Colorado Potato Beetle (CPB)

This was my first year to experience the Colorado Potato Beetle in my potato patch. I have eight 60 ft rows of Reds, Russetts and Yucon Gold potatoes and I have removed more than a hundred adult beetles from my plants. A neighbor completely lost his potato crop the previous year and the garden next to mine was infested with the juvinile beetles as well. My crop this year was the earlist to go in and the plants were about a foot tall or more before I began seeing the adult beetles. I have been hand picking the beetles from the tops of the plants on warm sunny days or whenever I spot them on the ground. The yellow gold egg clusters of up to 30 or so eggs have all been located on the south facing, lower leaves, at just about ground level. I smashed these with my fingers and so far I have found about two or three times as many egg clusters as beetles.

I have made some other interesting observations and have been researching these CPB's on the net as well. Thought I would post something here at DG to see if there was any interest in the subject in the Rocky Mountain forum since this seems to be a favorite haunting place for this little varmet...I do not use pesticides and from what I have read so far the CPB's are resistant to most registered chemicals. The hand picking seems to have things under control for now, but I would like to see if this sujbect carries any interest in the RM forum.

morgan

I would be inclined to try an organic treatment like Neem oil, mraider3. Keeping up with an infestation by hand is difficult. Haven't had to deal with the CPB myself. This does look to be a big year for grasshoppers (aka Trout bait) and I have squash bugs that I don't want to get out of hand.

The San Diego strain of Bt is supposed to be for Colorado Potato Beetles. I haven't used it, but I've never had 80 feet of potatos, either. On my little potato patch, finding and squishing the eggs was no big deal.

I have read some of the pros and cons on chemical (organic) and biolotical (Bt) and although effective on large scale operations I don't think they would do much better than the hand picking procedure I have been using. Problem is the majority of home gardners don't have the luxury of time to constantly monitor their potoato crop. I walk the isles constantly while doing watering. weeding, etc. and have had little problem so far with instars until yesterday when the the third stage beetles, which looks a lot like a lady bug, began to emerge. I caught three as well as half a dozen adults. The instar stages are considered the most destructive, however I have seen little damage to foliage on my crop to date. Neighbor's crop however is not doning as well. His is crop is much smaller than mine in size and numbers, and doesn't get the attention mine does. I picked 16 adults off his plants several days ago and only four off mine. A word of caution when picking the beetles by hand. If you have sensitive skin you might want to wear gloves when picking the adults off the tops of the plants. I have two areas where I thought I had come into contact with poison ivy somewhere which I am extremely alergic too. I read that the beetles can give off a toxin which can irritate the skin and you should not touch your face or eyes when picking by hand. I treated these areas like poison ivy and this seems to work, but very itchy. I scratched one before I knew I had the problem and it spread over my arm just like poison ivy.

Well daylights come and de wanna go work in de garden!

dparsons, what are you doing with your squash bugs? Mine have struck early this year, and so far I've been hand-picking them off and scraping off any egg clusters I find, but as the plants get larger it's going to be really hard to check every leaf.

They've just started appearing and I haven't gone after them this year yet. Previously I sprayed the plants/leaves with Neem oil and it kept them back. I did it twice early in the season and didn't have problems late in the season, so I didn't need to re-apply after that. I also squished eggs on occasion. I have a supply of Bt, but don't know how effective it is against squash bugs. It is effective against various worms that show up on tomatos. I'm one of those people who doesn't have enough time to hand-pick the bugs off on a daily basis, so an alternate organic means is helpful.

Yeah, I'm running out of time because the leaves are getting too big and too numerous. I've tried sprinkling the leaves with garlic powder and that did seem to help a bit. I'll try Neem oil; I think I've got some here someplace.

I don't think the Bt for Potato beetles will work on Squash bugs, and the Bt for Caterpillars definately won't work on Squash bugs.

Dave, I just got some neem oil and sprayed it on my squash plants in hopes that it would take care of the squash bugs, but what about bees? Did you find that it had a negative effect on them? I was watching them entering the squash flowers this morning and feeling really guilty!

Well, what does the label say about bees?
If the blossoms were new, and weren't open when you sprayed, maybe the bees didn't have much exposure.

The label, she say nothing (kinda like the Tar Baby...) It doesn't even say how to use it; I copied some instructions from DG.

I'm just hoping I haven't killed any bees. Some of the blossoms were open, and I didn't spray into them, but in order to get the undersides of the leaves I had to do a bit of generalized spraying.

I didn't notice any effect on the bees. I didn't spray the flowers and, like pollengarden said, new flowers open and you haven't sprayed inside.

That's reassuring, DWID! I haven't checked except in a very cursory fashion since I sprayed. Do I have to spray again after we water with the overhead oscillator? And what recipe did you use for your neem oil spray?

