Category Archives: Plants

Secusio extensa – fireweed biocontrol moth

A Secusio extensa moth on a yarrow plant.A Secusio extensa moth on a yarrow plant.
While out on a walk, I came across a patch of yarrow (Achillea millefolium) and thought the patterns made by the flowers would make a good photo. So I chose an individual plant to focus on and by good fortune found this moth hanging off the side.

The moth is Secusio extensa (I’ve also seen it referred to as Galtara extensa) and it hails from Madagascar. While this begins to smack of another invasive species, in fact this moth was deliberately introduced to the Hawaii in 2012. The reason for that is that the moth’s larvae feed on fireweed (Senecio madagascariensis) and fireweed is a truly bad invasive species here. Besides spreading in a prolific manner, it’s poisonous to livestock.

What I particularly liked about this individual was that it appeared to be enraptured by the yarrow plant, bobbing its head up and down continuously. I also loved its comb-like antennae, which are more properly known as pectinate antennae.

Brugmansia

A brugmansia grows beside the Kohala DitchA brugmansia flower
I grew a brugmansia at my old garden in Washington State. During the course of a summer, it grew to two or three feet high and bloomed. As I expected, the first serious dip in temperature reduced it to a sorry wilted remnant.

Here on the Big Island, such temperature dips aren’t a worry, so a brugmansia will grow to a very large shrub and carry its blooms a good while. This splendid specimen is growing next to the Kohala Ditch in North Kohala. The ditch was used to bring water from the Kohala Mountains to the sugar plantations. These days the water is mostly used for agricultural irrigation.

For more information about the history of the Kohala Ditch, go to fluminkohala.com/the-kohala-ditch.

Reclaiming the lava

A shrub grows in a lava field
Lava flows make for a stark landscape, but I always find it fascinating to see how, even in such barren ground, nature regains a foothold. Here, a small shrub has taken hold in a crack in the lava. Just below and to the left of it, a fern grows under a ledge.

If there’s enough rainfall, as there is in this spot of the southeast coast of the Big Island, vegetation will begin to take hold in a fairly short while. That’s assuming that a new flow doesn’t happen along and put paid to the process.