Contributed by:
Chimera
Thanks to:
Bunz Submitted: 07-19-2003
Images archived: 2003
Introduction
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| Image by: Green
Shaman |
Let me first
start out by offering you my sympathies... mites are one
of the worst pests you can encounter while growing
cannabis. They can reproduce at a phenomenal rate and
easily have the potential to ruin your flowering crop,
nay all your plant material IF you aren't vigilant about
getting rid of them.
Scared yet? You should be!
Hopefully this will wake you to the seriousness of the
situation; trust me you don't want to see a full blown
mite infestation. Not a pretty site. That having been
said, if you take care and understand the life cycle of
the mites, you should be able to rid yourself of them
quite easily.
The Environment
Mites have a life cycle that varies directly
with the environment... in a very hot, dry climate they
can complete a life cycle in a few weeks. If the
environment is cooler, and has more humidity, it can
take them over a month to hatch, mature and leave their
own offspring for the next wave of attacks on your
plants.
This is very important to understand,
because it's easier to destroy the population if there
aren't new ones popping up as fast as you can kill them.
So your first goal is to make the environment
less hospitable for the evils... drop the temps as low
as possible, and increase the humidity in your grow
chambers. An evaporative cooler should help.... this can
be as simple as a bucket with a fan pointing across the
water. Stale air is a no no as well, so get some good
fans constantly blowing across your plants (making it
very difficult for mites to lay their eggs) and increase
the ventilation if possible... depending on your setup,
this should also help drop the temps, but may decrease
overall humidity.
Biological Controls
You can go bio and use predatory mites.
Phytoseiulus persimillis is a voracious mite that feeds
on the evil mites, but won't eat your plants. When
they've eaten all the mites they can find, they run out
of food and die.
If you choose to go this route,
use one of the chemical sprays mentioned below (to knock
down the spotted mite population), but discontinue it's
use a week before introducing the predators; which are
themselves susceptible to the chemical sprays.
*Studies have shown that mites were able to
elude the persimillis by hiding in various nooks and
crannies around the garden, only to return to and take
over again when all the predators had died.
IF
you do use predators, a time-release is recommended...
add another dose to your plants each week for a month
just to make sure you've got some fresh predators to
hunt down any re-occurring mites that have been missed.
The predator mites will eat all life stages of evil
mite, from egg to adult. Adding predators can get
expensive; only the truly organic tend to use this
route.
Check online to find a cheap source of
predators; a Google search for "predatory spider mites
Phytoseiulus persimillis" should yield numerous places
to purchase.
Environmental considerations for
predator mites: The environment plays a big
role in biological predator mite control. In general,
?evil? mites prefer a HOT + DRY climate; the predators
prefer a COLD + HUMID climate.
If you put the
preds in a hot dry climate, the evil mites will out
reproduce them, and the predators won't reproduce fast
enough to kill them all. Same opposite for a
colder/humid room... the predators will easily out
reproduce the evils, and will have a much easier time of
taking care of the problem.
Introducing
predators to a flowering (12/12 light cycle) chamber is
essentially futile according to leading cannabis
researchers... the predators seem to just go to sleep.
They are more suited to the longer light cycle in a veg
room.
Chemical sprays Spraying
daily with water is really hinders the spotted mite's
reproduction.
There are many sprays that will
kill spider mites. Kelthane, Malathion, Neem oil,
pyrethrum based sprays.... the list goes on and on.
There is a product called AVID which is sold
illegally under the counter in many hydro stores. AVID
is similar to a systemic; it is translaminar. The safety
of AVID in cannabis and breakdown periods in leaf tissue
have never been shown adequately IMO, so I don't use it
nor recommend its use to anyone. NEVER use AVID in
flowering, if you feel you need to use it at all.
I've had great results using the 'softer'
pyrethrum based products. Pyrethrum is a natural
miticide produced by flowers in the chrysanthemum
family, it works against all the different mite
populations. Repeated treatment is key; most of the
sprays are unable to penetrate to the eggs; so you need
to re-apply the spray to take care of the hatched eggs
before they have a chance to lay more eggs themselves.
