Wednesday, 10 July 2013

Ants and Aphids - You Scratch my Back and I'll Scratch Yours

Seems a fairly simple arrangement doesn't it.  It's one that's called a symbiotic relationship and if we could all just get along like these two insects then the world would be a happier place.

At a recent workshop by Sustainable Gardening Australia to launch our council's booklet called Home Harvest, Helen from SGA kept us all in stitches as she went through her very entertaining presentation on sustainable organic gardening.  You know you have reached your comedic peak when very polite Asian gentlemen go from polite giggles behind their hand to laughing uproariously like everyone else.

As usual, its not the structured presentation that you hear all the good bits.   Its the "in betweens", the conversation over cupcakes and the questions and answers that came fast and openly throughout the 5 hrs.  So during a discussion on the need to water our gardens during winter and create biodiversity to allow nature to take care of nature, Helen asked the question.  "Do we have ants in our garden"?  Well Yes, i actually do but what has that to do with moisture?  Well, here's the drum.  There is no such thing as a low water veggie patch or fruit trees for that matter.  They can be made more drought tolerant or water aware but if you don't water them then the plants will be weakened and be open to predators and disease and the harvest will lack flavor.  That's it.  No way out of it, you must water your garden.  All year.  Here is the big 3 - Airate your soil by forking the soil, use gypsum powder regularly (for those of us who live on clay flats), water deeply and mulch, mulch, mulch. While you are at it, throw in some mushroom compost from Soilworx (Hoppers Crossing and Deer Park).  This is an unpaid advertisement.  It really is good stuff and you might get the odd mushroom popping up.

The most common evidence of  lack of moisture in your garden will be the presence of ants followed by an outbreak of aphids.  Hello! That would be my veggie patch last season.  Aphids everywhere.  I didn't really notice the ants as they weren't the ones chomping away at my first ever crop.  I can tell you that they were there anyway because where there are aphids, there are ants, working away together to destroy all your hard grown produce.  What a team.

Ants don't do anything for fun.  There is no fun for ants, its all work work work.  So when you see them very busy running up your trellises or up your trees and veggies they are usually taking baby aphids that they look after in their nests in the ground, holding them in their pincers, to deposit them on the new fresh growth.

So what's in this relationship for the ant?  Its called honeydew and it is excreted by the aphid and used as food by the ants.  Honeydew is like crack for ants.  They cannot get enough of it. So they not only transport the baby aphids to the their food but they will protect them by fighting off all aphids predators.  This honeydew also causes Sooty Mold which looks like dusty charcoal on your plant.

Ant on Crack - Honeydew
Sooty Mold

There is an old wives tale that if we see ants running around like mad that it is going to rain.  Its true.  They cannot build their nest where it is wet.  They have to move.
Lightbulb Moment - 1
You mean, if i keep my soil moist, i wont have ants which means the aphids wont have free transport and their own personal security team and therefore our friends of the garden (ladybugs etc) can eat the aphids and Ta Da, problem solved?  You got it.

Ants will tell you whats going on in your garden.  They are like the canary down the mine shaft.  If you manage the ants you can get rid of a lot of common problems in the garden.

Tansy plant
If you have ants that are persistent, the herb TANSY is a great ant repellent.   Grow it in a big pot (as it like to get away) and pull the leaves off and mix with your mulch. Particularly in pots that dry out quickly. This is an example of nature helping nature.  We just get in the way and create unsustainable environments that stop Mother Earth doing her thing.

I went to the big green warehouse (inside joke) and asked for Tansy.  They didn't know what it was.  I explained what my Horticulturalist/Soil Scientist presenter extraordinaire told me and they just looked at me blankly.  Hence, i am still looking for a Tansy plant.

Lightbulb Moment - 2
Lightbulb Moment 2

Another way to get rid of aphids is to squish them and drop them on the ground in the bed.  The dead aphids will tell the other aphids that this area is death valley and they will move on.  Makes sense, doesn't it?

Hint-  This smell of death also works for possums.  Hang a stocking sock in a tree or from rafters filled with blood and bone.  They respond to smell.  This also works with Lapsang Souchong Tea (chinese herbal).  Apparently it stinks so brew up a strong brew and spray it along the access path (along top of fence, or tree branch).  Apply either method for 4-5 weeks and their habit will be broken and they will go elsewhere.  Where? Who cares.  

Hint 2 - Bats are difficult to get rid of but try hanging CD's as it affects their sonar.  It bounces off the CD and affects their depth perception. Heavy Metal works best i am told.  Personally, i would put the country and western ones out (if i had any) as they are not much good for anything else.  (Just my opinion - its MY blog)

I did tell you that all the good stuff comes out all over the place.  Such a wealth of knowledge.  I guess if you run a nursery, frequently do presentations to budding gardeners that propose all manner of questions and can back that up with a few degrees, then you are going to know some stuff.

Other Methods of Aphid Control

Lace Bug Control                     Lacewing PDF

Check out link as you can buy punnets of Lacewing Eggs that you release at the beginning of the growing season.  I'm not sure if introducing a bug that's not normally in your environment is a good idea but check it out.  I am not an authority on this subject, so Google it.

