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Farm Feature: Resistant Fruit Varieties
Reduce Risk
 Suppresses
annual weeds with mulches
Improves
soils with animal manure
Uses
disease-resistant varieties
Wisconsin fruit grower Eric Carlson pays twice the price of conventional
fertilizers to feed his half-acre of transitional-organic blueberries
with composted poultry manure, augmented with elemental sulfur,
potassium and magnesium. He calculates that those blueberries need
a half-mile of weeding every two or three weeks — a full mile
if you figure both sides. The semi-load of mulches he buys each
year suppresses his annual weeds, but perennials like sorrel and
quackgrass — the latter so tenacious he’s come to admire
it — persist. At $8 an hour, Carlson’s hand weeding
costs five to 10 times as much as herbicide treatments.
“I know what I’m getting into, so I’m starting
small,” says Carlson. Fortunately, he has an urban customer
base willing to pay what it costs to grow organic lueberries.
Because Carlson sells 95 percent of his fruit right on his Bayfield
County farm — 70 percent of it pick-your-own — he also
has customers eager to sample novel scab-resistant apples like Jonafrees,
Redfrees, Priscillas, Pristines and Liberties. He doubts that would
be case if he were selling his apples wholesale. Fortunately, his
direct-market emphasis allows Carlson to take risks growing diverse
varieties that other producers would be reluctant to try.
Carlson, who earned dual bachelor’s degrees in horticulture
and agronomy from the University of Wisconsin in 1983, first began
following his dreams in 1989. That’s when he left a seven-year
job at the UW fruit pathology laboratory to grow his own hardy blueberries.
Reared in the Milwaukee suburb of Wauwatosa, he chose 40 “exceptionally
beautiful” acres on a finger of northern Wisconsin that juts
into Lake Superior. Gradually, he expanded to 3 acres of blueberries,
1½ acres of raspberries, an acre of fresh-cut and everlasting
flowers and 1,200 apple trees.
Economic sustainability comes first
Environmental sustainability has been an objective of Carlson’s
enterprise from the beginning. “We wanted people to come here,
enjoy the environment and be able to walk around and buy healthy
food,” he says. However, financial reality quickly earned
equal billing.
“You have to make the system economically sustainable first
and then use the tools that are available to you to make it environmentally
sustainable,” says Carlson. “That’s always been
a struggle for me. My ideal is not using any synthetic chemicals,
but I need to stay in business.”
That’s why Carlson now sparingly uses malathion to stop leafhoppers
from infecting his flowers with aster yellows disease, which they
can briskly do within 24 hours. With about a fifth of his 250 flower
species susceptible to the plant-killing virus, Carlson scouts his
fields daily when his climate is ripe for leafhoppers, spraying
once or twice if he must.
It’s also why he has adopted a “low-spray” program
for his apples, treating them conservatively with the relatively
short-lived organophosphate Imidan: twice around petal-fall for
plum curculio and codling moth and about twice after petal-fall
for apple maggot flies. “I feel like it’s the least
amount that I can put out there and still have a marketable crop,”
he says. He times his apple maggot sprays with red visual traps.
Alternative disease management slashes fungicide use
For two years, Carlson cooperated with UW researchers as they built
a predictive model for apple scab around measurements of air temperatures
and leaf surface moisture. Some years, he uses only half as many
fungicides as conventional growers do on his three scab-susceptible
apple varieties — Cortland, Gala and Sweet 16 — while
other years he can eliminate only one or two treatments.
On his 1,000 scab-resistant trees, which outnumber his susceptible
trees five-fold, Carlson applies no fungicides at all. During the
growing season, he quickly cuts out branches showing the earliest
signs of fireblight and, during the dormant season, he aggressively
prunes any possibly overwintering cankers. “Typically, apple
growers spray tank mixtures of fungicides plus insecticides,”
says Carlson. “On my scab-resistant block, I’m not putting
fungicides into the tank, so I feel good about that.”
Carlson planted his apples densely — and consequently more
expensively — on dwarfing rootstocks. That has allowed him
to respond more nimbly to changing consumer tastes, since trees
on dwarf rootstocks typically start bearing in two years rather
than five. While his customers like learning that their apples were
grown without fungicides, Carlson knows that flavor is what sells
fruit and that consumer preferences can rival aroma compounds for
volatility.
Rested raspberries reward their producers
Carlson is also experimenting with alternate-row production in
raspberries. By mowing every other row of his berries, he hopes
to significantly reduce fungicide applications and to use preemergence
herbicides only once every three or four years. “You would
think you would also cut your yields in half, but that’s not
necessarily the case,” he says. “Because of how well
the plant responds to a rest year, the research shows that you can
get up to 75 percent of your normal production.”
According to Carlson, a plethora of cane diseases make raspberries
difficult to raise organically, so he grows them with what he calls
a “basically conventional IPM approach.” He trickle-irrigates
them and makes sure 1½ to 2 feet of circulation-enhancing
space separates his plants, minimizing the odds of raspberry disease.
After almost 15 years as an agricultural entrepreneur, Carlson
likens fruit crops to “waves coming into shore.” They
don’t produce harvests immediately but, like those waves,
they “will come in the long run.” Although working for
himself — and for the health of his customers and the environment
— is less predictable than his old university paycheck, Carlson
makes sure he’s still waiting on the shore by keeping his
risks manageable.
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