Question
Hello, I have a serious issue with spider mites.  For the last 5 years spider mites have taken over my Butterfly Bushes.  Its a daily ritual to keep these things at bay.  My local nursery  recommended using an Organic agent, Bionide Mite.  This seems to work for a week or two but they come back in full force.  I live just outside of Washington DC where the weather has been dry, hot and humid.  I have read some info regarding ladybugs and predator mites.  Which would you recommend?  

More importantly is there anything that can be done while spider mites are dormant or at the beginning of spring to destroy these pests before they become active.

Regards,

Craig Rupert

Answer
SPIDER MITES?  Tetranychus urticae?  I can definitely help you with this problem.  Have a seat, Craig.  Pour yourself a glass of cold Lemonade.

First, I have to ask: Are you sure?  Do you know what these dust-sized specks look like?

There's a black and white photo of an afflicted leaf at the Virginia Extension Entomology website:

www.ext.vt.edu/pubs/entomology/444-221/444-221.html

Please confirm.  No sense treating for the Flu if you have a broken leg.

Yes?  My friend, the Virginia Coop people tells us that YOUR GARDEN is at the TOP of the list for dinner reservations for Two Spotted Spider Mites:  'More than 180 host plants have been recorded for this species.'

Leaves turn pale as the Mites suck out all the chlorophyll and plant juices.  Their favorite seat at this restaurant is the table next to the Amino Acids, set up between leaf midrib and veins.

Summer weather conditions contribute to the bloom of these Bad Bugs.  Their damage accelerates as temps rise.  For one thing, the Mites get hungrier; dry air increases evaporation of excreta.  It also alters leaf chemistry that makes plants more nutritious for Mites.

The Colorado Coop Extension website explains everything:

'High temperatures (up to 100 degrees F) decrease the lifecycle from three weeks to a mere 5 days and low humidity allows the Mites to more easily remove waste products from their bodies via evaporation, thus enhancing feeding and reproduction.'

See that?

FIVE DAYS!  No wonder you felt like your Garden was under attack.

You can read it online:

http://www.colostate.edu/Depts/CoopExt/4DMG/Pests/spidmite.htm

They list some little known bonuses with these Mites as well: 'Spider Mites are a known source of allergens causing Asthma, Hay Fever, and Contact Urticaria.'  How抯 your breathing?  Any strange skin rashes, Craig?  Been sneezing a little more than usual?

Now, under normal conditions, your Garden is packed with plenty of Predators and Fungi that are hostile to these pests.  This is one reason they appeared 慸ormant?to you just a month ago.  Among the Natural Predators back then, Colorado points, there was 'a Fungus disease that is present when temperatures are below 85 degrees F and relative humidity is high.'

First, let's clear up a few things.

Was this Bonide Mite and Insect Spray you used?  Here is the OSHA Hazardous Materials sheet on this product:

http://www.bonideproducts.com/msds/pdf/mitespry.pdf

I love the internet.

Malathion.  Lindane.  Carbaryl.  Kelthane.  Everything but radioactive isotopes.

The Bonide Products Website lists all their products.  They have an impressive list of prominent gardening personalities who dish out advice on the media, Ralph Snodsmith and a dozen other people, blithely pushing Bonide into the liver cells of pets, children and their good neighbors everywhere:

http://www.bonideproducts.com/

If you did get a line at your nursery center that this is 'organic', go back to the man or woman who told you that and give them a piece of my mind.  I am so irritated right now I want to throw my washing machine out the window.  Excuse me while I bang my head against the wall.

*  *  *  *  *

O.K.  Where were we.

Oh, yes.  Agent Orange.  Craig, my friend, this was totally unnecessary.  And as you know, it does not work.

Let's also go back to your description of your weather.  Craig, you described it as 'dry, hot and humid'.  The Hot part, I get.  But is it Dry?  Or is it Humid?

Don't answer that!  I already know.

Because you have Spider Mites.  And Spider Mites means one thing and one thing only: HOT and DRY.

Spider Mites, the bane of Winter windowsills everywhere.

