Slugs and millipedes like the rain
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EmailEditor’s note: This article is from the archives of the MSU Crop Advisory Team
Alerts. Check the label of any pesticide referenced to ensure your use is
included.
With
the recent rains, slugs are common in some fields. Slugs feed on
cotyledons, stems and leaves of emerging plants by scraping the leaf
surface. With heavy damage, leaves take on a tattered appearance. Wet
conditions favor slug populations, thus no-and reduced till fields with
residue are at greater risk for slug feeding, especially if plants are
emerging and growing slowly. Slugs are hidden during the day, but
silvery slime trails may visible. To check for slugs, move residue aside
during the day or walk fields at night. Another trick is to put
something flat (like old shingles) out in the field overnight, by
daybreak, slugs often accumulate on the underside. Seed treatments do
not control slugs. Baits containing metaldehyde are very effective, but
expensive. Drying conditions and good crop growth are the best solution
to a slug problem.
Phil Kaatz from Lapeer County visited a wireworm-damaged field this week, only to find millipedes as the true culprit (view photo).
This is a rare, but increasing find, in parts of Ontario, Indiana and
Michigan. A few years ago, several wet fields near the Tittabawassee
River in Saginaw County lost stand due to millipede feeding. In all
cases, the affected fields are wet and have a lot of crop residue.
Millipedes are normally beneficial, feeding on decaying plant material,
but under unusual conditions they can damage seeds and emerging plants.
Millipedes are distinguished from other long, brown insects (such as
wireworms) by being “leggy,” with four legs on each body segment.
“Milli” means a thousand in Latin, and “ped” means foot, thus literally
“a thousand-feet.” Millipedes are not insects, and seed treatments do
not seem to impact them. As with slugs, drying conditions and good crop
growth are the solution to overcoming a millipede infestation.
