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| Praying mantis or mantid |
Q. I’m starting to see stinkbugs or squash bugs on a few squash
leaves as well as the eggs on the undersides of the leaves. I know how fast
those hungry buggers can suck the life out of cukes, squash, melons or whatever
sounds good to them. This year I bought some praying mantis
eggs/nest. It’s impossible to see when they hatch and leave home so I
just thought they died. Imagine my surprise
to now be finding baby
mantis’s in my front and back yard….on the very same plants the squash bugs
are hitting.
So here’s my question. To spray for the bugs or hope the praying mantis’
will feast on the squash bug buffet?
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| Squash bugs a close relative of stinkbugs and leaf footed plant bug. |
A. That’s a really
good question and it is one of the major difficulties we face when we try to
manage our garden and fruit trees organically or as organically as possible.
You have introduced an insect predator into your garden to help keep some of
the “bad bugs” under control rather than to use pesticides. It is one
of the cornerstones of integrated pest management or IPM.
We should also be
realistic about what praying mantis can and cannot do. They are not focusing on
“bad guys” to help you, they are just looking for a meal. Their meals
include “good bugs” and “bad bugs”.
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| Bt insecticide |
Using beneficial insects like mantids works
great with some pesticides approved for organic production and it does not work
well in combination with others. For instance, if we use a pesticide permitted in organic
production that targets a certain pest while not harming others it can work
fine.
An example is using Bt that kills only the larva or worms of moths and
butterflies but we want to protect the praying mantis. It is totally safe for
the praying mantis since it targets only the worms or larva of moths and
butterflies. However, if we are realistic, it also kills the larva of
butterflies which are not plant pests for our gardens.
insecticidal soap, which is also recommended in organic production, and apply
it to our vegetables or fruit trees, we are applying it is an
“indiscriminate killer”; it will kill any insect on contact, squash
bugs, leaf footed plant bugs, aphids, honeybees as well as praying mantis.
When
we choose to use an “indiscriminate killers” but want to keep
beneficials, like praying mantis, from getting harmed, then we must direct the
spray on the insects we want to kill and avoid spraying the ones we do not want
to harm.
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| One of the insecticidal soaps |
This requires a lot of plant inspection on your part; looking for,
identifying and targeting the “bad bugs” with the spray. Focusing on
the use of beneficial insects as your primary method of controlling “bad
bugs” limits your ability to use pesticides. You must either not use
pesticides or select pesticides which will not harm the beneficial insects or
direct any pesticide sprays so that they come in contact only with “bad
bugs”.
to use these indiscriminate killers, such as insecticidal soaps, to keep bad
insects under control and realize you will have “collateral damage”.
The “collateral damage” which occurs is the killing of good bugs and
bad bugs with the hope that the good bugs will recover after the spraying is
over. You also select “organic” pesticides that do as little damage
to the general insect population as possible. This type of spray program limits
the use of beneficial insects for any long-term control. It is really a
“spray and pray” program.
mantids. They will migrate to other parts of your landscape as well as your
neighbors. Visit and inspect your garden and fruit trees often. Use plants
sprays when “bad bugs” are getting out of control and target your
sprays on these “bad bugs”.