Weather Underground says last month's weather in zipcode 20001 was typically hot.   It hardly rained.  Which made it dry enough for Spider Mites to fluorish.  On your wettest day, in the middle of the month, when you got a ton of rain for a few hours, the humidity reached 93 percent.  But the weatherman also recorded a low around 32 percent for that month.  The average lack of moisture in your air is just enough to make Natural Controls of your Spider Mite population miserable AND make the Spider Mite population erupt.  But YOUR actions sealed the deal -- with the best of intentions -- by poisoning the drought-stressed Natural Controls until they were all but eliminated.

The interesting thing about this problem (a textbook Spider Mites situation, I assure you) is that you specifically ask, 'Is there anything that can be done while Spider Mites are dormant...?'  Let's take a look again at the Garden, back in the Spring, when the Spider Mites were NOT a problem.  Virginia Cooperative Extension makes some interesting points about why and how we wake up one day to a population explosion of these pests.  They note that Ladybeetles, predatory Thrips, and Mite-eating Mites offer 憇ome?control, but they cannot keep up with the pace.  Next thing you know, Mites are everywhere.

That's SO important.  

Why?

Because, sir, even if your entire Garden is organic -- and God I hope it is ?Ladybugs and fellow predators CANNOT eat these Bad Bugs fast enough when the air is hot and dry.  The Spider Mites just multiply way too fast.

Like if you were making pancakes for breakfast and the kids were talking, you would just pile up all those pancakes until there was no room to sit down.

Same problem with the Spider Mites and the Ladybugs that love to eat them.  And I do love Ladybugs.

Spider Mites start building families when temperatures hit 80 degrees F.  It takes 5 days for a Mite to hatch and grow up.  FIVE DAYS!  And they live for a month!  EACH hatched Mite begins laying 300 eggs!  Poof!  You can see how Spider Mites are poised to take over the world when it gets hot and stops raining.

That's a LOT of pancakes, Craig.

Virginia Extension makes an important point: "Insecticides are not effective on Mites and some, especially Carbaryl (Sevin), result in increased Mite damage by killing their natural enemies.'  PRINT THIS OUT AND SHOW IT TO THE SALESPERSON WHO SOLD YOU BONIDE MITE.  Get your money back.

Even those non-Organic Bug Sprays that DO work will kill the Butterflies, the Ladybugs, the Worms, and eventually YOU.

Watering is a critical part of the battle against these Mites.  And if you're thinking of treating your Buddleia to a chemical snack to help it recover, forget it.  Fertilizing them at this point just sweetens the deal for the Mites -- especially with Nitrogen formulas -- by generating more of the delicious Amino Acids that make up the green plant cells.

You could get begin to get rid of these Mites with a few containers of Ladybugs and Lacewings, which if you were here on Long Island you could pick up at Hick's Nursery on Jericho Turnpike in Westbury.  The Colorado Fact Sheet on Spider Mites states that 'small, dark-colored Lady Beetles known as Spider Mite Destroyers (Stethorus species) are specialized predators of Spider Mites.'  Pirate Bugs, Bigeyed Bugs and predatory Thrips are touted as 'important natural enemies.'  

But like that kitchen with the pancakes, you'll need a lot of hungry bugs to keep up with Mite production at this point.  You'll be CUTTING EDGE if you stock up on Phytoseiulus persimilis and Neoseiulus fallacis (aka Amblyseius fallacis), predatory Mites that eat Tetranychus urticae for dinner.  Predatory Mites are AMAZING.

The downside of the predatory Mites is that they need humidity to flourish.  When it抯 too dry,  their eggs shrivel up and die, and adults get weak and lose their appetite.  Predatory Mites also can't survive through our Winters, at least here in Zone 7.  But they usually wipe out the Spider Mites population so effectively that they starve before they freeze.  That's how good they are.  A 100 percent wipeout of ALL your Garden's Spider Mites!  No Chemical Spray will give you those results.

