|
Channel Field Check Up
KAYLISSA HALTER
ROBINSON, ILL.
Shortly after planting, growers should start scouting for early-season corn insects that can damage seeds and seedlings. Damage may include seed, shoot or root feeding and may or may not have visible symptoms above ground.
Insect species
Black cutworm (Agrotis ipsilon) larvae grow to about 1 1/2 inches long and its color ranges from gray to nearly black. The skin consists of convex, rounded, coarse granules interspersed between smaller granules. Black cutworm larvae feed below ground and sever corn plants from roots near the soil line. Heavily weeded areas serve as a host for black cutworm moths to deposit eggs. Damage may be more prevalent where corn was planted into thick pre-existing vegetation.
Seedcorn maggots (Delia platura) can be a problem in soils that are high in organic matter because adult flies are attracted to the rich organic material in which to lay eggs. The yellowish white maggot is about 1/4 inch long when mature and feeds on seed contents.
Wireworm (Elateridae spp.) larvae are hard, smooth, slender and wire-like. The larvae range from 1/2 inch when young to 1 1/2 inches long when mature. They range from yellowish white to a shiny coppery color and has three pair of small, thin legs behind the head. Larvae feed on seeds and roots and can bore into the stalk just above the roots killing the growing point. Damage may be more prominent in cornfields that were planted in small grains and sod two to four years prior.
Several species of white grubs can damage or kill corn seedlings by pruning roots and feeding on the mesocotyl. True white grubs, the immature stage of May or June beetles (Phyllophaga spp.), have a three-year life cycle and may cause stand loss during two of their three years. The masked chafer beetle (Cyclocephala spp.) larvae, also called annual white grubs, and Japanese beetle (Popillia japonica Newman) larvae have the potential to damage seedlings but are usually near the end of their larval stage by the time corn is planted.
There are several other insects that may be of concern in your area. Depending on location and field conditions, some other common early-season insects may include chinch bugs, flea beetle, green stinkbug, billbug and grape colaspis. Your Channel Seedsman can assist in identifying which insects may be causing issues in your field and recommend treatments to control them. ∆
KAYLISSA HALTER: Channel Agronomist
|
|