Spray application: Get yourself a
quality pressure sprayer (a separate container and a
wand type are the best) at home depot or Canadian Tire
etc. The wand allows you to easily get under the leaves
where the mites spend most of their time sucking the
juices from your babies.
I highly recommend two
product by 'Safers': EndAll and Trounce.
The active
ingredient in both is pyrethrum, but Endall is based on
canola oil, Trounce is based on soap and alcohol. Get
the Endall and Trounce concentrate bottles, mix your own
spray from these at home... it's much cheaper, and you
will be able to use your own sprayer.
Note:
Safer's insecticidal soap is pretty much the same as
Trounce. Trounce contains alcohol and pyrethrum as well,
which will further help kill the bugs.
I like
the Endall because it coats the entire surfaces of the
leaves well, and seems to penetrate the eggs and kills
some of them, where as the trounce doesn't seem to kill
the eggs.
I like to apply Endall generously
first (Day 1), and let it soak overnight, then rinse
with plain water in the morning. Twice a day (if
possible) on Days 2-5 spray the plants down using the
same pressure sprayer with plain water... make sure you
get both top and bottoms of the leaves each time.
On Day 5 mix a batch of the trounce up and
again, spray before lights out. Rinse in the morning,
and on days 6-10 spray twice daily with plain water.
Day 10- repeat the cycle
This should
have killed all the mites on the plants, unless your
population is resistant to pyrethrum. If they are
resistant, you might substitute a harsher chemical (ie
kelthane (flinch) or Malathion (flinch) ) for the second
application of Endall.
Spray tips:
Always read the label for mixing direction, and
never spray closer to harvest than recommended by the
manufacturer (Never use a product recommended for
ornamentals only... make sure it is safe for use on food
crops.).
These types of sprays are contact
sprays... if the solution doesn't come into contact with
the pest, the pest won't die!! This is why it is so
important to use a good sprayer and make sure you coat
the entire plant- top and bottom of the leaves. Even
spray the surface of the medium.
The mites MUST come
into contact with the spray o be killed. Mite eggs are
resistant and won't be destroyed, so you'll need to
reapply the spray the before the hatched eggs can lay
their own eggs.
[Editor?s note: spot spray if
you have never used the chemical before to prevent
damage to your entire crop. Never spray with HIDs on,
and use appropriate protective gear]
Other
homemade chemicals If you smoke cigarettes,
you can also make a spray with a small amount of dish
soap, and some tobacco. The nicotine is extremely toxic,
and will kill the bugs if they come in contact with it.
Break a bunch of cigarettes up and soak the tobacco in
water overnight. Beware of the possibility of TMV
(tobacco mosaic virus), unless you boil your solution
for ~20 minutes (after adding the tobacco) to kill the
virus. Let cool, add your few drops of detergent and
voila. Strain it, spray it.
You can also add
some types of hot pepper powder (cayenne etc), or if you
have access to chrysanthemums... get a bunch, remove all
the petals and blend them in a blender with water.
Strain, and add to your soapy solution. This should work
also.
Room sterilization and other tips:
Bug bomb your rooms (Dr Doom etc) between crops,
or whenever you can get the plants out, if possible.
It is also very important to clean out your
growth chambers.
I've used a second pressure sprayer
filled with a strong bleach/water mix... the hotter the
water the better. Remove all your plants from the room
(After first spraying with endall- you don't want to
bring bugs out of the chamber) and completely soak the
chamber in the bleach/water spray. Get all the walls,
the entire floor and don't forget the cracks in the
walls or the base of the trim. Allow this to air dry.
Repeat if possible. Spray the plants down again with
your Endall solution before you put them back in, just
in case you missed a few the first spray.
Don?t
introduce mites to your room! Check other houseplants
for mites, and treat them as well if infected. Pets
should not be allowed into the garden, especially if
they are outdoor pets. Same goes for you... change your
clothes and shoes before working on you garden, and
never use the same tools as you use for your outdoor
veggies or houseplants.
Be particularly careful
about changing your clothes/shoes if you've been walking
in the woods, have been to a nursery or a garden store/
hydro store. You don't want to bring someone else's
problem home on your clothes and introduce it to you
garden!
