By Julie Boudreau
The arctic willow hedge needs to be trimmed. But just before plunging the shears into the hedge, you discover a magnificent silver insect with its back marked by strange hieroglyphs: the calligrapha! Fascinated, or should I say, blinded by so much beauty, you completely forget the leaves he is chewing on.
Recognize a Calligrapher by His Handwriting
The Willow Calligrapha (Calligrapha multipunctata) is a beautiful round-shaped beetle, somewhat larger than a ladybug. It bears its name very well, because its abdomen (its back) has patterns that look like they have been drawn with ink. In Quebec, you”ll come across a dozen species of calligraphas, each with its own particular design. More or less thick lines, horseshoe shaped spots, scattered dots… The Willow Calligrapha is more specifically recognizable by the presence of a whitish band on its thorax (the part just behind the head).
It is in the middle of summer that this insect is most active. Being a close cousin of leaf beetles, calligrapher feeds on plant leaves. Luckily, it is not as voracious as leaf beetles and it is very rare that it manages to completely defoliate its victim.
What is generally scary with calligraphas is that there are a lot of them! Looks like an invasion. It’s a bit like morels: the first one is hard to see, but as soon as you see it… you see them all! On a shrubby willow plant, it’s possible to count hundreds of adults!
A Year in the Life of a Calligrapha
The calligrapha gives birth to a single generation of adults per year. Eggs are laid in early spring on host plants. Five days after being laid, the eggs hatch and the small white larvae begin to nibble the underside of the leaves. At this stage, the damage is so subtle that it is rarely noticed. After about twenty days, the larvae drop to the ground for the great metamorphosis. Then, another twenty days later, around mid-July, the adults emerge. This is when the nibbling of the leaves begins. Finally, in the fall, our well-fed friends drop to the ground and hide in the trash to let the winter pass.
The Willow, Its Main Victim
Calligraphers are quite specific when it comes to food. They usually stick to one species. Thus, the willow calligrapha feeds almost exclusively on willow. There is an elm calligrapha, who is interested in elms and an alder calligrapha whose preference is, yes, alders. There is also a tattooed dogwood calligrapha (C. rowena). Guess its host! The latter is sometimes confused with the willow calligrapha.
Do We Get Rid of It?
Given the not very voracious appetite of calligraphas, they rarely present a problem. The damage goes almost unnoticed. You can therefore conclude that it is an insect that can be tolerated. However, if the infestation were to take on extraordinary proportions, it is possible to control the populations by manually collecting the adults. For my part, the bowl of soapy water remains my intervention of choice. I wonder if the little hand held vacuum could work for calligraphas as it works wonders with Colorado potato beetles!
Finally, knowing that it spends the winter on the ground, near its food station, a good cleaning in the fall and a little mixing of the mulch (if there is mulch at the base of the shrubs) can complicate the adult overwintering.
Ultimately, the Calligrapha poses very little danger and deserves to be the target of our contemplation, because that’s about all there is to do with this garden insect. I even think that by connecting the dots of its calligraphic marking, you can read wow! on his back!