Crop Insurance Today Third Quarter 2020 - 13

These infested soybean plants are wilting and mostly dead. Damage such as this can extend well into the field and result in 100 percent yield loss in
affected areas.

He split the stem and proceeded to pick out tiny
white and orange insect larvae. Justin said they
had caught an adult earlier in the season and it
was a new pest that was yet to be identified. In
that area, there were numerous plants displaying the same symptoms, so I pulled one up and,
sure enough, larvae were found burrowing in
the stem. The adult midge that was captured was
a new midge species that now has a scientific
name, Resseliella maxima, but is commonly referred to as Soybean Gall Midge. And it has some
well-known relatives, including the Hessian fly.
Justin began working with NCIS on the corn
research and, last August, I returned to Nebraska
to visit some new corn stand reduction research
on the Mead farm. While driving in Eastern Nebraska on our way to see the popcorn stand reduction research near Central City, we saw many
fields where the new insect species was damaging
plants. It was obvious. Justin was concerned be-

cause damage was extending further into fields
in 2019. And, in some cases, most plants in the
infected areas were dead.
It is possible that the Soybean Gall Midge
has been in Nebraska for nearly a decade, but no
one knows for sure. In 2011, orange larvae were
found in plants that were, for the most part, hail
damaged or diseased. They were ignored because
the insect damage was not prevalent, and the
emergence of the adults occurred later in the season. At that time, larvae were not collected so researchers are not certain if those larvae were Soybean Gall Midge. But, in 2018, growers in more
than 60 counties started to notice a midge and,
with damage detected early in the season, entomologists and soybean agronomists took notice.
It is not every day that a new insect threat that
attacks one of the nation's most widely grown
crops is discovered in the central United States.
As a new species, little is known about the Soy-

bean Gall Midge. So, last year Justin and colleagues from Iowa, Minnesota, and South Dakota set traps to capture adults to learn about their
emergence patterns. While sampling was limited, they discovered that three generations can
emerge in a single season. One generation that
overwinters in previous year's soybean fields, and
two generations that come from larvae produced
in the current season.
When adults emerge, they look for a place to
oviposit eggs. Early season emergence in June
coincides with when soybean is typically in the
early V-stages. At these growth stages, soybean
stems are rapidly enlarging and often develop
stem fissures-cracks along the stem length.
Adults tend to lay eggs near the soil line on the
developing soybean stems and fissures are believed to be a possible location for ovipositing
eggs. This provides easy access into the pith of the
soybean stem when the larvae hatch.
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Crop Insurance Today Third Quarter 2020

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