Colorado Potato Beetles

[Durgan]

Nothing growing in my garden now so am reviewing issues that may be of interest.

The potato plants are very small and while checking around them, some Colorado Potato Beetles were found as soon as the plants emerged. 16 May 2012. These bugs overwinter as adults and each bug lays about 50 eggs on one of its hosts, potato plants under usually the lower leaves. With a small patch of plants it is possible to pick them off and better still find the egg clusters before they hatch. Large patches must be sprayed. They cannot be ignored, since in a few days a potato patch vegetation will be completely destroyed. I have lived many places in Canada and have always had potato bugs in the garden. The beetle also attacks egg plant in my garden.


12 June 2012 Larvae of Colorado Potato Beetle
Since about the 18 of April, I have picked about 200 adults, 60 egg clusters, and probably around a 1000 larvae. I picked them off for about five weeks four times per day. There are only 70 plants.

A few facts about the Colorado Potato Beetle.
From egg to laying adult takes 22 days under ideal conditions.
One adult lays an egg cluster of about 60 eggs at one sitting. During their life span of generally about five weeks a female can lay about 300 eggs.
The second generation adults either lays eggs or go into dormant mode for next years assault.
They survive as adults in the soil during the dormant period.
The eggs turn into larvae (munchies my term), moult four times before turning into adults.
Apparently they become immune to pesticides rather quickly, so the same control should not be used year after year.
Egg plant is a host.
A hot three days and the hatching eggs can lay waste to a patch of potatoes, absolutely strip the leaves clean.
The infestations get more severe each year if no action is taken.
Crop rotation must be a field about half a mile distant.
The beetle did not originate in Colorado, but is of Mexican origin.

 

[digitS']

It is disappointing when plants are attacked by pests upon emergence. The consequences are rather dire.

Neither potatoes nor tomatoes are horribly at risk in my gardens. Rather, it was the eggplants that just couldn't be resisted by the pests! When the Bt spray specific for beetles was taken off the market, I should have known I was in trouble. Instead, I planted the most eggplants that I had ever attempted. Despite weekly spraying with pyrethrum, I couldn't keep them off for more than a few days. Some plants actually died but even those that were able to produce may as well have been pulled. The fruit was very bitter, probably because the plants were under so much stress. While the eggplants were going under, peppers in the next row were completely ignored. I never even saw a beetle on them.

Each year, where I first notice the beetles is on nightshade. This might be a good location for that weed. The plants will produce seed even if they only reach an inch or 2 in height. Any cultivated field around here has nightshade and the beetles start there. But, they must be able to smell an eggplant from a 100 yards away. Near the end of the season, the ground around the plants was littered with dead beetles from the pyrethrum spray!

It was a great relief to have given spinosad a try and learned that it is pretty darned effective against the beetles. Having so many eggplants in my garden basket was something of a nightmare that year!

Steve

 

[Durgan]

I only had four egg plants, thanks goodness, so could remove the Colorado Potato Beetles by hand. The sweet peppers next to the egg plants were not attacked. I am beginning to associate gardening with "the battle of the bugs".

 

[Smart Red]

Last year I found and removed 19 adult CPB's from my potato plants. Someone must have had a fun time before I spotted it, because a while later I saw many of those voracious red eating machines making a picnic of my potato patch. I let the chickens into the garden for one afternoon and viola! not one Colorado Potato Beetle juvenile to be found.

This year - could it have been the drought? - I didn't fined a single CPB.

In fact, as I've mentioned earlier, this was the Year That Had No. . . (Bugs being one of the thing that I didn't have!) At least in my gardens.

Love, Smart Red