Mary's Veggie Garden

June 1, 2011

What’s Bugging My Garden? Colorado Potato Beetles and Beet Leafminers

Filed under: Beet Leafminer,Beets,Colorado Potato Beetle,Gardening,Insects,Pests,Potatoes,Vegetables — marysveggiegarden @ 11:34 am

Colorado Potato Beetle

Colorado Potato Beetle eggs on the back side of a potato leaf. The eggs are always on the back of the leaves.

May 25 I found a Colorado Potato beetle on a potato plant at my Vassar Farm plot. A quick inspection of the underside of the leaves revealed a cluster of bright orange-yellow eggs. May 31 I found 3 adult beetles in the potato patch and my inspection turned up 6 – 8 clusters of eggs. The adults move slowly and are easy to catch and crush against a rock. The eggs are soft and easy to crush against the leaf, though you might want to wear disposable gloves for the job.

Colorado Potato Beetle larvae are dome-shaped like the adults

Each egg cluster contains numerous eggs – I counted around 25 eggs in the photo. If you don’t find all the clusters, there will be lots of larvae, and they mess up the plants quickly.

It looks like this will be a bad year for Colorado Potato beetles. I don’t recall seeing a single adult last year and I found very few eggs. This year the beetles are out early and in force.

Beet Leafminer - the circled bump is the miner inside the leaf.

In early May Beet Leafminers attacked my beet greens. The tiny white eggs are laid in 2-4 egg clusters on the back of the leaves and are very difficult to see. After hatching the larva chews into the leaf and then lives and feeds between the top and bottom surfaces of the leaf. Often the first sign of an infestation is the dead area of the leaf where the larva tunneled. The most recent damage looks watery instead of dry, and the larva will be at the end of the watery area. Pinch the larva between thumb & index finger to prevent further damage. It is not necessary to remove the leaf.

If you cannot find the larva, it has probably left the leaf, to hide in the soil while it pupates into its adult form, a small fly.


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