Neem Oil...Read that this product when used in garden will also harm ladybugs and other helpful insects. Was tempted to use it on indoor pepper seedlings, however the problem didn't occur this year for some reason. The latest update on the CPB's are a recent hatch of the larvae or instars which has been doing a number on the foliage of some of the plants. They seem to be 'localized', that is they don't wander too far from the plant where the eggs hatched, but they double in size daily and if left unsquashed they will quickly defoliate a plant. I have been using latex gloves to squash the buggers, some which are already the size of the adult beetle. The larvae transform into a beetle before pupating in the ground. This beetle doesn't look anything like the adults which confused me last year when I saw them on the neighbors potato plants. So far I am staying ahead of the game and the potato plants are starting to flower, so any leaf damage should be minimal to production.

One thing I find interesting is the number of parasitic insects which are on my potato plants which includes not only ladybugs, but some stink bugs, several kinds of small parasitic wasps, some small black flies, and some large yellow and black wasps. With the exception of the yellow and black wasps all of these insects were said to feed on the instars so one more reason not to spray. Obviously the parasitic insects probably only take care of a fraction of the instars, but from what I have read the CPB is extremely resistant to pestices, and I can only conclude from that, they are probably fairly resistent to neem oil products as well.

The biggest problem to hand picking or smashing this year is the amount of rain we have been getting. Access to the garden may be restricted for a day or two at a time, which allows these instars to feast at will. Like their adult counter part though they will move to the tops of the plants in a couple of days if unchecked and are easier to spot and smash.

An article on Wikipedia says its not known to be harmful to ladybugs or honeybees. "Not known to be" isn't the same as "known not to be" though. It also says Neem oil works as a repellent and is a larvacide.

http://en.wikipedia.org/wiki/Neem_oil

It is my understanding that Neem oil has a more lethal effect on bugs that try to eat the plant with it on than on those that walk across it, and is likely more lethal when wet and sprayed on a bug than when dry.

Greenhouse_gal, the recipe I use is just what is printed on the bottle. I don't know the brand off-hand. It comes concentrated so it gets mixed with water. The product has a surfactant in it so that the Neem oil will mix with water. As for re-application after watering/rain, I would check and see if the bugs come back. I haven't had to make multiple applications after every rain previously.

Another link.

http://www.wisegeek.com/what-is-neem-oil.htm

I found one egg cluster today when I went looking, but the eggs were darker than usual. I don't know if that means they were about to hatch or if they weren't viable because of the neem. My neem oil container doesn't have any instructions; it's Dyna-Gro Pure Neem Oil, so that's why I asked. Mine has no surfactant in it, so I added a little soap along with the water. What brand do you use?

I have "Green Light" brand Neem Oil. Its has a 70% Neem oil concentration. The label says to use 2 tablespoons per gallon.

Thanks, Dave! Sounds like it works, too. Nice to know there are other alternatives. It must be really powerful stuff, huh?

I think it is pretty powerful.

It still amazes me that there are things that are selectively toxic.

I've seen one or two juveniles and one adult since I sprayed, and my plants are looking good. I admit that I haven't really searched for the beasts, but the neem really did seem to make a huge difference. I'm sure it helped that I was policing them so carefully earlier, and destroying eggs. I did notice one egg cluster today which I scraped off, but it was a darker red than usual and didn't look as healthy.

I get this image of you out patrolling your garden, dressed in your khakis and armed with a spray bottle. :)

Nope, wrong image. Dressed in jean shorts and armed with nothing more than fairly sharp fingernails. And a deathwish for all squash bugs...

Started digging potatoes last week and the results were fantastic. A local nursery has been advertising a biological powder for the CPB which I understand has to be applied directly to the beetle or larvae to be effective. Frankly I can't see how this would work with hatches going on all the time. I am still smashing upwards of a hundred larvae per day, but I am winning the battle. None of the larvae (instar) have reached the beetle stage or fourth stage that I am aware of. Damage to the 500 ft of potato plants is minimal compared to local reports from other gardners. I admit to spending an hour or more each day smashing larvae but I appear to have won the battle. By my calculation I have probably killed more than 400 adult beetles (first round) and 10,000 larvae. I rarely see any adult beetles which could have produced 1,000,000 offspring in the second generation if the larvae had gone unchecked.

Congratulations! Sounds like you're winning the fight, but what dedication to the cause!

greenhouse_gal...precisely my words. I now only check about every other day and work on smashing the larger instars (about the size of the tip of my little finger) which blatantly march to the top of the potato plants an sit there in plain site daring me to pick them off their roost. Fortunately I have not seen a single instar beetle so as you say dedication has paid off. Any damage they do now is irrelevant since the potatoes are well developed, but I still wonder what next year will bring with all the troubles we have had here in the valley with these critters.

Along the same lines the pine beetles which have been devastating our pine trees will be a hundred times worse next year as reported because nothing was done to control them this year. The attitude here is the problem will correct itself when the forest is gone. On the other side of McDonald Pass they have taken preventative measures to remove the dead wood and have made some success in saving a percentage of their forest area. It sort of reminds me of the Yellowstone fire a few years back when the headman decided to let the fire burn itself out instead of taking action. He got fired!

