Tree Fruit IPM Entomopathogenic Nematodes
What are Entomopathogenic Nematodes?
Overview
Nematodes are microscopic worms that lack color, body segments, and appendages. Beneficial nematodes often work by attacking and killing a host through entering their body, releasing bacteria, and then eating the host's tissue. Nematodes in the genus Steinernema act as biological control against pests, usually larvae, in the soil. Because nematodes are highly effective at killing many pests, safe around humans and animals, have been shown to not kill beneficial or non-target pests, and organic, using them as pest control is a safe and viable option for many crop growers.
ID/Life Cycle (Figure 1):
Infective juveniles (IJs) locate a host and enter through an opening or the membrane in between segments of the host's body. Once inside they produce symbiotic bacteria that cause the host to die, allowing the nematode to feed on the bacteria and liquified host tissues. The nematodes feed and develop into male and female. In the genus Steinernema, reproduction occurs through cross fertilization between males and females. If enough food is available, 2-3 generations will be produced within the host, which will then emerge from the cadaver as IJs and find new hosts. The life cycle (Fig. 1) usually lasts a few days under optimal conditions.
Field Application:
One way to use EPNs in commercial apple orchards is to apply them at the base of apple trees to kill the soil-dwelling stages of plum curculio. This is done by applying a certain amount of nematodes (e.g., 1 million IJ/m2 ), along with some water (depending on how saturated the soil is) into the soil. This should be done after apple fruitlets, suspected to be infected with plum curculio larvae, have fallen. The EPNs will attack and kill the plum curculio larvae, leading to a decrease in adult emergence.
For a video showing EPN application against plum curculio under field conditions click HERE
Date: December 2021
Author(s): Jaelyn Kassoy, Dorna Saadat, Prabina Regmi, Elizabeth Garofalo, Dr. Jaime Piñero
Visit our website: http://ag.umass.edu/fruit
Additional information available on the MYIPM app: https://apps.bugwood.org/apps/myipmseries/
Note: This information is for educational purposes only and is reviewed regularly for accuracy. References to commercial products or trade names are for the reader’s information. No endorsement is implied, nor is discrimination intended against similar products. For pesticide products please consult product labels for rates, application instructions and safety precautions. The label is the law. Users of these products assume all associated risks.
This work was supported in part by funding provided by USDA NIFA Extension Implementation Program, Award No. 2021-70006-35388.
