Pests and Pest Control
(Just before we begin, a quick apology to those of you who have been waiting so patiently for replies to your letters, as well as those of you anxiously awaiting the concluding segment of "The Burrow Presents..." It appears I am once again in the middle of preparing for an exam, and also trying to get a major essay completed. On top of this....and I'm really not complaining...the amount of mail I am receiving is growing astronomically. I have decided to try and get this particular article out for two reasons: a) I need a break from the studies, and b) part of this article deals with a subject that must be nipped in the bud, before any major problem develops. The good news is that the rest of the article deals with things that are really no problem at all,...but I'm jumping ahead of myself, so...why don't we just get to it?)
Now I happen to have it on very good authority (Willy told me), the first question asked by Hannibal, Alexander the Great, Napoleon, Generals Custer and Patton, and even Rambo, before going off to wage battle was, "Who we fighting?!" That's also the question we have to ask ourselves before we take any action, or we may find later that action was not necessary, or even worse, that the action we took served only to create a larger problem. So before we think about killing anything, let's take a look at what a worm bin really is, and as such, what it can be expected to contain (in fact what it must contain if it is to function properly.)
No matter how we look at it, or what fancy terms we tend to use, a worm bin is nothing more than a self-contained, adapted for the indoors, miniature compost heap. The precise manner in which we use the worm bin may differ from the outdoor pile (but not really very much), and it may house a proportionately-larger worm population than its larger outdoor cousin, but in the end, the fact remains, it is simply (and wonderfully) a small compost heap which produces an extremely high-grade finished product (there really is a difference between compost and vermicompost.) Therefore, like every other compost heap, it must, by its very nature, be teeming with life. Of the individual animals which make up this plethora (great word!) of life, very few actually deserve to be called "pests", since they are a vital ingredient for the successful decomposition of the organic wastes which all of us, as vermiculturists, are trying to have converted. With this in mind, let's take a quick look at exactly what it is that is happening during the transformation of organic waste into "black (or brown) gold." Some of what I am about to describe will be missing in a worm-bin situation (due to the smaller amounts of material), but it will be helpful as an aid to understanding the overall process.
(Just before we get started, and all the letters from
Master Composters start pouring in, I thought I should remind everybody...
what a pleasant person I really am.)
So anyway, when a large amount of organic waste is brought together in a heap, the following things tend to occur (assuming a suitable temperature range, adequate moisture, and in certain cases, air.) The pile is invaded by bacteria which specialize in breaking down organic compounds. Among the first of these invaders are those which are commonly referred to as mesophilic decomposers. These critters (much too small to be seen with the unaided eye), thrive in temperatures ranging between 50 degrees and 113 degrees on the Farenheit scale. Having gotten word of the "block party in progress", these little critters (25,000 of them laid end-to-end should measure close to an inch) do pretty much the same thing that you or I would do in the presence of all our friends, and all that food,...they party hardy. In no time at all, things begin to heat up (literally.) What's really interesting though, is the result of this increase in temperature brought about by all the energy which is being expended.
If my understanding of this procedure is correct, the next step is the inevitable arrival of the party crashers, in the form of thermophilic microorganisms, which just happen to enjoy temperatures between 113 degrees and 170 degrees Farenheit, the very temperatures which are quickly eliminating the mesophilic bacteria, whose activity caused it in the first place. In the event that the food supply is running low (in the sense of fresh compost), not an immediate problem, the thermophilic organisms have plenty of mesophilic corpses to clean up (nice guys, huh?) And now things really get interesting!
You see, while all this frenetic (another great word) energy is being expended (bringing the temperature in the pile up to its peak of 170-180 degrees Farenheit), a new group of critters has been quietly massing their troops at the borders to the frontier (the compost heap), unable to effectively join the party due to the rather uncomfortable temperatures. As the thermophilic microorganisms deplete their food supply, however, the overall activity diminishes, and the temperatures start to drop (a process referred to as stabilization.) As the temperature continues to do so, and the party crashers begin to crash (again having been the cause of their own demise), this new batch of troops, comprised mainly of actinomycetes and fungi decide to make their move, and take over the pile which is once again nice and cool (at this point, a fresh supply of organic waste could be used to start the entire cycle all over again.) Also at this point, so many different actors take the stage, that I think I had better switch to a slightly different approach, such as referring you all to the wonderful (I sincerely mean that as a compliment) Master Composter Programs that are becoming more popular, and thus more available every day. In all seriousness though (I will try to finish what I've started), these programs are well worth taking for anyone who is serious about their gardening and/or environmental concerns. An article of this nature, is simply no substitute for what these people can teach the rest of us.
The New Approach
These critters are basically a higher form of bacteria, which have several very notable characteristics. Just for starters, close your eyes for a moment, and imagine the beautiful smell so commonly associated with fresh soil. That's actinomycetes you're smelling. Now think of all the wonderful benefits you have heard of being derived from humus (if you haven't heard these things anywhere else, you certainly will when I manage to get my articles on "The Benefits to Plants Derived From Vermicompost" up onto these pages.) The actinomycetes are crucial to the formation of humus. Often working very deep in the soil, these ambitious bacteria convert dead organics into a type of peat, and also release various nutrients such as nitrogen and carbon, making it available for mixture into the top-soil. Since actinomycetes possess the ability to produce antibiotics, many other bacterial populations decrease as the number of actinomycetes increases.
