Tag Archives: Agroecology

Valley crops fall victim to water-mold blight

Even in the risky world of farming, a particularly nasty risk is Phytophthora, whose very name sounds scary.

A water-mold blight that can kill entire crops of pumpkins, cucumbers or peppers, Phytophthora capsici is especially problematic because once its spores get into soil, they remain there for years, dormant until the next heavy rains. (Unlike its more common cousin, late blight, capsici’s spores are transmitted by water, not wind.)

“It can take out 100 percent of their crop,” said Katie Campbell-Nelson, UMass Extension vegetable specialist. “There’s a few farmers around here who really specialize in butternut squash, and they’re at particular risk. This is a really big problem for them.”

watermoldBy all accounts, relatively dry conditions this spring and summer kept it from being a particularly bad Phytophthora year around the Pioneer Valley, but farmers such as Mike Wissemann in Sunderland and Peter Melnick in Deerfield reported losses this year.

“We’re running out of places. If you have the right weather conditions, it can rear its ugly head,” even a decade after a field was infected, said Melnick, who said his Bar-Way Farm lost about four of 10 acres planted in butternut squash, after the low-lying field got 4 or 5 inches during one warm September spell. “It’s getting to be a real challenge.”

That challenge is likely to become more intense, with good cropland limited and New England projected to become more susceptible to heavy rain events, with warmer temperatures because of climate change, according to Campbell-Nelson.

But one ray of hope could come from Campbell-Nelson’s test planting of “Caliente” brown mustard as a bio-fumigant cover crop at the UMass Crop Research and Education Farm in South Deerfield.

The brown mustard, chopped up and worked into the soil at the proper time, got the same reaction that Wasabi might draw from someone whose nose was “burned” by the release of the gas it generates, the researcher said with a laugh.

Her test this year of Brassica juncea mustard, measured against control plots of oats on infected soil in the greenhouse, showed it suppressed the disease.

“I got samples of Phytophthora that had been taken from fields around here,” she said. “There are several mating types, so I wanted to make sure we got a good sample of the disease we have in this area.”

Then she inoculated each pot with active “zoospores, which were swimming. If they had a host, they were going to find it. I was creating a disease triangle perfect for the disease: I flooded those peppers, I soaked them, I put the disease in there. I really wanted to see if I could kill those plants.”

The peppers eventually had fewer symptoms of the blight and lived longer, but Campbell-Nelson acknowledged that since it is harder under natural conditions to be certain the mustard is incorporated into the soil during active zoospore, or even semi-active sporangia cycles, it’s probably important to do repeated plantings.

Because the mustard cover — which has no commercial value, especially because it’s chopped into the soil — is from the same Brassica family as kale, it is unlikely to be used by diversified Pioneer Valley growers who want to rotate their fields to other kinds of crops.

And even with repeat cover-crop plantings, mustard is not likely to work wonders by itself, but should be seen as part of what Campbell-Nelson calls a “holistic solution” that also includes reduced tilling, well-drained soils, raised beds and rotating the Phytophthora-susceptible hosts with other crops.

“You should do everything,” she said. “This should be part of integrated management rather than relying on any one method. Never rely on any one method.”

‘No silver bullet’

Wissemann, one of a handful of area farmers who has tried using mustard as a bio-fumigant, reported after losing a pumpkin crop at his Warner Farm to the blight, “There’s no silver bullet, but it helps.”

He added, “We started swapping land with other farmers to prevent monoculture, but part of the risk of that was that Phytophthora ended up being transferred (by equipment moving from field to field.) This is all before we knew what we know now.”

And yet, he added, on a low-lying field that had once been used for growing peppers before it was inundated by the adjacent Connecticut River years ago, “We haven’t had susceptible crops on that field for, gosh, 15 years, and I put some pumpkin out there last year. And sure enough, they had a problem.”

Another recent UMass Extension research project, by plant pathologist Nicholas Brazee, tested for Phytophthora spores in the Connecticut, but found that no samples of that variety, leading to the conclusion that it only spreads the blight if it carries water over already infected soil onto another field.

In some cases, Wissemann and Melnick agreed, the pumpkins had been harvested several days before they showed signs of the disease.

Angela Madeiras, a diagnostician at the UMass Plant Diagnostic Laboratory, said that in addition to flooding of infected fields with poorly draining soil, a leading way Phytophthora spreads is by workers carrying infected soil on their boots, or on farm equipment.

But she added that it is unclear where the problem, which exists in other parts of the world, came from, or how much of Pioneer Valley farmland is affected.

“It’s hard to know how widespread it really is,” Campbell-Nelson said. “It’s like finding a needle in a haystack, because it only presents itself when there’s a flood … condition.”

She added, “Farmers who have had trouble with this disease have gone as far as suggesting they grow cucumbers on trellises, even though that’s on acres and acres, because they’re so at a loss for what to do.”

Even then, added Madeiras, the spores can be splashed up onto the crop by rain. Chemical fumigants exist, but they tend to be expensive and harder and harder to find.

