by Leslie Cox; Friday, June 13, 2014

Nature has a way of balancing everything out…given enough time.

Of course, John and I have been practising due diligence in battling the forest caterpillar (Malacosoma disstria) outbreak we have again in our garden this year. (These guys have turquoise down their sides versus the orange on the tent caterpillars. They also do not build tents. Rather they lay mostly flat along a branch in a silken mat…which makes them much more difficult to spot unless you know what to look for.)

 

We paid particular attention as we were doing our late winter pruning…keeping a very sharp eye out for the tell-tale greyish bump of an over-wintering egg mass on a branch tip. They are surprisingly easy to spot…again, when you know what to look for and are concentrating in your search.

John pruned a few out of the birch tree where I killed masses of young larvae last spring. That was our biggest “hot spot” in our garden last year. He also cut out quite a number of egg masses from our variegated elderberry, Sambucus nigra ‘Marginata’. But at 25 ft (7.5 m) tall, I am afraid John was not able to reach them all.

I have been doing my bit too in pruning out the egg masses from my roses and any other shrub I happened to spot them on.

That was our first line of defence in getting this cyclical caterpillar pest under control.

The second line is an increase in the bird population in our garden. We always have a lot of birds in our garden every year but there seems to be even more this year.

Am also wondering if our resident garter snakes are helping out in snaring the caterpillars they encounter on the ground. Not outside the realm of possibility, I don’t think…especially since the snakes are looking particularly plump this year and I know they have not been eating my baby goldfish.

And for sure, both John and I are “dealing” with the furry caterpillars as encounter we them in the garden. Sometimes it is a good hunting day, others not so much.

But we saw something really interesting last weekend at Oyster Bay, just south of Campbell River, BC. We spotted a surprisingly large number of tents full of northern tent caterpillars (Malacosoma californicum pluviale) all along our walk of the grassy shoreline. All the caterpillars in the tents were dead. Just hanging by their hind legs, their bodies gently swaying in the breeze. I did not see one live one in any of the tents. Very strange.

Did see a few live ones outside of the tents, crawling around on the ground, on rocks, on branches.

Now I know there is a nuclear polyhedrus virus (NPV) that attacks and kills the caterpillars. But the caterpillars at Oyster Bay were not showing the usual symptoms of this viral infection…shrivelled bodies shaped in a “V”. These ones were not shrivelled at all.

Wondered if they had been sprayed with something but I am pretty sure Campbell River has a pesticide ban by-law in place…so the city should not have sprayed. Cannot imagine anyone else spraying them in a public place.

It is a mystery. But thankfully a good mystery as many of the bad guys are dead. Hopefully this means the population will be going down…way down…next year.

I would have loved to post photos of the tents laden with dead caterpillars…to cheer everyone up who is doing battle with these guys, but sadly, my camera was acting up. No usable photos.