Beneficial Insects Part two 8/26/22

Beneficial Insects Part two 8/26/22

Posted by Mandy + Steve O'Shea on

  Last week we discussed big picture organics and the idea of trying to incorporate natural systems into the process of farming in order to reap the benefits of nature’s services while minimizing harm by reducing or eliminating human made inputs (You can read here!). In that vein, I promised to talk about how we did just that with our dahlia production and took a crop that used to be our most heavily sprayed and eliminated organic pesticides completely.

   Dahlias are amazing.  Dahlias are gorgeous.  Dahlias are delicious.  Every insect in Georgia wants to eat a dahlia .  Or better yet, all the dahlias.  For years we would plant in early Spring like all the textbooks advise.  We’d watch in fascination while our plants grew to 6-7 feet tall and started blooming in peony season.  We had some of the first dahlias to come in season in the country!  They were amazing!

  Amazement would eventually turn to dismay, then horror, as we became completely overwhelmed by every insect in Georgia.  Dahlias are expensive to grow.  The tubers are very expensive.  The loss of tubers to rot after planting is high in our hot and humid climate.  The labor costs to plant and weed and trellis them is high.  The labor cost to harvest is higher than other flowers as well.  So to find yourself having to throw out 9 out of every 10 flowers you harvest because it's been chewed to bits is just devastating and is not a viable business practice.

  To avoid such loss, we spent countless hours handpicking insects into buckets of soapy water, puffing diatomaceous earth onto the top and bottom of every leaf, spraying every organic pesticide we could find to try and calm the destruction.  Anything that worked, only worked for a few days.  Then the demons came roaring back with a vengeance.

   We debated giving up every year.  We lost so much time and money trying to grow dahlias.  We spent hours and hours talking to other farmers, researching forums, talking to authorities on the topic.  It all s eemed pretty hopeless to grow them for profit.

   I’m not even sure how it all coalesced at the same time, but Mandy and I both had some light bulbs go off about 6 years back.

  She surmised that if we bucked traditional wisdom and planted late, we might escape some of the worst damage.  The idea being that the plants were exposed to extreme heat in the summer and were therefore weakened by that stress, making them more susceptible to pests.  They were also prime habitat for populations of pests that used them as a hedonistic paradise of food and sex and just exploded in numbers in the sultry summer weather.  Effectively, we were breeding the thing we were trying to avoid and she changed everything so that we would plant many months later than anyone else.  This turned out to be a huge benefit to the plants and in my opinion, a brilliant innovation of hers.

   At the same time, I had been toying with using beneficial insects to prey on the worst of our pests.  Not only beneficial insects, but beneficial fungus as well. 

   I made 2 four foot tall pepper shakers, filled them up with milky spore powder (a fungus) and walked every inch of the farm spreading the dust on the ground.  Japanese beetles had been plaguing us for years and seemed to double in number from one year to the next.  

   The fungal powder is harmless to everything but the larvae of Japanese beetles.  The season after spreading it, their population had dropped a solid 70%.  So many flowers saved!!

   The next pests to deal with were Western Flower Thrips.  They are a tiny little nightmare.  I ended up using 2 types of predatory mites (stratiolaelaps and swirski)  and one predatious bug (Orius).  

   One type of mite is soil dwelling and attacks an early larval stage of thrips.  The other is leaf/stem dwelling, and attacks a later larval stage of thrips that lives and eats in the green portion of the plant.  The Orius bug flies from flower to flower and quickly darts between petals, spearing the thrips with its sharp proboscis and sucking the life out of tons of them per day.

   The combination of all 3, along with the shift in planting schedule, the Milky Spore fungus, and Organza bags on the more vulnerable blooms has shifted our losses of viable dahlia stems from 90% to somewhere closer to 10%.

   That’s about as good as it gets in farming.  We couldn’t be more thrilled with the results.  We don’t have a nuclear scenario and a completely sterile insect free zone.  We have an ecosystem with checks and balances to prevent any detrimental species from exploding in number and destroying our crop.  As a result we spend less time, less money, and create less harm to the land and all its inhabitants and we have tons of butterflies, moths, honeybees, spiders, wasps, lady beetles living amongst the flowers and the remaining thrips.

  Dynamic equilibrium.  I’ll take it.

  We've talked about these things on Instagram in the past and have gotten a few repeated questions that I'll address here:

"Can I overwinter dahlias in Georgia?"  Yes.  There is some potential for frost damage and increased odds of rot due to wet soil, but you can do it, though we don't recommend it.  We used to do it and it only resulted in the problems I mentioned above.

“What can I do to improve the health of my garden and neighborhood?”  Plant flowering herbs and perennials to provide habitat for all the good guys.  This invites not only the incredibly important honeybees (required to produce 35% of the world’s agriculture!), but all of the other amazing pollinators as well, such as hummingbird moths, swallowtail butterflies, skippers, and hummingbirds themselves.  The seeds from unharvested flowers will go on to feed birds like my favorite feathered friend, the goldfinch.  You’ll also be creating space for other types of beneficial insects that feed on any pests and in no time, you’ll have a thriving and humming ecosystem in your yard.  Beautiful, calming, helpful, and beneficial for all.  A great way to give back.


For heaven’s sake, don’t forget to plant native milkweed for monarchs!  I’ll talk more about this brilliant creature next week, but for now, we’re giving away a free pack if you buy 5 packs or more of any seeds from us. You can shop our seeds here. You can also get a free pack of seeds here!


  It’s important to try to avoid using synthetic chemicals in the garden.  Try insecticidal soap or neem instead of Sevin.  Try mulch instead of Roundup.  It’s a little more work, but it’s so much better for so many reasons.  I know the manufacturer tries to say Roundup is biodegradable, but the truth is that it is found in not only soil, creeks, rivers and lakes, but also in rainwater and the urine of 80% all people in the U.S.  That’s not biodegradable.  That’s frightening.  

  It all ripples outward.  Everything we do has effects beyond what we see.  So continue to plant seeds of goodwill in your garden and your heart and you are doing your part to create a more harmonious world.  There’s 8 billion of us.  If we all plant just one seed each, that’s still 8 billion seeds.  You matter.  Your contributions matter, so never think that it's not worth it to do even one little thing.  It does matter.

   Have a great weekend and take a minute to enjoy a flower, a bee, a leaf, or whatever else may flutter by.