Garden symphylans

Another flurry of activity came and went on Saturday.  A group of Boy Scouts and their parents stayed for about four hours in the morning, and a few individual volunteers helped us finish out the day.  When I look back on where we were at the beginning of the week, what we're able to do accomplish with our diverse, unpredictable labor force is truly astounding: pot up all the plant sale tomatoes, plant out fifteen full beds of transplants and direct seeded crops in the fields, harvest a trailer full of chard and spinach for the food bank, seed over 70 flats of new crops, and more and more and more.  And there's the less tangible gains, too: young men learning to work hard together in a humid greenhouse, interns learning endless minute details about the farm on their first field walk this month, journalism students crafting our story into a seamless article for their classes, and twenty teenagers-- some more nerve-wracked than others-- giving their first job interviews.  Our visible achievements always get the glory and recognition, but for me the invisible is just as important.  And for all the conversations about life, learning about plants, skill-building and muscle memory developing in everyone's bodies and minds, I leave the week with persnickety obsession with what we have yet to accomplish.  It's such a relief to look backwards, see what we've done, hear feedback from people about how they've grown.  Maybe even more than the plants have.

Sometimes, that growth is wildly uneven.  We grow and learn only because the plants don't thrive as expected.  Take the first round of spinach from the greenhouse.  We planted it alongside our cold-stressed cucumbers for a quick side harvest before the cucumbers took over.  The cucumbers don't seem to be taking over anything at this point, but much of the spinach thrived.  I harvested some for restaurant orders earlier in the week, sent home bags and bags with volunteers, and threw some into my lunches every day.  Like every greenhouse spinach harvest on the Youth Farm, it was the most tasty, tender, gorgeous spinach I'd ever had.  The mounds of huge rounded leaves enveloped the cucumbers in many parts of the beds.  But some just sat there, tiny and yellowing, starting to wither and wilt right next to its voluptuous neighbors.

I mentioned briefly in my evening photo journal that I thought garden symphylans were responsible for this stunting.  It was the classic symptoms of an infestation: plants that just sit there, put on no new growth, and slowly start to give up on life.  On Saturday, the Boy Scouts and a couple UO Urban Farm students helped harvest the spinach and pull out the plants to make room for the cucumbers, and we took the opportunity to investigate the soil.  

 Garden symphylans: tiny white centipede-looking arthropods that feed on fine root hairs

Garden symphylans: tiny white centipede-looking arthropods that feed on fine root hairs

Indeed, the root balls of the stunted spinach plants were getting moldy and were infested with tiny white arthropods scurrying among the roots.  Why some plants were able to withstand and grow past these pests, I can't say.  The ones that succumbed were clearly being eaten to death from the root hairs, and it was a relief to put them out of their misery.  The Pacific Northwest Pest Management Handbook does not give very encouraging information for anyone struggling with symphylans.  Once plants start to exhibit damage, it explains that "little can be done without replanting."  The prognosis sounds dire: "No simple, inexpensive, and completely reliable method of controlling GS has been developed. No method will eradicate GS from a site, and the effect of most tactics will not last longer than one to three years. Very little is known about symphylan population dynamics in agroecosystems due to the complexity of their movements up and down in the soil profile. Many control tactics have been successful in some cases but unsuccessful in very similar situations."  Basically, plants are screwed once symphylans start to feed on their roots.

So what to do in our greenhouse where these little beasts have proliferated?  Tillage is apparently one of the best cultural controls, since it smashes the pests and breaks up their prime habitat: structured, organic matter-rich soils.  Their populations tend to remain low for a few weeks after tillage, which is enough time for new crops to establish good root systems.  Planting another susceptible crop in that same area though, even after tillage, would be foolish.  Similar to the tactic in the Field One, where they demolished our onion crop last year, we may end up growing potatoes in these greenhouse beds.  According to the PNW handbook, "Populations have been shown to decrease significantly in potato crops, even allowing subsequent cultivation in rotation of susceptible crops. Though at this point no other crops have shown to be nearly as effective as potato, numbers have also been found to be lower after a spring oat (‘Monida’) winter cover crop than after a mustard (‘Martiginia’), barley (‘Micah’), or rye (‘Wheeler’) winter cover crop. Mustard and spinach crops have been shown to be very good hosts, and may lead to increasing populations in some cases."  As always, we'll just do our best under the constraints we have (space, harvest needs, timing, weather, people powers, etc).

I guess this is how our intangible efforts eventually become tangible.  We're observing as much as we can, showing each other what we see, asking more questions, and eventually coming to conclusions and practices that we can implement to become better growers.  This week's victory?  The visible growth of potatoes from a field that just last year was speckled with stunted onions and leeks from a symphylan infestation.  You lose some, but you win some, too.