The Integration Part of IPM

The second is web-wiping. This works pretty well to reduce two-spotted mite numbers. It works like this: Certain spider mites, like the two-spotted mite, produce a fine webbing-which is especially abundant indoors. This webbing usually begins its life on the undersides of infested leaves. It is run from one side of the leaf, over the midrib, to the other side. This forms a tent of sorts. Inside this tent resides female mites, their eggs and offspring. The web tent affords protection from all sorts of hazards-like some sprays, predators, etc. Now here’s where the grower intervenes. With a soapy sponge, wipe the webbing away on leaves where it is practical to do so. Between leaves rinse the sponge in more soapy water to reduce the likelihood of transferring the problem to other plants. When you’re through, you’ve successfully taken a huge bite out of the overall mite population. Now all you should have to do is to mist the plants, not so much to remove any soapy residues but to actually increase the microclimate humidity surrounding the leaves. This slows the reestablishment of the pests- they like hot, dry conditions-and it creates a better atmosphere for most predatory mites (which should be introduced shortly after you’ve wiped out the webs). Again, I’ve gotten strange looks [or puzzled grunts over the phone] upon this suggestion-especially from commercial types-until it’s tried. Then they say “thanks.”

Physical controls does go way beyond handpicking, vacuuming and wiping webs. There are other forms which are more widely accepted. For instance let’s look at trapping. The scout’s tool for one thing, a.k.a. the sticky trap, catches pests. This is known. Now if you replicate the utilization of one trap a hundred fold, won’t the number of pests which are trapped be increased a hundred fold, too? I think that would be the case. (Warning: yellow sticky traps are dangerously non-selective and may trap many biocontrol agents.) There are many other types of traps. Not designed for scouting, but used exclusively to capture pests in order to reduce overall numbers. I can’t recommend all traps as being beneficial to pest control. Some, like I wrote about yellow sticky traps, are non-selective and can do more harm than good. Others tend to attract mating pairs to a crop location which can have negative consequences. The common Japanese beetle trap is one such trap. I heartily recommend against using this type of trap as it can lure many pests of both sexes but do not capture them all, as this can exacerbate the problem.

There are many other kinds of physical controls, though, which are worth their weight in gold. A pest barrier adhesive is one such type. This goop is applied in a band around the trunk of a host tree. As caterpillars, some ants and other pests try to cross this barrier they become hopelessly mired. This type of trap or barrier should be employed at a specific time of year depending on the life cycle of the target pest. An additional consideration regarding this type of control is that it is so effective, and so many pests are captured, a regular spot-check must be made to ensure the goop is not bridged by the dead pests trapped in it. If it is bridged, the remaining pests can navigate past the trap by walking on the bodies of their dead brethren. The goop must remain clean or be reapplied as deemed necessary. Other physical barriers can include diatomaceous earth and others, but I’ll wait before I get into the thick of it. Many of the finer points will be spelled out later on this website.

Plant health

There are characteristics concerning individual plants which may make some more susceptible to pests than others. These characteristics can include proximity — to vents, fans, sources of pests, etc. The attraction may also include the pests themselves, i.e., one pest leads to two pests which then leads to more. To clarify, pests send out allelochemic substances or chemical signals which to their fellow kind spell f-o-o-d, like a neon sign which says Eat at Joe’s. Or it’s like a group of people gawking at the scene of an automobile accident. To most people, curiosity make our necks a bit rubbery. Bugs are drawn to bugs as people are drawn to people. Another characteristic which may single out a specific plant amongst a crop of like plants is health. Like the lions to the antelope on the Serengeti, many pests will target the young, weak plant unable to defend itself. The plant which strays from the herd because it can’t keep pace. We see this plant as one with stunted growth or poor color. Perhaps it has a root malady or pest already. Regardless of the cause, the health, or lack thereof, is typically detected by pests long before we become aware of the condition. One reason for this is thought to be resonance. It is theorized that every living thing on earth emits a sort of energy-a vibration, if you will. All the healthy plants in the greenhouse or field resonate or vibrate on the same frequency. To the pests they see nothing which looks small enough to single out and take down. (Rarely will the lion enter the herd in an effort to take them all down.) They aren’t ambitious or stupid enough to think they have the ability to wipe out the entire crop (or herd as in the case of the lions). Pests do, however, have an uncanny ability to detect the weak plant-the one vibrating or resonating at a different frequency. The one standing out like a sore thumb. If your plants are healthy, the crop [herd] looks like one big indestructible entity moving in unison like a herd of antelope or school of bait fish. Is plant health important to pest control? I think it is. And, yes, Virginia, plants do have an immune system. So what’s the difference between an aphid and a lion? The number of fangs. And what’s the difference between a crop of plants and a herd of antelope? The plants can’t run like hell.