The good news is that practices like using mustard as a cover crop, rotating crops, increasing soil drainage, and reducing tillage can help somewhat, Campbell-Nelson said.


Source URL:http://www.gazettenet.com/home/19439500-95/some-valley-crops-fall-victim-to-water-mold-blight-phytophthora

An Agriculture Revolution – Back to the Basics

By Brent Holiday

A batch of oak and corn bread using some of the acorns that I gathered last fall. They tend to look like a loaf of super dense rye pumpernickel, and have become a significant part of my diet.
A batch of oak and corn bread using some of the acorns that I gathered last fall. They tend to look like a loaf of super dense rye pumpernickel, and have become a significant part of my diet.

My camera is zoomed in on the woodpecker at the top of the tree. As I am about to snap the picture, it hops to another branch. I will never be able to get the bird back into focus unless I zoom out and start all over again. Sometimes it is better simply to start over from scratch. This is where I believe we are at with agriculture. As our target is now increasing New England food production to 50% by 2060 (1), we might benefit from adopting a new form of agriculture to meet our future needs.

One of the major drawbacks of our current system is that it sharply contrasts with nature’s desires, especially here in New England. We have to fight to grow our food, and nature is a persistent opponent. Getting to 50% will be a battle, but it doesn’t have to be accomplished at the expense of the environment. I believe that if we work with nature, we can overcome some of the physical constraints that we face when growing food. The next few paragraphs illustrate how I believe we are fighting against nature as well as make suggestions for a new sustainable agriculture that mimics how nature functions here in New England.

Wood

In New England we have forests but this hasn’t always been the case. In the 1800’s large tracts of forest were cleared to graze animals and raise crops. This seemed to work for a while, but keep in mind that by the early 1800’s we had already decimated the salmon population in Southern New England through a combination of damming, pollution, and overfishing(2). Yet eventually, the farms reverted back to forests as the land was abandoned. Clearing the land was necessary to grow wheat, rye, oats, and corn. They can certainly be grown or raised in some places in New England, however if nature is any indicator, then these crops should not be part of the long term solution.

More appropriate would be using trees as food, since they naturally grow here. Opposed to eating wood? Considering that you already eat wood pulp (3) in your processed foods, this really isn’t such a radical suggestion. However, I think reaping the fruits and nuts that they offer might be more popular. We wiped out our most prolific source of forest carbohydrates, the American chestnut (Castanea dentata), by introducing a fungus about a hundred years ago. Yet the American/Chinese hybrid chestnuts are viable substitutes for the extirpated species. You might even see some of these already at your nearby farmer’s market or Co-op. We also have oaks, which can provide plenty of carbohydrates as well.

Water

It’s pretty wet here, with precipitation year round. All of this water leads to wet soils. In the past we have spent a great deal of effort draining these wet soils so that we could grow grass crops and graze cattle, both of which are generally more adapted to well-drained soils. Turning the beavers into funky hats helped to reduce the amount of wet soils, as the beavers’ dams raised water tables and slowed the amount of time it took precipitation to drain out of the watershed. Some consider them a keystone species, as they drastically alter habitats, which serve to influence the populations of other wildlife species. Perhaps we should take a closer look as what the beaver provides (4). The ponds and marshlands that beavers create are some of the most productive ecosystems that we have on Earth, more productive than both deciduous forests and agricultural land. Farming beavers may entice some more than others (I won’t give away my bias), but we can replicate the systems that they create by forming our own earthworks to catch and store water. We could then take advantage of the productive capacity of marshlands by raising crops such as wild rice (Zizania palustris) and cattails (Typha latifolia). Don’t forget the potential for aquaculture.

forest
Freshwater wetlands vastly out-produce our forests and cultivated lands in terms of primary productivity (vegetative growth), let’s harness this potential with aquatic food crops.

A New Frame of Mind

I have overlooked many other topics for the sake of brevity. My main purpose is to get you thinking. Increasing food production in New England will bring about major changes. Yards won’t be grass, and some of our beloved forests will undoubtedly have to disappear as we take on some of the environmental burdens that we currently externalize onto other areas. It is my hope that with a more regionally-suitable agricultural model we can mitigate some of the inevitable environmental impacts as we increase food production.

To see this become a reality, we need to abandon some of our preconceptions and traditional values. We readily accept change when it comes to other parts of our lives (how many of us still refuse to abandon the VHS, or are wary of trying the internet?), yet agriculture is something we are reluctant to see change.  A new agriculture will bring new foods. Are we willing to eat persimmons and chestnuts instead of bananas and bagels? Only time will tell.

This Northampton, MA resident moose relies on forests and wetlands for local food production. Maybe we should follow suit.
This Northampton, MA resident moose relies on forests and wetlands for local food production. Maybe we should follow suit.
  1.  http://www.foodsolutionsne.org/new-england-food-vision
  2. http://www.fws.gov/r5crc/Fish/za_sasa.html#lifehistory
  3. http://foodtechupdates.blogspot.com/2011/03/cellulose-additives-in-foods-good-or.html
  4. http://www.pbs.org/wnet/nature/leave-it-to-beavers-leave-it-to-beavers/8836/