Here's the Cornell Cooperative Extension cheat sheet on Phytoseiulus persimilis:

http://www.nysaes.cornell.edu/ent/biocontrol/predators/phytoseiulus_persimilis.h...

The Cornell authorities emphasize, as noted earlier, that the predators need air moisture to survive -- at least 60 percent humidity.  'This species is a specialized predator of web-spinning Spider Mites such as the Two-spotted Spider Mite.  In fact, P persimilis feeds, reproduces, and completes development only on Mites in the subfamily Tetranychinae ...'

Neoseiulus fallacis gets its own cheat sheet at Cornell:

http://www.nysaes.cornell.edu/ent/biocontrol/predators/neofall.html

'This predaceous Mite has a strong preference for pest Mite species and will travel from tree to tree searching for them. It is found across the continental United States...Because N. fallacis is a voracious consumer of mites and because its population increases quickly in relation to its prey, it can overtake an expanding pest population.'

Cornell points out, 'The habit of N. fallacis to overwinter in crevices can be used to advantage in the early spring with a pre-bloom horticultural oil application. This greatly reduces the number of European Red Mite eggs while not affecting predatory Mite populations.'

The 'European Red Mite' they refer to is a relative of your pest.  Both are classified as 'Tetranychid Mites'.

Worst thing you can do, they say, is to spray your plants with stuff like that Bonide you bought.

'Pest Mite problems are most common where pesticides are heavily used because predatory Mite populations are killed along with target species.  It may take up to three years to establish a population of predators high enough to control pest Mites.'  This is the surest way you can fast-forward to the panic button.

Craig, take some action here.  Tell your local nursery to get with the program.

They don't like to buy these Beneficials because the shelf life is very short, the profit margin is slim, and they've never heard of them.  Nevertheless, Scientists consider these THE MOST SUCCESSFUL BIOLOGICAL CONTROL AGENTS ON THE MARKET today.  You will probably have to purchase them by Mail Order.  Well known suppliers include:

Buglogical Control Systems
www.buglogical.com

Worm's Way
www.wormsway.com

Kuida Agricultural Supply Company
PO Box 2598, Salinas, CA 93902 - 408-758-9914

Growquest
www.growquest.com/phytoseiulus_persimilis.htm

Futuregarden
www.futuregarden.com/environmental

There are lots of others.

So if you have Spider Mites in Washington DC, it is likely that some predators will have to be replaced every Summer.

For this month, the weather in your region is forecast to be slightly wetter.  Humidity will be higher -- borderline for predatory Mites.  You may be able to boost it with a gentle spray several times a day with the garden hose, to keep the leaves moist and raise the comfort level of the delicate predator babies and their eggs long enough for them to search and destroy a LOT of Tetranychus.

While you're waiting for delivery on Good Bugs, Spider Mites can be treated with Water.  That's right.  Good old H20 will wash those mites away while you get the other things you need.  Ladybugs and Lacewings -- Plan B -- will help.

Rinse them 2x or 3x a day.  Wash the undersides of the leaves gently. You will wash all the Spider Mites and their children away.  Then rush back inside and let your fingers do the walking -- order some biological control agents.
Your future biological control options are encouraging.  Researchers at the University of Maryland post a report, 態iological Control Options for Spider Mites in the Greenhouse? where they studied strains of the Spider Mite Fungus 態eauveria bassiana?  The JW-1 Strain, which is currently sold to the greenhouse market as a product called 慛aturalis-0?by Troy BioSciences, was most successful:
慣he mode of action of the Fungus begins with the attachment of Fungal spores, or conidia, to the insect cuticle.  The spores germinate and produce infection structures which penetrate the pest's cuticle. The Fungus then grows into the body of the pest.  If the Fungus can overcome the pest's natural immune system, it proliferates in the body and kills the host.  It is key that sufficient numbers of viable spores contact the pest for infection to occur, so excellent spray coverage is essential. The pest picks up the Fungus at spraying time or when it moves over the treated leaf surface.?br>
Better living through Biochemistry and Microbiology.  Very exciting.

Any questions?

And now, please pass the Lemonade.