Ken Allan sweet potato flower Vegetable Garden


Living with Potato Bugs

For the most part, I ignore the bugs in my garden and they ignore me. This may be due, at least in part, to the hay mulch in my garden which is host to a lot of spiders. I don't know what the spiders eat but it is not the hay (or my crop plants) so they are probably allowing me to live in blissful ignorance of a host of potential problems. The two pests which I have found I cannot ignore are cabbage worms and potato bugs.

My solution with cabbage worms was simple. I stopped growing brassicas. This was an easy decision — I like cabbage, cauliflower, broccoli and Brussels sprouts but I don't love them. Plus, the flavour of commercially grown brassicas is equal to the best I can do. And they are cheap. And when a commercial brassica is served for supper, I never find a cooked cabbage worm at the base of a cauliflower floret (or worse yet — half a worm).

Potatoes are another matter. For such a bland root crop, the flavour of new potatoes is surprisingly distinct and delicious. And new potatoes are best the day they are dug — a considerable incentive for this home gardener to grow his own.

Which brings me back to potato bugs (Colorado potato beetles).

Left to their own devices, potato bugs will multiply until they are sufficient to strip a row (or a field) of potato plants. I used to control them with rotenone which has the organic seal of approval for use in emergency situations because it degrades quickly and because it is not harmful to warm blooded animals. Then one summer, about 20 years ago, I had just finished dusting the potatoes with rotenone, a white powder, when a perky bird (with a big beak and an orange breast) swooped down and ate a white potato bug. My heart sank. Rotenone is not supposed to be poisonous to birds but I can't imagine it is good for them. That was the last time I used rotenone in my garden.

I'm not a bird person but I did a little research and discovered that my bird was a Rose Breasted Grosbeak. Furthermore, in the 1800s, it was also called The Potato Bug Bird. Over the next few years, I observed that the main attraction in my garden for these birds was my late tall Spanish Skyscraper peas. In fact, the birds didn't show up until the peas were ripe.

The lateness of their arrival left time for the potato bugs to multiply and I soon realised that even though the birds were snacking in my potato rows, they were mainly eating my peas and were not making much of an impact on the bugs. I had hoped the birds were going to be the answer to my potato bug problem and wasn't quite ready to give up on that possibility. I was willing to plant an extra row of peas for the birds if they would work with me on the bug problem.

In the meantime, I sprayed with Bt (Bacillus thuringiensis). This is not as lethal as rotenone but it seems to put the bugs off their food, reducing damage and multiplication. Since then a strain of Bt has been introduced which is more effective for potato bugs.

My next step was to delay planting my potatoes by about one month. My idea was to have the bugs and birds arrive at the same time so the birds would have a better shot at keeping them in check.

Potatoes like moderate temperatures and this delay in planting meant they were doing most of their growing during the hot part of our summer. This was not good for production but that was not a problem for me. I grow them for my own use (and mainly for new potatoes) so my crop does not have to be competitive with commercial crops. I was willing to grow a reduced crop if it meant I didn't have to fight the bugs.

As a partial solution to the potato bug problem, the planting delay was remarkably successful. Because of the delay, I missed the first flush of bugs and in some years they seemed to miss me entirely. And when they did find me, the birds usually kept them in check. But not always.

The final step in my procedure came with the brief (temporary) introduction of New Leaf potatoes.

In 1997, Becker's Seed Potatoes offered "New Leaf Russet Burbank — The old familiar Russet Burbank patented with a Bt enhanced gene giving it Colorado Potato Beetle resistance." Who could resist? Actually, I had no interest in growing this potato as a food crop but I had been reading some of the critical comments on this potato and decided I should have a first hand look.

New Leaf Russet Burbank was, in some ways, very impressive. It grew very strongly and, as advertised, shrugged off potato beetles. The tubers were large and there were lots of them. In 1977, this was the best yielding potato variety in my garden. There was just one odd thing about the tubers—they were very lumpy. Most potato varieties produce an occasional tuber with a dome-shaped lump like a small half tuber welded to the side of the main tuber. In the case of New Leaaf, there wasn’t a single large tuber that didn’t have one or more such protuberances.

They tasted okay. I cooked one of them just to see, and then set the rest aside.

I was still not interested in them as a crop plant but I decided to use a few of them the following year as potato bug traps. In 1998, I planted two or three New Leaf potatoes, evenly spaced, in each potato row to slow down potato bugs as they marched down my rows. This seemed to work reasonably well, though I almost lost track of some of the New Leaf plants because they were the weakest growers in each row. At harvest time, the tubers were smaller than any of my other varieties.

My theory (about the poor production in their second year) is that when the Monsanto genetic engineers were transplanting the Bt gene into Russet Burbank, they got a number of successful transplants, none of which were identical in all visible respects to the original Russet Burbank. They decided to run with this one, despite its harmless lumpiness, because it was so productive. If they tested for resistance to viruses, they decided to ignore its poor performance.