Ladybugs - there are over 400 varieties of ladybugs in Australia and they eat aphids voraciously.  So how do you get ladybugs or lady beetles in your garden?  Do not use pesticides in the garden and provide them with plenty of food like flower nectar and pollen.  The presence of aphids will keep them there.

Rubbing them off with fingers (See Lightbulb Moment 2 above) or squirting them off with water.

Soap Sprays - use horticultural soap or soap made of vegetable oils.   Helen was adamant that the sprays that many make up with dishwashing detergent and garlic should never be used as they contain surfactants (the degreaser element in detergents) that harm worms and other good bugs that breathe through their skin.

Lime Sulphur for serious outbreaks.  Please Google.   PH of 11  - so be very careful.

So, there you have it.  All i know about ants and aphids.  Though i don't want either in my garden you got to love the way nature works.

Thanks for visiting Living In The Land of Oz


  1. Gypsum is only useful for certain types of clay to be honest. Massive clay, like ours, isn't fooled by it. 200mm down we have massive yellow clay that sucks up the water and heaves the houses around like so much flotsum and jetsam if you don't keep the immediate vicinity watered. Water is too precious to be wasted willy nilly and the idea of building worm water wicked garden beds is a good one to limit the amount of water being used to produce our food. The downside is that they are a lot more expensive to build. Sometimes this food production gives you a headache...and those ants and aphids have a third's called Powdery Mildew and they are a threesome that can really get under your skin if you don't remove one of the triangle and render them less dangerous. My money is on the aphids as they are the main problem! Once they are out of the picture, the ants and the powdery mildew seem to head off to greener (more lush) pastures ;). You can get tansy seed, if you grow it yourself you can share the love :). You can blast aphids off your foliage with a hose. Aphids suck but they can't hang on all that well so you get the last laugh if you are vigilant. The possums eat all of the tender shoots before the aphids can get to them so I suppose that's a benefit to possums? By the way, our possums could care less about blood and bone, Lapsang souchong (although why are you giving it to the possums, it's delicious!) or anything really. I could hang dead possums all over the place and they would still come in the night to wreak their havoc. The 13 feral cats that are in various stages of starvation do their best to cull them but still they come...just like the Martians from war of the worlds...

  2. I shall have to look for the ents in the greenhouse then as aphids on broccoli I have a plenty. I did give it all a good fertilising water the other day though but it's all well due for another water. It's just been hard when the hose is frozen solid every morning. ;)
    Great post and thanks for the info. :) And as for the big green warehouse, thier nursery is pretty pathetic. If you don't want to grow from seed (you can get the seeds from Diggers or even eBay) then I'd check a real nursery in the herbs section. :)

  3. Thanks Narf7 for feedback. I wish i had Helen's email for feedback response but alas she was but a dream. I was actually going to do a post of gypsum because she raves about it so maybe i will try and find her. She was one of those people that you instantly like and wouldnt mind spending more time with. She lives in a court in West Footscray and they have take down fences and combined front gardens, providing for each other. One person has chooks etc etc. Sound pretty cool doesnt it.

  4. Hey there Lynda D, what a great blog! I particularly enjoyed this post....mainly because I'm in it! I thought it best to post a bit of follow up on the post here and the comments. Your reader is correct - gypsum doesn't work on all clay soils, only sodic clay soils. But how do we know a soil is sodic? And why would I recommend gypsum to be applied to clay soils if they haven't been tested for sodicity? Well, first things first - if you need to know whether your soil is "sodic" or not, and whether it will be responsive to gypsum, there is a very simple backyard test we can do.
    1: Grab some dry clay soil from various areas of the garden - don't just use the surface, dig down a little bit (about 15cm)
    2: These aggregates of soil need to be about 5mm to 1cm in diameter
    3:Pop 50ml of either rain water, distilled or bottled water gently into clean, dry, individual trays.
    4:Gently place one aggregate into the centre of tray or container and allow to stand for 24 hours without disturbance. 5:Have a look at how the clay has behaved, because 3 reactions are possible. If the clay particles float up into the water making it cloudy – they are repelling each other and this is dispersion. If the water remains clear but the aggregates collapse in a heap- this is known as slaking. Thirdly, the aggregate remains as it is – this is a ‘good’ clay for the garden.

    Dispersive soils are sodic (about 30 - 35% of Oz soils) - treat these with gypsum. Soils that slake should be treated with organic matter (think composts, straw mulches etc). The third type - keep these maintained with organic matter.

    What about those soils that aren't sodic and have a bit of gypsum? Gypsum stills adds value as it adds calcium to the soil, which is a super essential nutrient in the healthy form and function of fruits. It also helps prevent a number of disorders, like Blossom End Rot. I love the stuff - it's pH neutral, full of good stuff, and works a treat over time on sodic clay.

    As for the ants, powdery mildew and aphids "threesome" mentioned in a previous comment - I reckon the 3 of them hanging out in your garden together are a coincidence more than a tryst. Ants and aphids are completly symbiotic - manage the ants, you'll minimise the aphids. The powdery mildew on the other hand is a fungal issue, caused by poor air circulation, moisture on foilage, and particular air temperatures. I reckon if you are seeing all 3 at once, it's an environmental/plant stress thing, rather than a group love-in.

    Oh, and if you're looking for Tansy.....let me know!


Please leave a comment. I enjoy making connections with my readers. Hope you enjoyed your visit.