Helpful Hints and Tidbits You Should Know
Fall Biocontrols Use
Many growers will adopt and even cling to a misunderstanding that can cost them money in myriad ways. Specifically: Spring is the time for bugs and, thus, that’s the time for fighting them. Having these thoughts can be downright dangerous. Spring is a time for bugs and it is a good time to do battle with them. But it’s not the only time of year for pest control, and in some cases it’s not even the best time of year.
Summer is another period of activity. And if you have a greenhouse or other weather-preserving environment, you can even include the mid-winter. But there’s one more very important season: Autumn. Fall is a great time to level the playing field, or in some case even better, flatten the competition. Think about it for a moment. As we come indoors for the winter, so do many pests, or at least they try. Try out this scenario:
Let’s say you fired up your greenhouse in mid-winter, , bringing the temperatures up from a holding state to an active one. Almost immediately you discovered some pests. It seemed as if you applied heat and water and brought about life. And it seemed that way because that’s what happened. You fought them back, though, and won yourself a reprieve. Now let’s fast-forward a bit.
Mid-summer came. You were pretty much sold out of everything you had except your stock plants. Those spent the summer outside basking in the warm sunshine, busily redefining the very meaning of plant heath. During this time you had buttoned up your greenhouse in hopes of baking the contents in an effort to kill pests, diseases, and weeds. That, of course, went as planned. A good baking is always a good idea.
So now here we are at the present time. You are starting to move your stock plant material inside to keep it all alive — and to try and retain that summer flush. You do this so you can take cuttings in the mid winter to start your crops for next spring. You do this because your plants need to stay protected for the winter. Very much the way many pests do. They seek cover and protection from the brutality of winter. Small numbers of good bugs do this as well.
Inside your greenhouse, due to the summer baking. You have no pests, but as you move your plants inside, other creatures are making their way inside as well. The conditions inside are now not only habitable, but quite tempting too. Warmth, sunshine, still watering. Wow, in the eyes of the pests it must be like spring all over again.
Is this the course you run? Is this your cycle? If so, fall is a great time to introduce biocontrols into a greenhouse. They will feed during the fall, awaken early in the mid-winter just like the other critters inside your winter greenhouse, and provide you with a presence and small population of good guys when and where none previously existed.
This can also happen to a degree in some field crops like strawberries. Putting out a hardy mite like Neoseiulus fallacis into a strawberry crop will help disable the two-spotted mite population in the field come spring. Moreover, you will begin the season with some predators.
Yes, fall’s another time for the good fight. Bear this in mind now as now’s a great time to act and prepare for next year.
In the world of biocontrol and integrated pest management, as it is in the other fields of science, testing is an on-going endeavor. This takes place on different levels: Producers, distributors and dealers (some, like us, actually do some independent testing), and end-users like yourself, perhaps. The end-user testing is what we’re concerned about here.
End-users of these products test often. Rarely are these tests official or structured, though. And often there’s no concrete way to gauge the results and properly determine what is happening and why. We hear things like… “I’m going to test these guys out and see what happens.” This is meant to broaden one’s knowledge and determine a future course of action for the one conducting the “test,” but it is often an ill-attempt.
While this is all fine and good, and we do encourage experimentation, of course, going about it in a haphazard fashion can produce erroneous and misleading results, and often simply obscure the facts. Improper testing can confuse the tester sometimes to the point of being damaging.
Testing, trials and research, and experimentation need to be planned and conducted in such a way that the tester will know what to look for to properly gauge the results. It is for this reason we offer “Scouting” information under each biocontrol agent on this site. We realize there is a lot of “testing” going on and we are aware that those conducting said tests have at least a little something to go on. It’s difficult to offer more concise information due to myriad variables and the sheer complexity of some of the possible tests.
Another big problem with testing — one we hear often — is that some people try to over test. They test too many things at once which all but obliterates any useful data that could have been obtained. Case in point: A grower has a certain pest. Let’s call it Weirdicus buggii. He or she is fearful of this pest, has little to no knowledge of it and what it can do and how it behaves, and has no idea how to control it. The grower contacts us wanting to try four or five different approaches to controlling it. This is a safety for the grower as they choose not to take chances and are stacking the odds in their favor by hoping at least one of the tests produce favorable results. The problem with this approach is if they do get control of W. buggii, it’s likely they won’t know whet did the trick. If this cannot be determined, the following year they will find they have to employ all five controls again in order to get the same results.
It’s chancier trying one control at a time, especially biocontrols since they tend to work more slowly than chemical controls, but the results will be more clear. There will be no confusion as to what did what. Try this when you do your testing. Know the pest, know what’s normal and what’s not, try to use one control at a time until you know what works, and try to go about the whole thing in a structured and logical way. Document the progress and variables of the test. The benefits of such testing will be more available and the tester will be more empowered. It’s more of a gamble to follow these common rules of testing in some respects, but the useful information which can be obtained by doing so is far better than shooting from the hip.