When you speak of small animals (as opposed to bacteria) protozoa are about as small as you get. Other than that, there's not really much to add, except that they are present to a certain extent in compost, and are probably closer to bacteria in their actions than they are to the other animals.
Fungi are very simple (primitive) plants which are incapable of producing their own carbohydrates, since they lack the chlorophyll present in higher-level plant-forms. The family of fungi includes yeasts, molds, mushrooms, etc., and they survive on energy which they obtain from the organic matter in dead plants and animals. The presence of mushrooms in your compost heap or worm bin (very common with cardboard bedding) is a good indicator that the temperature of the bedding is around 70-75 degrees Farenheit (a great temperature for red worms), since only a few fungi the higher thermophilic temperatures (around 120 defrees Farenheit.)
NOTE:With the exception of some of the larger fungi, all of these things we have discussed so far have at least three things in common.
Another thing the above-mentioned organisms have in common is that they are basically what is referred to as level-one (or first-level) consumers (or decomposers.) This simply means that as their numbers increase in the pile, other larger decomposers will come along and invite the first-level decomposers out to dinner (as the main course...of course.) In this manner, population levels are kept in check, and the same thing happens to the second-level consumers in their turn. Since the higher-level decomposers are usually more suited to moderate temperatures, they will only be residents of the pile at certain times. It is mainly the second and third-level decomposers which are most often mistaken as pests (I'll bet you thought I was never going to get around to that), but the true fact of the matter is that they are among the most beneficial of the critters in both the heap and the bin.
Members of the same family as the spider and the tick (8 legs in common), this little creature is inevitably found in any compost situation, and if you think your bin is free of them, maybe take another look. Those most commonly found in a worm bin will be a reddish-brown in color, and very numerous. Moving around the surface of the bedding material, they attack dead plant matter, fly larvae, springtails, and even other mites. Several of the more popular books on vermicomposting describe these animals as hunting down red worms, paralyzing them in some manner, and effectively reducing the worm population. Others talk about them stealing worm cocoons and drinking the fluid from them, also reducing the worm population. The most common fear I have run into among novice worm-breeders regarding the mite, is the fear of damage to their houseplants. For my part, I can tell you that the only time I have seen a worm and a mite share dinner, the worm was in fact the only menu item, but I have never deduced anything significant from it except that the mites (there were several at work) were cleaning up the carcass of a recently deceased worm. (You very seldom find dead worms in a bin simply because the other decomposers tend to clean them up very fast.) As far as actually chasing the little wiggler down and thus creating his own dinner, I have never seen anything even suggestive of that type of behavior. Nor have I ever seen even one mite in the process of making egg-nog, scrambled eggs, or even eggs benedict. As for the plants, the mite which is to be feared in that regard is the red spider-mite, obviously some cousin of this mite, since I have planted numerous plants of various types directly in active worm bins which were saturated with these little animals, and never has even one taken up residence among the living portion of the plant. Aside from the fact that they are a little unsightly, they have never caused real grief in any worm bin in my care (and as I said, this is not due to lack of numbers, they obviously breed at least as well as the worms.)
Not to be confused with centipedes (a whole different story), the millipede can be distinguished by the two (2) pairs of legs attached to each body segment with the exception of the sections nearest the front (a centipede has only one set of legs per segment.) Vegetarians by nature, millipedes break down the larger pieces of plant matter, resulting in finer pieces being made available to the other decomposers which lack teeth, such as (you guessed it) Willy!
Now here is a third-level consumer (it feeds only on living animals such as insects, spiders, and worms), which must be hunted out in turn by something slightly larger, about the size of an average worm-breeder. Though more commonly found in an outdoor situation, just one of these things, in the confined space of a small worm bin, can do a lot of damage. On the upside, they're rather territorial (as are most predators....ask Arnie), so if you find one in a small bin, chances are you've eliminated the problem. The first real pest we've talked about.
This is one of those compost critters with a face only its mother could love. Even though it is strictly a vegetarian, and most common in an outdoor pile, that is probably where you would most like it to stay. Its fat little form would probably clash with the furniture anyway, and a good scream or two from your spouse should be enough to remind you that the best prevention for most of these particular animals is to simply never bring outdoor compost into the house without first cleaning it. (A good dose of solarization works wonders!)
Snails and Slugs
Another true pest as I'm sure any of you who garden have known for a long time. I'm just as sure that nature had a real good reason for these particular animals, but how she expected us to accept the fact that its favorite food is living plant material (such as that found in the garden you just wrecked your best jeans to get planted) is beyond me. The usual beer-traps (the non-alcoholic beer actually works better than the "real thing") is fine for outdoors, and if you have them in your indoor bin, try lightening up on your watering schedual. These animals like moisture.
