EPNs 101: An Introduction to Beneficial Nematodes

Nematodes are the most abundant and diverse group of animals on Earth. Some infect plants and animals, but entomopathogenic nematodes (EPNs) only infect insects. This blog series has everything you need to know about using EPNs for biological control of insect pests.

Our resident EPN expert, Sadie McCracken, has big, big plans to research EPNs for biological control vegetable pests while pursuing her master's degree at UNH! We've convinced her to provide us with some basics starting with this introduction.

What  is a  nematode?  

Nematodes are microscopic, worm-like parasites that are found in almost every natural landscape around the world. In agriculture, the two most significant types of nematodes are plant-parasitic nematodes (PPNs) and entomopathogenic nematodes (EPNs). Although PPNs attack plant roots and can be a major crop pest, EPNs – sometimes referred to as beneficial nematodes – only attack insects.

The parasitic relationship between EPNs and insects can be employed by growers to control a variety of crop pests such as: shore flies, fungus gnats, caterpillar larvae, beetle larvae, leaf miners and thrips. Due to their specific parasitic relationship with insects, EPNs are harmless to humans and are safe to use around pets, livestock, and plants.

How do EPNs control crop pests? 

Beneficial nematodes parasitize insects by entering their bodies and infecting them with bacteria from their gut, which causes death of the insect host. Understanding the specific relationships between EPNs and their insect hosts, as well as the life cycle of the targeted crop pest, is key to the successful integration of nematodes into your IPM program.

Nematodes are easy to apply through existing irrigation systems, with a simple handheld sprayer, or even by the placement of infected cadavers into the soil surrounding your plants. Several different species of EPNs are commercially available from suppliers that will deliver them directly to your farm or greenhouse operation.

 

Why should you incorporate EPNs into your IPM program?

EPNs help keep pest populations low enough to prevent significant crop damage, while also reducing the need for pesticides. This is increasingly important for crops grown in protected culture – such as in greenhouses and high tunnels – because there are fewer pesticides labeled for use under these conditions. Decreased pesticide use helps to slow down the development of pesticide resistance, a problem that is happening more often in protected culture. EPNs attack the soil-dwelling life stages of insects that may have otherwise survived a non-lethal exposure to a pesticide, which also lowers the risk of increased pesticide resistance.

With the right combination of IPM, EPNs, and other bio-control methods there is the potential to drastically reduce the need for pesticides in certain crops. Not only can this can save you time and money, but it could expand your crop’s marketability by appealing to consumers that prefer pesticide-free products.

Stay tuned for more useful information from our newest IPM blog series: EPNs 101. In Post #2 we will discuss which types of EPNs are commercially available, what insect pests they control  and how to time your application of EPNs for the most effective control of your target pest.

Additional Resources:

For a more comprehensive introduction to EPNs, what pests they control, and a list of suppliers check out Cornell University’s Guide to Biological Control: Nematodes

Visit the UMass Extension’s page Biological Control: Using Beneficial Nematodes for more information about using EPNs in greenhouse crops.