Mary's Veggie Garden

September 11, 2012

Edamame Harvest Disaster

Filed under: Beans,Edamame,Gardening,Insects,Mexican Bean Beetle,Pests,Stink Bugs,Vegetables — marysveggiegarden @ 7:44 am

Usually the soy bean harvest is a time of contentment and of rewarding, hard work. This year it is devastating.

The harvest process goes like this: Click here for a look at last year’s harvest.

  • Lop off the bushy plants at their base.
  • Snip off the lush, green foliage to reveal the branching stems crowded with pods. Return the foliage to the garden as mulch.
  • Pull off the pods, each bulging with 2-3 full-sized beans.
  • Fill a couple of plastic grocery bags with pods for the bicycle trip home from the community garden.
  • Steam the pods for 6-7 minutes, then cool quickly in cold water, then shell.
  • Repeat for 4 days, until the harvest is finished.

The family shelling party is a chance to chat, as we fill bowls with the perfect,bright green edamame beans.

The story is very different this year. (Click on any picture to enlarge.)

There is no lush green foliage. Most of the leaves are completely skeletonized by Mexican bean beetles. The few remaining green leaves have several bean beetle larvae feeding or metamorphosing on the their undersides.

Mexican bean beetle larvae on edamame soy. The larvae with white noses are the older ones, metamorphosing into adults.

Mexican bean beetles prefer common green beans and their close relatives (Phaseolus vulgaris) but if they can’t get green beans they will switch to soy (Glycine max). After killing all the green bean plants in the area the beetles attacked my soy at mid-summer when the plants were big and bushy.

Soy plants with whole branches of flat pods and leaves skeletonized & killed by Mexican bean beetles.

As usual, pods crowd the edamame stems. But this year about a third of them are flat, with only the merest hint of a bean inside. Another third contain small, very underdeveloped beans. And a third have full-sized beans. I attribute the flat pods and tiny beans to defoliation – it is difficult to grow full-sized fruit with almost no leaves. I’ve been growing edamame soy at the Vassar Farm community gardens since 2005 and this is first time I’ve lost a crop to bean beetles.

So I filled a single bag with full and undersized pods. It was very light-weight.

2012 Soy harvest

Last night I steamed the pods then we shelled out the beans. Instead of perfect green beans, they have brown spots and sunken areas. About half of the full-sized beans are damaged along with 90% of the underdeveloped beans.  And some of the beans in the OK pile have suspicious tan areas I don’t recall ever seeing before. The pods themselves look fine, with no hint of the damage waiting inside.

Stink bug feeding damage on edamame soy beans.

I’m attributing this damage to stink bugs. They seem to have these micro-fine stiletto mouth parts they can insert into fruits and vegetables (apples, tomatoes, peppers) without visible damage to the skin. During harvest I’ve found  both green stink bugs and brown marmorated stink-bugs, both nymphs and adults. I’ve squashed more than a dozen. (It took 5 minutes to collect the bugs in this picture from an asparagus planting in a local public garden. Photography took considerably longer, the things won’t stand still.)

Green stink bugs and brown marmorated stink bugs, both nymphs and adults.

I read some research from Ohio State University. Stink bugs feed by injecting saliva into the fruit, then sucking out the pre-digested contents. The digestive enzymes stop development of the fruit, leaving corky areas. So it is possible the stink-bugs have caused a lot of the under-developed beans. Although it is possible to cut stink bug damage out of a tomato, the damage fills most of a soybean so I’m discarding damaged beans.

Now, after harvesting three-quarters of the soy bean patch, yield is about 20% of normal.

Our conversation while shelling the beans got rather dismal. The brown marmorated stink bugs are invasive. In the last few years they’ve spread rapidly up the east coast. And according to Rutgers there are no good controls. On our trip across NYS last week we passed hundreds of acres of soy beans and apples, two crops by brown marmorated stink bugs. And there is drought through-out the grain belt. Is the time coming when the US will be unable to feed itself, never mind feeding Africa?


  1. I am so sorry to hear about your soy beans. Those nasty stink bugs. Did a great job with that last photo.

    Comment by Norma Chang — September 11, 2012 @ 7:58 am | Reply

  2. I am so sorry to see the damages on the soy! But thank you for posting this. I was wondering what ate all of the foliage on my hard bean plants in just 2 days! I grew a bit of soy beans myself and my first crop that I harvested in mid July was successful. The second crop that I harvested a few weeks ago – no so much. I was amazed of the difference. The Japanese beetles also did some damage to the leaves. The stink bugs? Yes, they are absolutely on everything in the garden, not to mention the outside of every window of the house. Do we have to start covering up the entire garden to avoid all these problems?

    Comment by TS — September 11, 2012 @ 8:30 am | Reply

    • The bean beetles hide out on the underside of the leaves, so often they are not noticed until damage is severe. Some years Japanese beetles can do a job on soy beans, but at least they are on to where they can be seen.

      Next year my soy beans will be under a floating row cover from the time I plant. I’ve heard of people covering the entire garden, and I’ve seen vast row covers 50’x100′ at CSAs protecting against flea beetles on brassicas. I’m reluctant to cover everything because diseases flourish in increased humidity. Also it’s difficult to manage a crop under cover.

      Comment by marysveggiegarden — September 11, 2012 @ 8:55 am | Reply

  3. Too bad about your poor edamame crop! – especaiily since you were planing on enjoying them all winter long. Your descriptions and photos were quite helpful – I’ve been seeing more of the stink bugs around my garden/yard this year; guess their numbers our definitely on the rise in our county. Scary to think that all of these bugs and bad weather conditions, etc. are negatively impacting the yields in so many of our gardens. I enjoyed the quick tour of your Vassar Farm garden on Saturday – thanks!

    Comment by Ginny — September 11, 2012 @ 1:37 pm | Reply

  4. I’ve never had a pest problem with soybeans, though I had germination problems last year when we got a week of cold, rainy weather while the beans were starting to emerge. Those bean beetles had to be voracious. And the stink bugs are something new to me.They showed up in the garden this year and are disfiguring a lot of my pole beans. That’s a great photo of them. The pest and disease problem certainly has gotten worse with the crazy weather and I, too, am thinking about a lot more row cover next year.

    Comment by Dave's SFG — September 12, 2012 @ 6:25 am | Reply

    • Cold is an expected problem for edamame, thus my June 7 planting date. Rabbits are also expected – but chicken wire around the bottom of the fence keeps them out. The community gardens always have bean beetles but this is the first time in 7 years they have defoliated the soy. The ravening hoards were relentless. The stink bugs are new here also, but not entirely unexpected. Two years ago we ended up with a lot of damaged apples from the local U-pick orchard. The real surprise is there were so few brown marmorated stink bugs last year, considering how many attempted to overwinter in the attic for the last 2 winters. And the things are hearty too; I left a jar of them in a snow bank on my deck for 2 months and they were still alive when they thawed out in March 2011.

      Comment by marysveggiegarden — September 12, 2012 @ 6:39 am | Reply

  5. That is sad news indeed. I battle stink bugs when I lived in TX. they were terrible on everything from sunflowers to tomatoes. I don’t have much issue with them here (yet) Also lucky not to have too much trouble from bean beetles, tho you’d think being only a few hours from Mexico they would be really bad….

    Comment by maryhysong — September 12, 2012 @ 8:50 am | Reply

    • Bean beetles are strange – my two gardens are 2 miles apart – the community gardens have a million of them, but my garden at home has none. My first garden (1978) was 2 miles in the other direction and it too had bean beetles.

      Comment by marysveggiegarden — September 12, 2012 @ 9:08 am | Reply

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