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Flying V Farmers  |  Flying V Farm  |  Placerville, CA

Subject: Seeking Garden Symphylan Guidance

Hi all,

My name is Grayson, myself and three others started a diversified fruit and veggie farm in Placerville CA this January.

We are learning that we have a Garden Symphylan (GS) infestation in parts of our veggie field. I have found them on the roots of crop plants, as well as lured them with potato slices. They have seriously damaged patches of direct sown spinach, killing or stunting plants just after germination, seems to be stunting growth on transplanted parsley and currently are attacking our direct seeded squash as it germs, killing some before they break the soil surface. It is presenting in patches, and is especially hindering direct sown crops. I have found them in numbers up to five per plant in the bad spots, and 15+ on some of the potato lures. It's definitely impacting our yields and causing us to worry about the suitability of the site.

After reading though some literature on GS it seems there isn't really much clarity on good management practices, and no feasible way to totally eradicate them. We definitely don't expect a single definitive answer but hearing of experiences, resources and techniques other growers have used to monitor and manage GS would be awesome. If you know of resources or experts to contact thats definitely of interest too. Practical ideas, experience, and hunches, from the scientific to the kooky welcome.

Specifically we're trying to figure out:
- Is this a lost cause for some crops or parts of the field?
- Are there things we are doing that might have contributed to high GS this spring?
- What should we consider to reduce populations or strengthen plants to withstand the GS (timing, tillage, soil fertility, transplant size etc.)?
- Are there crops people have had success growing with GS infested areas, are there crops to definitely avoid (our experience has matched the literature in some ways and not others e.g. major GS damage on spinach, but we're growing mustard greens without problem)?
- Are there things we need to consider to keep the infestation from spreading (cleaning equipment, managing infested patches, managing fallow spaces, etc.)?
- How do we best monitor populations, map infested spots, assess damage, and assign action thresholds (GS seems wily and hard to predict)?

We are considering trying:
-mapping infested spots as we find them
-tilling more aggressively / stale bedding and re-tilling
-rotating potatoes, winter cover of oats, or other crop / cover to reduce populations
-planting more and bigger transplants and less direct sown
-solarizing with silage tarps before planting
-applying shrimp and crab meal

Site and practices

The field we are using is bottom land in a small Sierra Foothill valley at 2400'. It is pretty flat and has a rich, loose, alluvial soil, 2.5 OM 6.5 PH with pretty good structure in the top 3 feet, underneath which is a thick clay layer. Topography and soil make it quite wet and cool into the spring. Land use history is as a pear orchard then a pumpkin patch until ~2000, then fallowed as a meadow of grasses, feral cover crops, and blackberries for the last ~20 years. We ripped the meadow grass in early spring then disced and tilled before planting.

Our current tillage and soil prep practices are primary tillage with a chisel plow, and disc, followed by roto-tilling. In general we have kept tillage to as few passes a possible. We are currently not set up to raise beds, but want to do so. Fertility by broadcasting as per soil analysis. We also gave the field a heavy dose of compost this year and want to continue with smaller applications in future years.

Respond here or email me at: grayson@flyingvfarmca.com

Thanks!

~Grayson

In Topics Soil Fertility Management, Seed & Planting, Pest & Disease Management, Beginning Farmers & Ranchers

In General FarmsReach community

Comments 19
06/02/18, updated
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  |  NCAT/ATTRA  |  Davis commented

So, I recall attending a Soil Food Web seminar back in 2002 in Santa Cruz, with Elaine Ingham, and we went to UCSC farm/garden, which has major symphylan infestation at the time, and Elaine claimed that the soil was "out of balance", and that symphylans only are primarily fungi feeders, which didn't match my, or Jim Leap's observations. I think symphs are opportunistic, feeding on fine plant roots and/or soil fungal mycelia, as the opportunities arise. Both Jim's and Mike M's experience underline the idea that incorporated cover crops provide large boost to population numbers, likely through symphs feeding on fungi, as well as the ease of transport in the upper layers of the soil, with so many transport routes (roots?) in the top soil layer from decaying cover crop residue. Because they migrate vertically in the soil profile, their population numbers can be pretty random, as Jim L mentioned. it's

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08/19/18 4:29 PM
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  |  P.J. Dunn Working Redworms  |  Galt, CA commented

Hey Grayson!

I see in your post and comments re: pests a reference or two to crab shells. I'm doing a small test area of my worm ricks w/ a crab meal application every feed cycle together with a large scale tea brewing operation. This is really an extension of the work that George Hahn has been doing with chiton and effectiveness as a insect repellent for 30 years! Don't know if you remember our 'smallest mechanized commercial worm farm in the world' status or not. It does give me the ability to work with small scale experiments like this. ~~~ Michael

08/18/18 6:33 AM
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  |  exterminator north jersey  |  Burlington commented

A nice info!!

