The sun is out, fields are drying and temperatures are increasing, but as pest managers inspect crops that have been subjected to an extended period of poor growing conditions, a multitude of critters are being found in the soil, said Purdue University experts.

Some are known pests and several are being falsely accused of causing stand reductions, said John Obermeyer and Larry Bledsoe, both Purdue Extension entomologists.

Obermeyer and Bledsoe ruled out wireworms and nematodes placing the blame elsewhere.

They explained that millipedes are wireworm-like arthropods, having two pair of legs per body segment that move quickly above and below the ground. They have become more prevalent since the advent of no-till. When found, their numbers are often high. Millipedes typically feed as scavengers, feeding on dead or decaying materials often associated with seeding blights.

They have rarely been documented as pests of corn, but several pest managers have reported numerous millipedes in and around corn kernels/sprouts that have been in the ground for two or more weeks. The opportunistic millipedes were hollowing out these “blank” kernels that were in the early stages of decay.

Obermeyer and Bledsoe said it’s not nematodes. Baby earthworms and potworms are closely related and common animals found in soils. They are small, colorless and often less than a quarter of an inch long. These worms feed on damaged decaying plant remains, not living tissue. Therefore, they are closely associated with the decaying plant parts and surrounding soil and often wrongly accused of damaging seedlings, they said.

The two entomologists recommend that pest managers should keep an open mind when diagnosing field problems.

Many other critters such as mites, symphylans and springtails, are being observed on or around rotting seeds/seedlings. They are small, some fast moving and unfamiliar to most. They are not causing the poor emergence or growth, but taking advantage of weak and dying plants in various stages of decay.

The real blame of early season damage should be attributed to grubs, wireworms, seedcorn maggots and cutworms, which are all being reported throughout the state with varying degrees of damage, they explained. This doesn’t come as a surprise, considering once again the growing conditions this spring.

One message that has been repeated is that the low rates of seed-applied insecticides are not preventing economic stand losses from grubs, wireworms and cutworms. The product label specifies “protection,” from these early season pests. The problem is that these systemic insecticides require a vigorously growing plant for uptake, yet they are most needed when the environment is not conducive to growth.

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