The Milkweed Diaries

Monday, June 30, 2008

The Dreaded Spotted Cucumber Beetle

We are watching our squash and cucumber plants like hawks...looking out for the D.S.C.B.

They are not picky eaters at all--they will of course eat cucumbers, as their name suggests, but also squash and melons and even hawthorn leaves. I'm very protective of my Zephyr squash that's just starting to come in, so I've been vigilant about the beetles.

More than vigilant. More like a beetlecidal maniac. I prowl the rows, capturing and crushing. There are very few now, but I don't want them to make it to the point in their 6- to 9- week life cycle where they make more beetles. Only two showed themselves today, and both met quick deaths by squishing.

There seems to be some interesting research on drenching the soil with rhizobacteria, which simultaneously promotes plant growth and decreases the production of the phytochemical that encourages the beetles to feed. There are no innoculant blends yet, but it seems like such a great idea--stacking functions--to add beneficial bacteria to the soil and discourage beetles at the same time. There aren't any organic pesticides that are specific to the D.S.C.B. -- just broad spectrum pesticides that would kill beneficials too.

So for now it is prowl and squish. Wish me luck.


Jordana said...

How 'bout a predatory wasp? I seem to remember hearing about them for Mexican Bean Beetles.

Milkweed said...

YES. I've heard of the braconid wasp as a predator for the Spotted C.B. Attra says: "Natural predators of this pest include soldier beetles, tachinid flies (Celatoria diabroticae), braconid wasps, certain nematodes (38), and bats."

But though I've done lots of things to attract and protect beneficials, I've never actually brought in specific bugs -- it feels kind of intimidating!

Have you ever purchased beneficial insects, J-pants?

Jordana said...

I've not purchased them myself, but I remember Stan Cross from WWC getting some for the community garden they used to have there. I don't know if he still works there, but he was in the Environmental Leadership Center when I worked there. good luck!