The big brother to that little mite we were discussing a little earlier, and one of the least appreciated animals in the garden. Rather than being a pest, this animal is a great form of natural pest control. Every garden should have plenty, and if the one in the house is particularly bothersome, try looking it right in the eye, speaking to it in a very calm voice, then give it a wink...and step on it!
This is another of those little critters that I can almost guarantee will be present in virtually every vermicomposting situation sooner or later. Very small animals, usually no more than 1/4 inch in length, springtails will range in color from white to light grey, and even a sort of metallic blue from time to time. Feeding on decomposing plant matter, fungi, and pollens, as well as grains, they are most easily identified by their habit of "jumping" to a new location when they are disturbed. Since they accomplish this "jumping" by utilization of a specially-adapted tail-piece, their name becomes rather self-explanatory. Since they will die if they leave the environment of the worm bin, and since they are performing relatively the same job as the worms, I have never really considered them to be a problem. If you simply can't sleep at night (due to all that jumping around), then you may want to try method number one in the realm of "pest control." (The method I'm referring to will be explained a little further on, along with a couple of other "pest management strategies.")
The largest number of these compost invaders will be made up of the rove beetle, and the ground beetle. Both of these guys are third-level consumers, preying mainly on insects, snails, and even slugs. As a matter of fact, the black rove beetle is so efficient at this particular task, many people deliberately import them into gardens where slugs and snails have become a problem. Both of these beetles, as well as their larvae, will also feed on decaying vegetables.
Now these guys are certainly not welcome in most homes, and we will discuss steps to eliminate this problem in the section on pest control (method two). In the meantime, you may wish to know that an ant's idea of a smorgasbord would include any, or all of the following: any fruit, fungi, seeds, anything that is sweet, most other food scraps, other insects, and even other ants. (Get the picture? They like just about everything.) To make matters even worse, ants tend to think that compost piles, indoors or out, are really nifty places to build their nests. I once came across a nest over a foot around in one of my outdoor compost piles. It looked like some crazed drug dealer had decided to stash thousands of little white "pills" in the middle of my compost, and the only way I knew what I was looking at was by the frantic efforts of the ants to remove those "capsules" to a place of safety after I uncovered them. Unfortunately for the ants, the portion of the pile they had built their nest in was only two or three feet from the still-hot section of the pile, and by quickly transferring a couple shovelfuls of "eggs" into the center of the heated area, the invasion was very rapidly squelched. In a normal compost situation (outdoors, and without worms), I wouldn't worry about the ants, since by their very presence, they tend to mix the minerals around in such a way that they increase the phosphorus and potassium balance of the pile, but when the pile is home to a population of worms, the situation changes (the ants tend to deplete the carbohydrates which the worms require for food.) Thus, when it comes to a choice between the ants and the worms, those wonderful words of Arnie's quickly come to mind...."hasta la vista, babies" (or something like that.)
There are many types of flies, and many of them are true "pests." Some of them can also be very, very difficult to get rid of once they take up residence in or around the bin area. Most of those "strategies" which we will be getting to very soon now, relate to these airborne invaders, since they truly are the peskiest of the pests. Just before we get to that, however, there is one more type of "pest" to deal with, and I always find it strange that this is the "pest" I am most often asked about, and the one that people are most often bothered by.
Other Wormlike Critters
First of all, let me tell you straight out, the red worm population in your "worm" bin, is by no means the largest population the bin contains. Aside from the obvious winners in any contest which deals with population, the bacteria, there are also tremendous populations of "flatworms, rotifers, and nematodes, all of which are usually small enough that you don't have to bother looking them in the eye. There is also, however, at least (I stress at least) one other critter that is not only present in almost all compost situations, but usually in quantities vastly outnumbering the red worm population, and this little guy can easily be seen with the unaided eye. The animals I am referring to are the little tiny white worms, about a quarter of an inch long, that so many people mistake for red worm spawn. First of all, these are not red worms at all (red worm spawn are transparent at birth, with a visible red vein running the length of their body, and their normal red coloring is present within hours of the time they hatch), and these little white worms are also full grown. Commonly referred to as "pot worms" (since they're usually found in flower pots), I believe their proper name is "enchytraeid." Other than the fact that they're white in color, and very small, they are basically doing exactly the same thing as their red worm cousins, eating decayed organic matter. Since they are rather unsightly, however, it seems that most people would like to be rid of them, and though I am not of the same opinion, I will suggest a method (good old method one) that will help to at least keep their numbers down. In response to the various books which claim that these little guys could conceivably grow in such vast numbers that the resident red worm population might suffer from either lack of food, or lack of space, I can only say that I have never made it a point to deliberately try and keep the "pot worm" population in check, and I have never experienced any noticeable decline in the growth rate of my red worm population. At any rate, though this list of "compost critters is not exhaustive by any means, I think we've looked at the main occupants of both the indoor and outdoor-type compost piles, so let's take a quick look at how we can possibly deter a few of the peskier ones from choosing our specific location.
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Copyright © 1995, D. Brian Paley