Do nematodes control above-ground pests?
Written by
Michael Sullivan
Reviewed by
Prof. Charles Hartman, Ph.D.Above-ground pests, being outside of their soil habitat, will not be affected by beneficial nematodes. Beneficial nematodes are microscopic predators that target pests in the larval or pupal stage in the soil. I learned this when I observed aphids still on the plants weeks after applying nematodes. When seeking comprehensive control, you need to start with nematodes and then implement above-ground measures to effectively handle pests.
Leaf-Eating Caterpillars
- Use Bacillus thuringiensis (Bt) sprays applied directly to foliage
- Apply during cool morning hours for maximum adhesion
- Reapply after heavy rain to maintain protection
Sap-Sucking Insects
- Release ladybugs or lacewings for aphid and scale control
- Use insecticidal soaps for immediate knockdown
- Apply neem oil as a preventative every 7-10 days
Flying Pests
- Install floating row covers before pests emerge
- Use yellow sticky traps for adult whiteflies and fungus gnats
- Introduce parasitic wasps for greenhouse environments
Establish a layered defense system in your garden. Address soil pests (grubs in this case) using nematodes. Deal with above-ground pests with  a spry solution for those pests. I use nematodes and apply a spray of Bt every week during the caterpillar season. With this two-pronged approach, I completely eradicated my cabbage worm infestation last summer.
Use your time strategically. Apply nematodes when the soil temperature is 55°F. Use above-ground controls as soon as you first notice the pest. For Japanese beetles, I will apply nematodes to the grubs in July, and then I will apply neem oil to the adults in August. This will break the life cycle of the pest.
Regularly monitor your pests to modify your approach as needed. Check leaves for chewing damage as a clue to above-ground pests. Look for larvae in the soil. Taking garden walks once a week allows me to spot problems early. Please keep a record of pest observations to identify what to look out for next season, just as I do with my gardening journal.
Read the full article: Beneficial Nematodes Garden Pest Control