Trap- and banker-crops

Trap-crops first

Another way the antelope can keep from being eaten by lions is to hang out with pork chops. Okay, a silly analogy. But, nevertheless, it holds water in pest control. Let’s simply change the elements. Another way plants can avoid being attacked by pests is to hang out with crops those pests prefer. I’ve been curious about trap-crops for many years. I think a great deal of pest control merit goes to trap-crop logic. In order to prove it to myself, though, and because few growers were actually practicing this at the time, I set up a trial a number of years ago. This was the situation: My wife and I always grew bush beans in our garden. And every year those beans were attacked by Japanese beetles and Mexican bean beetles. We always harvested too many beans for our own immediate use but felt we could do better if not for these two pests. We did, after all, blanche and freeze our excess for off-season meals, so adding to our harvest wouldn’t be wasteful. One year we had some seeds left over from the previous season. I felt this was a perfect opportunity to test not only stress induced attraction (as discussed in brief under Plant Health), but trap-cropping as well. Our bean plot was approximately twelve feet from a short rock wall. On the other side of the rock wall was scrub growth for thirty feet, then woods. My plan was to plant those old beans in the ill-maintained scrub area just beyond the wall while the new beans were planted in the garden proper. The results, I feel, were very revealing. The stressed bean plants in the scrub area were absolutely inundated with both beetle species. Meanwhile, the beans in the garden were the cleanliest we’d ever seen. Nothing fancy here. No data to tabulate. Just an assumption being made by way of simple observation. The beetles were obviously more attracted by the stressed beans in the scrub than they were to the lush beans in the garden (which may partially have been due to the proximity of the test beans to the woods). We enjoyed a better-than-ever harvest due to the lack of pest pressure. Now here’s the kicker: we also got a small harvest from the bean plants in the scrub. No fuss. No muss. Not a waste of time. However, can conclusions really be drawn from such an unscientific experiment? Well, yeah, I think so. I’ve told other growers this story about our beans and they have, in keeping an open mind, tried similar tactics. The reports have been primarily positive.

Another great trap-crop, which I’ve written about before because it’s almost like setting up your own insectary, is eggplant. Eggplant is a whitefly magnet. Place an eggplant in the midst of your cash crop, say tomatoes, and wait until you see your first whitefly or two to appear. More than likely they will show up on the eggplant before the tomatoes. When this happens, inundate the eggplant with whitefly parasitoids — Encarsia formosa or Eretmocerus eremicus (to choose the appropriate parasitoid, know which whitefly species you’re dealing with-but this will covered in greater detail later). The parasitoids will often take off like wildfire using the eggplant as a breeding ground, reproducing with wild abandon. From this insectary sort of plant they stand a fair chance of establishing for the season. From this centralized plant they can protect the entire crop.

Now banker-crops

With trap-crops we are trying to lure pests-and biocontrols — to a given area so the war can take place there instead of in the cash crop. With banker-crops though, the plants used are intermingled with the cash crop. The reason for this is explained in what a banker-crop is and how it is supposed to work. Here’s an example: Tomato plants can be a difficult host plant for predatory mites to survive in-even though the pest mites seem to do well. (This probably has to due with the acclimation of the mites to the plant.) Bean plants, though, tend to be a very favorable host plant to predatory mites-as well as to the pest mites. Plant bean plants among the tomato plants. (In fact you may even trellis pole bean plants on the tomato plants.) The reason is simple. The predatory mites like Phytoseiulus persimilis don’t do well, as said, on the tomatoes, but do do well on the beans, and now they have a place, right there in the crop being protected, to prosper. Not rocket science, but not too obvious either.

On this web site I’m not going to define all the possible crop mixes of trap- and banker-crops. I’ll leave that to you, the grower. You know plants and I’m fully confident you can put two and two together and come up with your own solutions. I’m not trying to provide all the answers on this website, I’m just trying to point you in the right direction. Food for thought is all; I’m not serving up a seven course meal.

Education

This was discussed in some detail on the The Transition II page. But here’s some tidbits: read up, brush up, talk to those in the know (including your supplier of choice) and get out there and do it. There’s no teacher like experience, but in order to get some, you’ll have to start. Remember, learning by doing is a lesson well remembered.

One big part of these pages — as it appeared in the old edition of the Green Methods Manual — was scouting. And guess what? It is so important, it gets a page, or two all to itself on this web site. Read on…

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