Page Intro: Hypoaspis miles is a soil-dwelling mite capable of the prevention, control, and management of various thrips and soil pests. On this page you will find a description, life-cycle info, benefits, drawbacks, scouting info, advisories, usages, and other good stuff such as ordering.
Description
If at gunpoint I had to choose a favorite organism, Hypoaspis miles might be what I’d answer. Why? The reason is the organism’s use and potential — it’s fantastic. Not only are these mites predators of thrips’ prepupal and pupal stages, they are very effective fungus gnat predators as well. Now for the next question: If asked if there is one organism which should be employed in nearly every greenhouse or interiorscape, worldwide, what would I say? H. miles. And I’m not exaggerating. H. miles are shipped as adults, immatures and eggs in liter-size shaker canisters filled with a loose vermiculite carrier and a percentage of clean peat, and some bran added for good measure. In this form, H. miles are very easy to distribute in the crop. H. miles can help prevent thrips from becoming intolerable. They can also be instrumental in assisting another predator with the timely and efficient control of an outbreak. Some of the species they can devour are listed under the thrips predator, N. cucumeris. Moreover, by themselves, they can control all the fungus gnat species mentioned in the page on parasitic nematodes. And if that’s not enough, these little carnivores (meat eaters)/detrivores (recyclers) also eat springtails (species in the insect order Collembola). Currently under investigation is the potential for these mites to impact root mealybugs (Rhizoecus arabicus and other Pseudococcidae family members), sow bugs and pill bugs, also known as rolly-pollies (Portcellio spp. and Armadillidium vulgare, respectively), and even a fungus-eating mite (sp. unk.) found in some Shiitake mushroom production houses. The investigation is showing the most promise where the impact of the mushroom mite is concerned (in addition to great mushroom fly control). As for the rest, it’s still too early to tell. The control of sow bugs looks like it’s a lab thing only unfortunately. I’ve yet to hear positive feedback from the field. [Intro]
Life-style
These robust 0.8 mm. richly-colored tan to brown mites live, eat and reproduce in the soil or soilless medium in containers and planters and, on the walkways and floors of greenhouses (or on the Shiitake logs in the mushroom scenario). The H. miles females’ eggs — of which there are many — hatch into super small larvae which develop into tiny dark brown, almost black, nymphal forms before reaching adulthood. These, too, are fierce predators, consuming many pests, mostly the eggs and smaller larvae (first and second instar) of fungus gnats and the pupal stages of thrips. The life-span of these predators is about 13 days from egg to ever-after. But they reproduce profusely in what little time they have. The conditions for optimum performance will be between 60-72°F, and I’m talking about soil temperatures, with a relative humidity equal to that found in a friable, slightly moist medium, compost or soil. But these are optimum conditions, and not necessarily a prerequisite of successful implementation. Please note, however, considerably cooler temperatures will hamper reproduction and development a certain degree. [Intro]
Benefits
H. miles are very cost-effective. A little bit goes a long way and they can last such a long time. These predators, like Neoseiulus cucumeris, are supplied with some mold mites (Tyrophagus putrescentiae). These mold mites are merely a non-sustainable food source (but only after the contents are distributed, left in the bottle the mold mites will reproduce) for the predatory mites while they’re in transit and in storage. That’s right, storage, you can give a half-liter bottle to each interiorscape tech; the bottles store for two weeks — easily (longer but I’m not saying… don’t push it. The “Hypos” just go about their business, feeding on the mold mites and their own dead and miscellaneous stuff. Fair humidity in storage is helpful, and the techs can’t leave the bottles in their cars, etc. Other than that, “have Hypos will travel!” These predators are compatible with many —cides; a real plus in an Integrated Pest Management (IPM) program. Part of the reason for this is simple: these mites are protected in the soil during spraying. They do wander at night, though, so caution is still advisable. This wandering, however, has its advantages: the mites can establish themselves in the entire area usually. [Intro]
Drawbacks
You get a lot, but you have to use a lot. Good thing they’re inexpensive. These mites like humid conditions. Therefore, growers of some herbs, most cacti and some succulents may not have suitable soil conditions for these predators. They probably won’t have fungus gnats either. And as far as thrips…? Perhaps. H. miles can reduce thrips populations by only about 30%, but this isn’t necessarily the fault of the mites (see Advisories). [Intro]
Scouting
Using the paper method (discussed in greater detail under N. cucumeris’ Scouting) and yellow, blue and hot pink sticky traps to detect thrips is a sure way to progressively determine your predators’ efficacy. Using yellow sticky traps (lying sticky-side-up at surface level) and potato disks to monitor fungus gnat levels will do the same. Unless your scouting is really top-notch, you’ll probably miss most of the predators present in the soil or medium. But this doesn’t have to be the case. First look at the mites in the container. (They’re sometimes under the lid, if they’re not readily visible, try blowing gently into the bottle. More often than not this will bring them up from the terrifying vermiculite depths.) This way you may be better able to identify the mites later. Now, in the release site (this works best in other than small containerized plantings) place stones, small pieces of bark, etc. around the site. Then, during your weekly scouting rounds, you can flip over the “little shelters” to look for your beneficial mites. But it’s not unheard-of to find these tough survivors up to a year after a release. This isn’t always the case. It happens mostly in large planters and greenhouse floors (see Advisories, next). [Intro]
Advisories
For fungus gnat control, 6" pots and up are probably the best bet for containerized plant applications. If they’re smaller than that, we normally recommend parasitic nematodes (see Parasitic Nematodes). For thrips control, however, it is best to use the mites in nearly every application — but not alone. The thrips’ in-ground stages make up only a small percentage of their overall life-span. This is why the H. miles can only handle about 30% of the overall population. An above-ground predator, like one of the other organisms in this section, really should be used. However, let it be known that the impact of H. miles on this extremely pernicious pest is noticeable at worst. 30% is 30%! Do not rely entirely on the long-term establishment of H. miles. This happens, almost always to a certain extent, but not necessarily to such a degree that pest control can be maintained (see Rates). Multiple and regular releases are, like it is for our other biocontrols, recommended. One rule-of-thumb to consider: the bigger the container or release site the longer the interval between releases can potentially be (and thus fewer releases); and the opposite is true for smaller containers or growing areas. [Intro]
Usages
Greenhouses/interiors are where these mites are most often used. However, I’ve heard excellent reports from outdoor nurserymen who’ve had outstanding results. [Intro]
Rates, Instructions, and Purchase
Need more information? Check out our release rates or our short-term storage, handling, and release instructions. You may also purchase H. miles. [Intro]
