Invasive Species

This page includes information on common invasive species in the area.



Invasive Plants

Invasive plant species are a common problem across the United states. In Ohio, we have many resources to help combat these plants while promoting a healthy diverse ecosystem.

Palmer Amaranth

Palmer Amaranth (source: OSU extension)

Palmer Amaranth (Amaranthus palmeri) is an aggressive, invasive weed native to the southwest region of the United States and northern Mexico. It has become a significant pest problem in the southern US soybean and cotton region. This plant is resistant to many herbicides including glyphosate, which makes it a difficult pest to control once it becomes established.

The plant is highly adaptable and is able to produce 100,000 seeds per plant. Its high growth rate and height (6 feet +) can cause significant yield losses and harvesting issues. If the plant is allowed to seed out, control will be difficult. Early detection and removal before seed heads form is best to combat this plant.

In Ohio, it has been found on multiple sites, with most eradicated before seed formation, however, there are a few sites that have more severe infestations. The introduction of this plant can come from contaminated farm equipment, livestock feed, or from contaminated seed sources outside Ohio where Palmer Amaranth is present. It can come in from any seed source, including wildlife food plot mixes and deer feeder food. It is recommended to have your seeds tested by the Ohio Department of Agriculture to ensure noxious weeds are not present before planting them on the properties that you manage.

If Palmer Amaranth is suspected on your property (there are native look-a-likes), contact any agricultural related office to report and get experts on site to confirm. There are many websites devoted to its identification and control; become familiar with this plant, as it is likely headed our way.

Marestail (Horseweed)

Marestail (source: Boggs, OSU)

Marestail, also known as horseweed, is widespread in the Midwestern United States. Marestail is an annual plant that has high tolerance of drought conditions. The rapid growth of this weed can lead to germination of seeds in early spring, proving to have little resistance. If left untreated, marestail can severely inhibit the production of soybeans. However, almost all populations are resistant to glyphosate and ALS inhibitors. Check these articles from OSU Extension regarding the control of marestail.

Invasive Pests


Crop producers constantly deal with the potential of pests interrupting the growth of their produce. The following pests are identified as potential threats to co0rn, soybeans, and wheat in Southwest Ohio.

Corn Pests

Black Cutworm

Black Cutworm (source: Ohio Country Journal)

Black Cutworm (source: OSU)

The Black Cutworm (BCW) is a species of pest that attacks emerging corn plants. . BCW eggs are laid on the leaves of weeds in untilled crop fields. In their larval stage, they burrow into the base of the corn stem, leading to the plant’s collapse. BCW larvae are about ½-2 inches long with gray/black coloration. They burrow into the soil during the day and emerge onto the soil surface at night. The threshold for BCW in Corn fields is 3% of all plants. Some management strategies include early tillage and Fall weed control. For more information, see Ohio State University Extension Bulletin 545, Control of Insect Pests of Field Crops, for those insecticides labeled for black cutworm, or for all insecticides labeled on corn.

Corn Rootworm

Western Corn Rootworm (source: University of Idaho)

The Western Corn Rootworm (WCR) is a leaf beetle that feeds primarily on corn roots and leaves. The WCR is known for attacking corn following soybeans. The rootworm larvae bore through major root systems and nodes, while the adult moths eat through the leaves. These can be managed with seed treatments or soil pesticides. The threshold for emergency treatment is five adults per plant prior to pollination. For more information, see Ohio State University Extension Bulletin 545, Control of Insect Pests of Field Crops, for those insecticides labeled for corn rootworms, or for all insecticides labeled on corn.

European Corn Borer

European Corn Borer (source: University of Maine Cooperative Extension)

The European Corn Borer (ECB) is a pest that infests corn plants across the state. The ECB bores into the stalk of the corn plant disrupting the nutrient uptake of the corn plant, this making it more susceptible to diseases and stalk degrading. Management of ECB includes transgenic hybrids such as Agrisure, Herculex, and YieldGard, each of which carries a Bt-corn borer gene. Foliar treatment may also be an option. For more information, see Ohio State University Extension Bulletin 545, Control of Insect Pests of Field Crops, for those insecticides labeled for European corn borer, or for all insecticides labeled on corn.

Soybean Pests

Bean Leaf Beetle

Bean Leaf Beetle (source: OSU Extension)

The Bean Leaf Beetle (BLB) is a pest that attacks young soybean sprouts. It is either green or gold with four black spots on its wing covers. Treatment is justified if the percent pod injury is reaching 10–15%, and BLB adults are still present and still active. For more information, see Ohio State University Extension Bulletin 545, Control of Insect Pests of Field Crops, for those insecticides labeled for bean leaf beetle, or for all insecticides labeled on soybean. 

Cyst Nematode

Soybean cyst nematode (SCN), Heterodera glycines, was first identified in Ohio in 1981 and has now been found on soybean in 72 of the 88 Ohio counties. SCN damages soybeans by feeding on roots, robbing the plants of nutrients, and providing wound sites for root rotting fungi to enter. The severity of symptoms and yield losses are

Cyst nematode (OSU Extension)

Cyst nematode (OSU Extension)

dependent on several factors including: the number of nematodes present in the field at planting, the soybean variety, tillage practices, soil texture, fertility, pH, and environmental conditions during the growing season. Once SCN is established in a field, it rarely is eradicated. SCN is the leading cause of soybean yield loss in North America and now occurs in all major soybean production areas worldwide.

Symptoms and Signs

Symptoms are highly variable. Symptom development depends on several factors, especially population densities of the nematode, the presence of other pathogens, soil nutrient status, resistant soybean varieties planted previously, and rainfall. Often, yield is reduced when there are no visible symptoms. SCN injury can also easily be confused with other crop production problems such as nutrient deficiencies, injury from herbicides, soil compaction, or other diseases. Moderate symptoms include circular to oval patches of yellowed plants with reduced yield (Figure 1). Affected areas may increase in size each year, usually in the direction of tillage. Severe symptoms include patches of very stunted plants and lower yields.

Soybean Aphid

Soybean aphid (source: OSU Extension)

Soybean aphid (source: OSU Extension)

Soybean aphids are pests that disturb the growth of soybeans. Soybean aphids secrete honeydew onto the surfaces of the soybeans, causing the leaves and beans to develop mold. The threshold of Soybean aphids is most likely surpassed if adults are present on leaves. Therefore, Treatment for soybean aphids is only suggested if the soybeans are most likely salvageable. For more information on soybean aphid management, see Ohio State University Extension Bulletin 545, Control of Insect Pests of Field Crops, for those insecticides labeled for soybean aphid, or for all insecticides labeled on soybean.