08/17/18 11:36 PM
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  |  Floodgate Farm  |  Redwood Valley, CA commented

I was told tilling and keeping organic matter low would help. Fortunately I ignored that advice. My OM went from 5% when I had a limited infestation 3 years ago to 8 or 9% now. They seemed to have come in on some goat manure. I do little soil disturbance, just to get plants in. Symphylans now do negligible damage so the fact they eat fungal hyphae which are probably more abundant now seems the case here. I'd suggest no till and transplanting into cut-down areas (cut don't dig in cover crops) or if planting into the just-harvested crop, cut those plantsyou are done with just below surface)

07/16/18 10:29 PM
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  |  best exterminator nyc  |  Rochester commented

Pests are the serious issues every human is facing in their daily lives. many of the gardeners and farmers have lost their crops due to such creepy pests like springtime, and rats, mice, etc. Just a few days ago one my aunt was complaining about the rats shearing to the corn crops in her farm, so one of her friends suggested her to contact best exterminator NYC as she was living in NYC.

07/14/18 2:43 AM
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  |  School Road Farm  |  San Juan Bautista, CA commented

Hello Grayson,

Sampling protocol

We found, in all of our symphylan work at the UCSC farm, that the most accurate sampling method was to sample each year following incorporation of cover crop just prior to bedding. We would lay out a 10' X 10' grid pattern on our entire production area and very carefully set out potato pieces on that pattern. Jon Umble did all of this work and spent a considerable amount of time at it. It takes patience and diligence and consistency to get good data. He utilized Arc View GIS mapping software to assist in analysis. He used colors to represent symphylan populations. He made these beautiful maps of our entire 25 acre production area that were very easily interpreted. We did this type of sampling in subsequent years on smaller production areas to identify potential trial areas. This is definitely the best approach - it is very time consuming but well worth the

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06/04/18 8:21 AM
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  |  Flying V Farm  |  Placerville, CA commented

Some additional thoughts / questions

Sampling and evaluating methods: Considering the unpredictability and randomness of distribution are there suggestions on how to evaluate different methods? It seems like part of the reason everyone has a different idea is it's really hard to know whether something is working or not. The bad spots are supposed to be persistent over time so I was thinking of mapping out a few and comparing methods between spots or on sections of an infested spot but this seems like a pain and would require the same crop timing, etc. I could sample on a field/bed/block basis with the potato method but its always going to depend on where I put the potato and when I look at it to count... And just continuing to plant into it and try different things different years seems like a great way to waste time and money without yielding comparable results.

Rotation: Are there crops other

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06/03/18 11:10 PM, updated
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  |  School Road Farm  |  San Juan Bautista, CA commented

Based on my years of experience in dealing with and studying symphylans I can definitely say that there is a lot of anecdotal advice floating around out there. I think the ATTRA publication is the most straightforward write-up available. Symphylans feed on roots but they also feed on fungal hyphae that is present during fungal decomposition of cover crop residue. This explains why their populations can get so high following cover crop incorporation and it also explains why cool wet springs are often more problematic. I think it also explains why Mike Madison noticed less symphylan pressure in ground that was winter fallow.

The trick with doing any type of trial work with symphylans is that their population patterns are extremely random thus making any type of traditional experimental design (e.g. randomized complete block) completely worthless when attempting to identify effective control measures or

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06/03/18 1:13 PM
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  |  Rincon-Vitova Insectaries  |  Ventura, CA commented

Elaine Ingham sez that symphylans eat fungus so work toward a fungal dominated soil food web. If the symphs don't have fungus to eat, they eat your crop roots. Tilling reduces fungus, so moving toward no-till beds would seem to help. From carbon sequestration standpoint, growing perennial vegetables would help reduce your carbon foot print. Tilled, row crop veggies was a route for newby organic farmers to enter the market with minimal infrastructure. Maybe it is time to move on to regenerative organic farming/horticulture. I'm working on a food forest myself.

06/03/18 12:40 PM
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  |  Flying V Farm  |  Placerville, CA commented

Thanks everyone, a lot to chew over here.

Rachel, The tarping idea was suggested by another foothill farm that has had persistent problems. They solarized for weed control, but ended up finding it also reduced symphylan populations (I think it was early carrots and beets). Crustacean meal has some anecdotal support, supposedly boosting populations of microbes that attack insect eggshells and exoskeletons, however the same farm who tried the tarping used shrimp and crab meal and didn't notice any effect. Both seemed like they could help but generally it seems really hard to identify whether or not these strategies are actually working, since they move up and down the soil profile seasonally, and populations seem to vary dramatically based on weather.

