Question

An organic farmer is having problems with a particular insect pest in his fields and has consulted the local agricultural extension office for possible solutions. He cannot use pesticides on his fields if he is to maintain his organic certification. You are consulted about the possible use of an entomopathogenic nematode as a means of controlling the insect pest. You need to consider ALL BUT which of the following?

a. Entomopathogenic nematodes are very host-specific, so you must determine if one is available for the particular insect pest the farmer wants to kill.
b. Only certain species of nematodes are entomopathogenic and carry symbiotic bacteria capable of killing insects.
c. You must be wary of the nematode killing beneficial insects like pollinating bees, because they are generalist pathogens.
d. The entomopathogenic nematodes must be acquired when they are in a part of their life cycle during which they can survive outside of the insect host and are infective

Answer 1

(b) Only certain species of nematodes are entomopathogenic and carry symbiotic bacteria capable of killing insects.

Step-by-step explanation:

Only member species of nematode genera; Heterorhabditis and Steinernema are entomopathogenic nematodes (EPNs). They're in symbiotic association with bacteria (Photorhabdus spp and Xenorhadbus spp).

They serve as durable biocontrol agent against invading agricultural insect pest such as armyworm (Spodoptera exempta).

The EPNs penetrate their host and their symbiont release toxins into the insect hemocoel which kills the host over a period of time. The EPNs then feed and reproduce in the cadaver of the insect while the bacteria derive certain nourishment and shelter.