What are Biocontrol Nematodes?

• Biocontrol nematodes are also known as entomopathogenic nematodes or “insect attacking” nematodes.  These nematodes are naturally occurring in most soils around the world used for agriculture.  

• However, the naturally occurring species are in very low numbers and are usually not adapted to attack the soil insects attacking most agricultural crops.

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Do Biocontrol Nematodes feed on crop roots?

• Biocontrol Nematodes predators of insects and do not feed on plant roots.  

• The Infective Juvenile stage in the soil is non-feeding and survives on its fat reserves while searching for soil insects to attack, kill and reproduce in.

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What about the nematodes that attack my crops?

• The nematodes that attack crop roots are Plant Parasitic Nematodes.  Nematodes are very specific and specialized in what they attack.  There are many types of specialized nematodes in the world attacking everything from plant and insects to human and livestock parasites.  

• A great example is heartworm in dogs.  This is a nematode which is spread by mosquito feeding.  The adult nematodes live in the dog’s heart, but the infective juveniles circulate in the dog’s bloodstream so they can be picked up by feeding mosquitos.  Infected mosquitos spread the parasite by feeding on uninfected dogs. The Heartworm nematode only infects canines which include dogs, coyotes and wolves.

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How do Biocontrol Nematodes find soil insect hosts?

• Biocontrol nematodes move through the soil on the water film on the soil particles by swimming.  They locate insect hosts by following the CO₂ gradient present in the soil from insect respiration.  Some soil insects have evolved to only breath every 30 min to try to hide from attacking Biocontrol Nematodes.

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How do Biocontrol nematodes kill their insect hosts?

• After Biocontrol Nematodes find their host, they enter the insect primarily through their breathing holes (spiracles).  

• Upon entering the insect, the attacking nematode releases a chemical to suppress the insect’s immune system and releases a specialized bacteria.  The bacteria rapidly multiplies, kills the insect, and preserves the insect cadaver with antibiotic-like substances.  

• The Biocontrol Nematodes then multiply inside the insect cadaver and feed on the nutrient soup.  When the food resources are used up, the new infective juveniles burst out of the old cadaver and begin searching for new insect host (prey) to repeat the cycle.