Thursday, June 14, 2012

Potato Bug Ponderings

A few days ago I discovered  the potato patch has been invaded by potato bugs, more accurately called Colorado Potato Beetles. This is the pretty striped adult,  but what I first noticed were the larvae,
fleshy, humpbacked orange critters, devouring the leaves of the potato plants until they turn into lacy, poop-covered shreds. No time to waste in dealing with these pests.
I think most organic gardeners hand-pick and squish these bugs, but that seemed too disgusting to me.  Instead I got a bowl of  water with dish soap and a spoon to knock them off the leaves into the water. We used this technique a couple times last year and it worked well.

In addition to knocking the larvae and parent beetles off the plants,  I checked under all the leaves for clusters of eggs and squished them with the  back of the spoon.  I only found a few adults and not too many eggs, so maybe we are on top of the problem.

This was a tedious, time-consuming task, but not unpleasant since it wasn't too hot this morning. I noticed curious things about the  potato beetles and began to wonder about some things. (I bet gardening has been the impetus for much scientific experimenting throughout the ages.)
For instance, I am growing several different heritage potato varieties, some of which have darker leaves and stems.  Most of the potato bug larvae on the dark green plants were  brown rather than red.  I wonder if there are two subspecies of potato bugs, with dark ones preferring dark plants for camouflage, or, if eating the darker plants causes their color variation?
The potato bug infestation was concentrated in the plants in the middle of the plot.  Most of the edge potatoes had no  potato bug larvae or eggs at all. Is that a demonstration that diversity is  more resistant than monocultures?  Does the initial potato bug land in the center of the patch to lay eggs and  the population works its way out to the edges?

It was  difficult to  knock the baby potato bug larvae in the crevices of the plants with the spoon, so I  sometimes resorted to squishing them, turning my thumb and fingers a vivid rust color. Hmmm, could you use potato bug larvae as a dye colorant?

At first I  found the larvae to be  repugnant, but as I worked the patch I tried to view the babies as their mom,  might -- cute, lovable little larvae.  It worked, and I actually felt a bit sad drowning them in soapy water, but I also felt very protective of my precious potato plants. If I don't significantly reduce their numbers, they will destroy my crop.

It took several hours to work my small potato patch, and I am sure I will have to do it at least once more to catch the bugs that eluded me.   If I were being paid minimum wage to grow these potatoes, I wonder how much per potato the pest control would cost?


Marcia said...

I don't grow potatoes. Not enough room in my small plot and we don't eat that many. But I know there are bugs out there I need to look for. Thanks for the reminder.

Jocelyn said...

I always say I couldn't afford to pay me if I were paid, so it's a good thing I'm not. It might be the same for you. :)

Congrats on battling those little buggers.