in a cold frame under insect screen cloth or give up on summer bean growing altogether.
 
Mike Turner
Posts: 309
Location: Upstate SC
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This spring the kudzu bugs appeared by the 10,000's on my green manure crop of Banner fava beans turning their stems black with congregating bugs. So far they haven't attacked any of my Broad Windsor fava beans or the pea beds nearby, but they have appeared in low numbers on my groundnuts (Apios). I scythed the the Banners down (a premature harvest) yesterday and am waiting for the bugs (and their stink) to disperse before planting sweet potato in those beds. Since the kudzu bugs first arrived 2 years ago, I haven't been able to harvest more than a a few handfuls of pole or asparagus beans out of my garden and haven't even attempted to grow edamame soybeans. This year I plan some experimental plantings of pole and asparagus beans to see if a mulch of coffee grounds and/or a spray of coffee grounds "sun tea" will help repel them.
 
Bob Dobbs
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I wouldn't necessarily worry too much about the sweet potatoes, kudzu bugs are quite specific to legumes. I've been watching them since about 2009-10. I do know that wisteria sinensis is a decent catch crop (finally, a use for wisteria sinensis!). The kudzu bugs do sit on other types of plants, actually most types of plants, but close observation shows that no damage occurs on non-legumes.

I'm still not sure what would be a good holistic-type cure for these guys.
 
Mike Turner
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Location: Upstate SC
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Progress report. So far, the experiment with coffee grounds mulch has been a great success. I started with 2 mass plantings (a 7 pole teepee) and 2 plantings of a single plant growing up a bamboo pole. One set (teepee and pole) I mulched with coffee grounds as the bean (pole and yard long) seedlings were just starting to emerge. The other set I grew as I used to grow beans in the pre-kudzu bug era. I have yet to see a kudzu bug on the coffee grounds treated plants. When the non-treated plants got about 4-5 feet high, I started seeing a few kudzu bugs appear on the plants. These bugs are aggregators and normally once you see a few appear on your beans, within a week their stems and petioles will be covered with dozens to 100's of them. You can shake the plants to get them to fly off, but within a few hours they will all be back on the plants. On the non-treated plants, once I saw the bugs appear (about 3 to 5 bugs) I mulched the ground under the plants with coffee grounds and disturbed the plants to make the existing bugs fly off. Since then I've just seen a few bugs occasionally reappear on these plants and it has been very easy to disturb them to get them to go elsewhere. This is the first time in the past 3 years that I am actually getting a normal bean harvest and have been encouraged enough to just now plant a trellis of pole beans like I used to do before the kudzu bug arrived on the scene on 2010. It will be interesting to see if the coffee grounds also repels japanese and bean beetles (so far none of either beetle on the plants despite the start of the japanese beetle season and their increasing presence on other plants).
 
John Elliott
pollinator
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I've had them sporadically here in Augusta. They seemed to like to congregate on the crimson clover I have for green manure, but have not been much of a pest otherwise.

I'm trying an experiment to see if I can isolate a natural cure. I've taken a plastic pill bottle, drilled 1.5 mm holes about a half inch up from the bottom all the way around, and put some bugs in to die. I buried the bottle most of the way into the ground and covered it with leaf mulch, hoping that some nematodes will come exploring and find the kudzu bugs to chew on. Or maybe some fungal hyphae. I'm not particularly concerned about what kills and eats the bugs, just that their natural recyclers get a chance to go to work. The bottle has been in the ground for a couple of weeks, so in the next few days, I need to dig it out, look for gross disgusting putrefied bug carcasses, and reculture that onto a fresh crop of bugs.

Anyone else in the area want to swap stories and techniques?
 
I agree. Here's the link: http://richsoil.com/cards
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