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Beneficial (entomopathogenic) Nematodes
Steinernema
sp.
Heterorhabditis sp. |
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What is a nematode? They
are the most numerous multicellular animals on earth; in fact there are
many thousands of individual nematodes in every single handful of garden
soil. They are microscopic non-segmented worms.
There are many kinds of nematodes, but when
it comes to gardening you can break them down into two categories. The bad
nematodes can parasitize roots of plants, or cause foliar damage. These
“plant parasitic” nematodes can be of great concern (to you and the state
inspectors) if you are shipping plants with soil across state lines. Then
there are the good or beneficial ones; these are the nematodes that are
used in modern biological control to combat a
wide variety of insect pests.
Where to buy
beneficial nematodes
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Beneficial Nematode
Steinernema feltiae
Photo by Jim Cate, Ph.D
More about beneficial nematodes... |
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History Using
nematodes for biological control is not a recent development. Ever since
the 17th century, nematodes have been known to parasitize
insects. In 1929, researchers Glaser and Fox identified and reared
nematodes to potentially control grubs of the Japanese beetle. One would
think this would have set off an era of biological control, but with the
development of more economical insecticides, this research was to be put
on hold. Fast-forward to today, and the labs are once again busy.
Environmental contamination, the de-registration of many commonly used
chemicals, and resistance management concerns are causing researchers to
look at nematodes once again, with promising results. |
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Biology- Beneficial nematodes can be broken down into 2 ways
in relation to how they hunt prey. There are the “ambushers” (which
include the Steinernema spp). This group
of nematodes will sit and wait for an insect host to move by, and then
move to force their way into the hosts’ body. They are very effective
against pests that are moving around on the soil surface, such as
cutworms, fungus gnats and others. On the other hand there are the
“Cruisers” that will move around actively searching for hosts. They are
usually found deeper in the soil profile attacking many types of grubs.
These are normally in the genus Heterorhabditis spp.
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Frequently Asked Questions
About Commercially Produced
Beneficial Nematodes
Click here
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NEMATODE SPECIES COMMERCIALLY
AVAILABLE
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Nematode name |
Controls |
Comments |
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Heterorhabditis bacteriophora |
Weevils and other beetle grubs that live in the
soil including Japanese beetle, Masked chaffer, Black vine weevil,
Strawberry root weevil, Flea Beetle and more |
One of the oldest known and best of the insect
parasitic nematodes |
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Heterorhabditis indica |
Citrus root weevil group, May/June beetles,
Banana moth, Mole Crickets, Masked chaffer |
A species of nematode newly discovered in the
U.S., particularly suited for use in subtropical soils and
environments |
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Heterorhabditis
marelatus
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Weevils and other beetle grubs that live in the
soil including Japanese beetle, Masked chaffer, Black vine weevil,
Strawberry root weevil, Flea Beetle and more |
Some what more cold tolerant then
Heterorhabditis bacteriophora |
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Steinernema carpocapsae |
Fleas, Armyworm, Cutworm, Fruit fly, Sod
webworm, Beet armyworm |
Ambusher
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Steinernema feltiae |
Fungus gnats, Fruit flies, Tobacco cutworm,
Shore flies, Onion maggot, and more |
Ambusher |
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Steinernema scapterisci |
Mole Crickets |
In 1985 S. scapterisci was brought from
Uruguay to Florida |
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Where to buy beneficial nematodes
Testing Beneficial Nematodes To
See If They Are Alive
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Tools needed:
nematodes, water, small dish, hand lens (10x or better) or microscope |
- Place a small
sample of nematodes on a small plate or petri dish.
- Put 1 drop of
water on sample.
- Wait about 10
minutes, and then look at with lens or microscope.
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ALIVE!
Snake-like movement, or nematodes
curling in circles (like doughnuts).
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DEAD
Straight
arrow-like appearance. You can expect to see some dead
(most companies pack extra to compensate)
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See photo to right |
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