Back in the 60's when I was in college I worked for the parks department in Wichita. The director, a Brown University graduate was faced with a similar problem caused by the Dutch Elm Beetle. They were sweeping across the country killing American Elm trees. As they spread westward they left complete distruction of the hundred or more year old Am. Elms in their path. The core area of town was mostly Am. Elms, more than 60 feet tall and six feet in circumference. John's approach to the problem was to cut down any tree in the parking areas which showed signs of beetle infestation. Flagging (yellowing of some of the leaves) was the indicator and the city forestry crews would show up and remove everything except the stump. People in town were in an uproar when these crews would show up and began cutting. But John stuck by his guns and saved 40 percent of the old American Elms which was a feat no one else had accomplished.

I have noticed a huge increase in grasshoppers this year in my garden. Although they don't appear to have made any significant damage to any of the crops, I have seen numerouse holes in most of the plants. They do not seem host particular and I wonder what would happen if they increased more than a hundred fold next season. I have heard that this may be a more serioius problem across the country in another year or so. Scarry thought!

Mraider, I was concerned about CPBs as well, so I put my potatoes in a half wine barrel on top of the concrete blocks that make up our compost pile, next to the chicken yard and far away from the rest of the garden. The last time I planted potatoes it was as if I had rung a dinner bell for the CPBs; they showed up in hordes and they were a pest in my garden for years afterwards. This time I saw nary a beetle, and I'm thinking that the elevated position might have saved them. Also, if I found any, I planned to feed them to the chickens instantly.

That was very wise of John to take such drastic action. It's amazing that he was able to save some American Elms that way. It's probably one of the few places where they still exist!

greenhouse_gal...I am curious too about next years crop of potato beetles. I am going to burn the stems and leaves rather than compost them in the back of my yard as before and I am cutting down to four rows instead of eight. I rotate on a five year plan, but that is probably of little value with the range of these buggers. I read that they migrated from Mexico through the Rockies and eastward at over 80 miles per year. Infestations throughout the valley here will undoubtly be of concern in areas nearby where they raise seed potatoes for Idaho. Last year an early freeze got most of the seed potatoes and I would wager the beetles have had a hayday with their crops just as mine. Potatoes have been a cheep source of food but that could change quickly if the pesticides used don't take care of the problem. As adaptable as these critters are I would not want to buy potatoes from the grocery stores with the amount of pesticides required to control them.

I think burning the stems and leaves is a good idea. It's so tempting to compost all that lush vegetation, but we have never been able to get our compost to cook well enough to destroy larvae or other problems like diseases. I didn't realize that there were still any areas without CPBs, though. Don't most potato farms use a lot of pesticides anyway? That's why I buy organic potatoes!

I have read that potatoes are top of the list for pesticides. Since these beetles are extremely adaptive to pesticides, twhat is available to the gardner is generally not effective enough to eliminate the problem. I am still finding a few of the instars in my patch, however no second generation bettles have appeared. The effort to eliminate these pests has been exhaustingly difficult and my neighbors think I'm nuts. Welcome to morgan's crazy farm!

I thought that potatoes tend to be high in pesticides because pesticides tend to accumulate in the soil. I assume that you should either buy/grow organic, or wash AND peel.

I figured that they were high in pesticides because they were prey to so many critters. Most assessments of pesticide loading assume that you will wash and/or peel the product before eating anyway, so what they find when they test is what's left after that's been done. I am not sure washing and peeling does very much, although I'm sure it helps. The problem is that there is a systemic load so that the chemical is taken up and is all through the plant and fruit.

Organic potatoes are available here - just not in much variety.

greenhouse_gal....still trying to get my head around the idea of washing/peeling potatoes to remove pesticides. If the pesticides are accumulative in the soil and I'm assuming most commercial potato farms don't rotate crops, does this really remove the pesticides from the meat of the patoato???

Only if you want to sell pesticide-laden potatos without hearing complaints, mraider3.

mraider, that's my point. There's got to be some systemic uptake of the pesticides into the interior of the potato. That's why foliar spraying of fertilizers and seaweed extracts work. Same thing for peaches and apples and all the other things which get treated.

There are several things I have been reading about potatoes and pesticides which has me convincence that this may be one of the most dangerous crops on the market: (1) Potoatoes now lead the list of pesticide laden food crops in this country; (2) the CPB's are on the uprise which I can attest to in my garden for the very first time; (3) CPB's are extremely adaptive to pesticides; and (4) cancer is on the rise in twenty year old males (maybe a connection, maybe not). This may sound like some wild conspiracy theory, but I have completely given up eating out in resturants and purchasing any vegetables which are not labeled 'organic', which again is very seldom. It is also said that cheap food is what keeps people from going to war, but at what price. Off soapbox...let's just grow more pest free/pesticide free potaotes!