I'll email you so we're in touch and would love to share resources if either of us come across anything.

~Grayson

06/03/18 11:31 AM
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  |  Our Table Cooperative  |  Sherwood, OR commented

I struggled with symphylans in Oregon, and the only thing that definitely worked was growing potatoes, which would give us one good crop after the potato crop before the symphylans started coming back quite quickly. Transplanting helped, but they would need to go in excellent condition and be kept in excellent condition free of pests and other stresses. And tomatoes planted out of 4-6" pots would still be set back significantly.

The tarping sounds like a good idea, though it would probably need to be for a long period to wipe out all plants and residue, and in the short term populations might increase due to to the darkness. Tilling maybe helped a little in the short term for direct seeding/transplanting, but only if you were planting immediately after and not waiting a day or more, or if a crop was failing tilling it in and immediately replanting seemed to have a 50/50 success rate. Otherwise, could

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06/03/18 11:00 AM
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  |  Yolo Press  |  Winters, CA commented

We're also having an exceptionally rough GS year here in the Sacramento Valley, west side (Winters). Many crop failures, both transplants and direct seeded. Presumably this is weather-related. Ordinarily, this is seasonal (spring) and by July the problem will have gone away. I'm not sure if that's true at higher altitude.

When I'm planting over-wintering cover crops in the fall (cereals/vetch/peas/beans) I usually leave some ground bare (3/4 acre or so) to have it available for early spring planting in case we have a wet year. If we get a dry spell in Dec-Jan I might disc it just to keep it bare. What I noticed this year is that ground that was bare over winter has no GS and plantings there do fine; ground where I had a good stand of cover crop has the worst GS problems. So you might want to leave some ground unplanted to cover crop and worked up in the fall for spring planting as a means of

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06/03/18 9:56 AM
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  |  Lunita Farm  |  Napa, CA commented

Hi everyone,

I'm following this conversation. I'm actually facing the same challenge, and intended to start a similar thread this weekend. I began a mixed vegetable farming operation on 3/4 acre of land in Napa this past December/January on a former horse pasture (starting with an overwintering cover crop of vetch, bell beans, peas, barley, rye, and daikon radish), and I am also finding symphylans damaging many of my crops. I've been researching and reading up on it, and I'm not finding a whole lot of information and solutions are out there.

Jim Leap, its very encouraging to read your post and that you were successful in reducing symphylans over time. What cover crops did you use most that seemed to help eliminate symphylans?

I am also finding conflicting information about the use of tillage. Some sources are saying tillage reduces symphylan population, while others say tillage reduces natural

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06/03/18 9:43 AM
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  |  School Road Farm  |  San Juan Bautista, CA commented

Hello Grayson,

Seems like you have already done a lot of research into your symphylan issue. Based on your proposed strategies for dealing with symphylans I am guessing you have read the ATTRA Symphylan publication.

If you haven't here is a link: https://attra.ncat.org/attra-pub/viewhtml.php?id=127

Seems like you are on the right track. From your description of land history it would make sense to me that you would have some symphylan pressure - especially given our late wet and rather cool spring. Bringing ground into production that has been fallow with a perennial grass is problematic. I managed the UCSC farm from 1990 through 2010. When I first got there I initiated a perennial rye rotation as a component of our mixed vegetable production system with the hope of improving soil quality over time. Initially I left the rye blocks in for three years. When we started noticing symphylan damage we

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06/03/18 7:27 AM
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  |  Community F.A.R.E.  |  Frederick, MD commented

Go to http://dirtdoctor.com and see if Howard Garrett can help. He knows a lot about beneficial insects
06/03/18 6:15 AM
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  |  UCCE  |  Woodland, CA commented

Always check the pesticide label to determine which crops Aza-direct is registered on.

06/03/18 5:37 AM
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  |  UCCE  |  Woodland, CA commented

Here's a good resource on garden symphylans, http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=18819: Insecticides Effective Against Garden Symphylan

Aza-direct is the only organically approved insecticide that elicited repellency.

06/03/18 5:34 AM
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  |  Classic Organic Farm  |  Gaviota, CA commented

GS are less active in the winter. In Southern California we only planted vegetables in the infected field during the winter. In the summer we planted cover crops such Sudan grass.

06/02/18 11:54 PM
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  |  Flying V Farm  |  Placerville, CA commented

Forgot to note:

We are certified Organic and also want to do right by the land. So any ideas would need to be Organic approved, and hopefully geared to minimize negative/destructive impacts.

06/02/18 9:33 PM, updated

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