The Butchart Chronicles : September 9, 2015

Assassins in the Dahlias!

If you’ve been along the Dahlia Walk you might notice some of the dahlias are taller than you and me! They wouldn’t get half that far without help from three different types of ‘assassins’ – predatory insects for IPM (Integrated Pest Management) is what we are talking about here, not the latest production out of Hollywood. We were out in the garden in early July with IPM Coordinator, Tracy Ferreira, when the dahlias were but knee high. She gave us the low-down on our biological approach to pest management with respect to the border.

Integrated pest management at The Gardens involves the use of cultural, mechanical, biological and chemical controls to manage pest problems preventatively. In July, Tracy was applying three types of biological IPM:

Field Mite Preventor – Amblyseius fallacis

Field mite preventor

This biological control comes on bush bean leaf pieces. As you can see below, our IPM Coordinator is actually applying these leaves which contain the A. fallacis to each individual dahlia plant.

Tracy Ferreira in the dahlia border applying IMP

(Note the spacing of the dahlias? This is an example of cultural IPM, allowing for proper plant growth and air flow.)

Aphid Eliminator – Aphidoletes aphidimyza

Field mite preventor
Aphids are nasty business for the home gardener as well as commercial gardeners. We use a variety of biological controls, this is one example. A. aphidimyza is released and it flies amongst the plants searching for aphids. Females can deposit between 100-250 small, shiny orange eggs singly or in small groups among aphid colonies. They hatch in 2-3 days. They love 68−80 °F / 20-27 °C and high relative humidity – perfect for release in July!

A. aphidimyza

See above an adult A. aphidimyza that has emerged from the substrate just before release.

Thrips Eliminator – Neoseiulus cucumeris

Neoseiulus cucumeris - thrips eliminatorCucumeris love thrips, mostly the immature ones before they become a problem, which suits us fine. Cucumeris lay eggs too and they hatch into the small nymph forms which also devour thrips. (Fun fact:  the singular and plural form for ‘thrips’ are the same!)  Cucumeris is a very cost effective predator for us and while we have to release a lot, they eat a lot!







N. cucumeris comes in a bottle of bran – this is sprinkled liberally on each plant.

Neoseiulus cucumeris - thrips eliminator

Tracy applying N. cucumeris to the dahlias (early July 2015)

Tracy Ferreira in the dahlia border applying IMP

See the white border of alyssum along the edge of the dahlia border? While pretty and accentuating, those are not the only reason for it being there. In fact, it is a major source of food for our predators at certain life stages! Much here has a multi-faceted purpose – the goal being to bring you the absolute best possible visitor experience in Jennie’s beloved gardens.

And now for the results - take a look at the Dahlia Walk just off the Concert Lawn a few days ago...

Dahlia Walk 2015 at The Butchart Gardens
Dahlia Walk 2015 at The Butchart Gardens

Addendum:  Watch King 5 News' video on IPM at The Gardens:  Bugs deployed as pest assassins at Butchart Gardens