When I get a new virus free potato variety, the first year in my garden is always the best. As it picks up viruses in my soil, performance goes down from year to year until I finally have to get new virus free stock and start fresh again. I’m guessing that New Leaf Russet Burbank did so poorly in the second year because it has lower resistance to viruses than any variety I have ever grown.

In their 1999 catalogue, Becker’s reported “We regret to inform our customers that we have been notified that Newleaf varieties are no longer available for sale into the Home Garden market. This was a corporate decision based strictly on volume of sales, and their desire to focus on commercial growers.”

Since then, I have continued to save enough New Leaf tubers to plant one every 15 feet in a row of potatoes. This practice, in combination with late planting and my Rose Breasted Grosbeaks, means I no longer have to worry about potato bugs.

Note on GMOs

I am comfortable with a few GMO potatoes in my potato rows. But I would guess that if I tried to get my garden certified, organic authorities would not be so comfortable.

Despite feeling okay with my use of New Leaf, I am not the least bit comfortable with GMOs in general. While I think that GMOs are theoretically capable of doing a great deal of good, they are also capable of doing harm. Among the positive uses of GMOs, the one that rings loudest for me is the genetic modification of plants and animals to produce life saving drugs which are otherwise prohibitively expensive (of course these GMOs must be grown in such a way that they will never get into the general population). The most prevalent use, currently, of this technology is to produce crop plants which can be sprayed with herbicide without getting sick. I want no part of this application (either as grower or consumer).

I have many concerns with GMOs. One of them is with the uncontrolled release of new and unusual genetic material into the general population. When European species were introduced into Australia, New Zealand and America to solve specific problems there were almost always unexpected negative results. We can expect the release of "good" GMOs to have similarly unpredictable effects.

Another concern, a big one, is with accidental mutations which occur as part of the process when a gene is moved from one species to another. For example, my New Leaf potato displayed three changes (high yield, lumpy tubers, low virus resistance) unconnected with the Bt gene, the gene being transplanted. The fact that one of these changes was a positive one in no way mitigates my concern that the genetic engineers do not have good control over what happens when they transfer genes.

Proponents of gene splicing like to use the analogy of splicing a scene into a movie. In fact when they describe exactly how gene splicing is done it is quite impressive and ingenious, but it is apparent that there is much more floundering about than is implied in the movie analogy. Along with the desired DNA transplant there is usually extra foreign DNA introduced into the target plant; and, also, there may be some (perhaps numerous) disruptions in the genetic code of the target cells.

When gene transplants are done, the GMO technicians typically do a large number of gene transfers and then select the most successful. If an individual GMO is identified in which the transplant was successful but where there were other undesirable changes, that individual will be rejected (unless it was the best of the lot). But even if the technicians obtain successful GMOs with no apparent undesirable mutations, there are quite likely to be invisible genetic changes, the effects of which will only appear at a later date.

Everyone who eats genetically altered food or food from a genetically altered source is participating in a feeding trial. And this is likely to be a trial which has not been preceded by animal testing. Before a GMO is released it is subjected to a great deal of testing, but most of the testing is to see if they made the transfer they were trying to make. There is little to no testing for safety. In particular, animal feeding tests are not required.

Transgenic researchers are fighting an image created many years ago by Mary Shelley’s Frankenstein, an image kept fresh in this century by the movie industry. Perhaps it is because of this that there is a great deal of pressure on researchers to maintain a clean record. When Dr. Arpad Pusztai (working for the publicly funded Rowett Research Institute in Aberdeen, Scotland) reported that his rats were doing poorly (negative effects on brain, liver and immune system) on a diet of transgenic potatoes, he got fired.

It is not the potatoes which scare me the most in this instance. These potatoes were altered to produce specific lectins, storage proteins, which increase insect resistance. The potato's ability to produce this particular lectin came from genes transplanted from snowdrop and jackbean. Nobody knew how the lectin would affect the eating quality of these potatoes (the hope would be that the lectins would appear in the leaves but not the tubers as do the potato’s own poisonous alkaloids) so, presumably, they were going to be tested more thoroughly than if, for example, they had had their vitamin producing ability jacked up a few notches.

What scares me is that the institute was so disturbed at the release of negative results that they immediately got rid of Dr. Pusztai and tried to whitewash his report. His negative results were tentative and the institute denied him (or any other researcher) the opportunity to repeat his feeding test on a larger scale to confirm or deny his suspicions. They argued that the feeding test, which he did on his own initiative, was not required. If a public institution (with just a small percent of their funding coming from private sources) reacts this way, what chance do we have of getting the truth from private companies?

In additional to animal feeding trials, we need labelling. As things stand now, if a GMO food became suspect, how would it be proved to be a problem? If we had labelling, we would at least have a control group for statistical studies on suspect foods because there is certain to be a percentage of the population which will avoid transgenic food with religious fervour.


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