I’ve heard it so many times yet I still ask now and then. This is the scenario: The phone rings and the grower on the other end tells me he has located a small grouping of aphids or something and wants to obtain some biocontrols to fix the problem. So far so good, he’s acting swiftly. I then casually ask if he squished the little group of aphids after he noted their existence. This is where things often go awry. He replies that he did not in fact do anything to the aphids. Sometimes I ask at this point, and sometimes I don’t, but… “Why not?! Why didn’t you squish the aphids?” Do it, if you see the pests deal with them, don’t rely on the bugs or the sprays when a quick pinch is such an obvious answer. Populations are generally easier to control, whether you’re spraying or using bugs, or even taking matters into your own hands, when pest numbers are low. Act when and where you have the chance. I know of no grower who’s “too big” to do this. It works, I tested it extensively a few summers ago, and the scale is irrelevant as it’s all proportionate. Just do it.
If growers have a lot* of two spotted mites, Tetranychus urticae, there should be a fair amount of webbing associated with them. Sometimes, though, this webbing is difficult to see if not viewed the right way or if viewing conditions are poor. Or — and this is an important one to the scout — if numbers are not yet high as some webbing should still be present as the colony of these pests develops. It is even more difficult to see when numbers are low. And this is the critical time (so as to avoid *scenario “A” — high numbers, lots of webbing).
I held the leaf up before my eyes. It looked clean without magnification. I then turned towards a good source of daylight and turned the leaf in such a way that I could look down the length of the leaf’s underside, right along the midrib. Imagine being really small and straddling the midrib like one would straddle a horse. That was the view I had. It was revealing.
I was surprised by what I saw: going from one leaf under-surface to its opposite, over the midrib, was webbing. Very fine webbing. It created a sort of tent, with the midrib being the “center pole,” if you will. Inside the tent of fine webbing were mites. Two-spotted mites, specifically. It was the very beginnings of an infestation. The grower, while dismayed by the discovery, was also happy to know about it before the webbing became obvious from all angles. So, in summary, be small, be real small, and straddle the midrib and have a look. You might find mites long before they want to be found.
If you have spider mites, specifically two-spotted mites and others which produce webbing, you can really give them a good swift kick in the pants by simply giving them a sponge bath. Take a sponge and dip it in a bucket filled with a non-detergent soap and warm water. Clean the affected plants, notably the webbed portions, focusing mostly on leaf undersides. The mite’s eggs and young are there in numbers so this is such a worthwhile activity. Try it, you’ll see. It delivers one heck of a blow to the mites. When you’re done with the clean-up, add some predatory mites to clean-up even more.
Note: The webbing I’m talking about primarily goes from leave underside, over the midrib, to the opposite leaf underside (though in really bad cases it can cover entire plant tops). If you see webbing strung along from plant to plant across spans of several inches to a few feet, that is probably spider webbing. Spiders are really good predators so leave them alone if at all possible.
If you ever touch your plants, or worse, simply stroll through your greenhouse only to stir up 100s or 1000s, or even tens of thousands of whiteflies, this is something you might want to try. Head back out of the greenhouse, run in fact (too depressing in there seeing all those pests). Grab your Shop Vac. If you don’t have one, buy one at your local hardware store; they’re under $20. I Think. Now, with Shop Vac in hand, head bravely back into that greenhouse and suck up all those airborne whitefly adults. Do take care not to suck up your plants so stick to the airborne pests. Someone can help by disturbing the plants as you go to encourage to whiteflies to take flight. This will put a big hurtin’ on the resident whitefly population so it is worth your effort. Go ahead, if the circumstances described are yours, this should now be on your Must-Do list.
For a long time we’ve known that thrips are attracted by scent as well as visual stimuli such as color. But now there may be a way to utilize this scent-attraction to help thrips trap themselves, thus removing them from the crop. One new way to do this, even though this still requires some more experimentation, is to soak plain old cotton balls in vanilla or almond extract and place them in the crop. Apparently thrips are quite attracted to these scents and will actually make their way into the cotton balls looking for the source. The good part is once they burrow into the cotton balls they find it nearly impossible to extricate themselves. This is a novel, inexpensive approach that can help reduce thrips numbers simply by way of trapping them.
Trapping Gnats with Potatoes
Need to scout for or trap fungus gnat larvae? Here’s a novel method: Use ¼" slices of raw potato to catch them. Here’s how: Place a slice of raw potato on the surface of the media on at least one pot per section for monitoring purposes, or place one slice on the surface of the media per pot (or several on beds). Allow the slices to rest undisturbed for one week, then flip them over to check for signs of life. The gnat larvae are attracted to the slices and will burrow inside of them, feeding as they go. The inspecting scout will be able to see the holes if not the actual larvae within the slices. If larvae are present, simply throw the slice away, being sure to do so in such a way that the larvae will be destroyed or at least not emerge in the environment from which they’re being removed. In any case, due to spoilage, be sure to change the slices weekly. Easy, inexpensive, yet effective.