November 2024 - 10

RESEARCH
Two Cornell studies are examining
how growing in mesotunnels
affect integrated pest
management and pollination.
amount. The open-ended tunnels
received some insects on the tunnel
ends. Because of ease of access, the
on-off-on encountered the most pest
pressure, Murphy said. Bacterial wilt
decreased by 86%.
Acorn squash doesn't like
expect 90% of sunlight to reach
plants. Too much heat can produce
intense rotting, which can increase
powdery and downy mildew more
rapidly, but Murphy said he didn't see
a lot of plant death from it.
The IPM study tested mesotunnels
with fabric, tunnels with a rye and
clover cover crop mix, tunnels with
rye only, and an uncovered plot for
control purposes.
The pollination trial tested three
ways. Mesotunnels covered crops
throughout the season. In openended
tunnel trials, they were
closed except for two short ends
left open for three weeks to allow
natural pollinators to enter from
both sides. In an on-off-on process,
netting was applied throughout the
season except for a three-week
pollination period.
The studies generated a wealth of
data, Murphy said. In the IPM study,
uncovered production experienced
the most insect pressure, while
uncovered acorn squash saw the
highest amount of cucurbit yellow
vine disease (CYVD), at 75%.
Effective bug prevention
" Our most efficacious treatment
for the cucumber beetles and
squash bugs was exclusion, "
10 | NOVEMBER 2024
Murphy said. " Tunnels with weed
fabric had the least insect pressure.
Anything that had a tunnel didn't
show that much disease. We were
able to exclude enough of those
insect pests that we didn't get the
disease pressure that we were
seeing in the uncovered plots. "
The tunnel with the rye and
clover cover crop mix and rye by
itself experienced some weed
pressure that accompanies cover
cropping. The fabric helped keep
weeds from the muskmelon, but not
100%. Landscape fabric provided
equivalent suppression to cover
crops. In acorn squash, landscape
fabric was more effective for weed
suppression, due to less cover
crop biomass.
The most marketable fruit came
from the tunnel and the fabric
treatments, at 70%, with cover
crops and uncovered producing less
marketable fruit, likely due to light
competition with the cover crops.
The uncovered plots produced more
soft fruit that was more prone to
rotting or fungal imperfections,
Murphy said. In both studies, netting
produced no significant change on
fruit yield, Murphy said.
In the pollination results, the
full season mesotunnels excluded
cucumber beetles by a significant
growing in mesotunnels. Because
researchers planted a variety that
grows large, leaves pushed up on the
netting, allowing insects to feed on
them through the netting. Shorter
varieties, less than 3.5 inches in
height, would work better in tunnels,
Murphy said.
" It all depends on the increasing
importance of CYVD, " he said. " We
now have a population in New York,
thanks to our squash bugs. It could
be coming to Pennsylvania. "
Entomologists at the University of
Kentucky found that bumblebees are
unsatisfactory cucurbit pollinators.
Squash bees and syrphid flies are
more effective cucurbit pollinators,
Murphy said.
Netting effectively excluded most
insect pests the researchers wanted
to bar, Murphy said. Muskmelons
saw zero CYVD or bacterial wilt.
Cover crops were effective for weed
suppression. While weed fabric was
obviously the best, that method is
more labor intensive, he said.
Overall, Murphy said the
mesotunnel system could be costeffective
for short cucurbit cultivars
as well as higher-value crops.
Material costs, which have increased
recently for netting and weed cloth,
are factors to consider.
While the study's three-year grant
ended, on-farm trial data collection
is ongoing. An economic analysis
is also being conducted and will be
posted at cucurbit.plantpath.iastate.
edu.
November 2024

Table of Contents for the Digital Edition of November 2024
