Page Intro: Iphiseius =Amblyseius degenerans, what we call the “Dark” mite, is used for the prevention and management of various thrips (and even some spider mites). On this page you will find a description, life-cycle info, benefits, drawbacks, scouting info, advisories, usages, and other good stuff such as release rates.
Description
Persistent little predators, that’s what they are I think. The jury’s still out on this one. Unless you’re a pepper grower, or have a system capable of supporting long-term growth of this species, then I know these predators are top-notch. I also know, that regardless of crop, they love thrips, spider mites, and pollen (see Drawbacks and Advisories). I. degenerans are shipped as adults, with some immatures and eggs as well, at times (the latter are not part of the guaranteed count). They’re provided in vermiculite, so distribution is a snap, though they used to be available on leaves which had a lot of potential. I. degenerans can potentially prevent thrips from becoming intolerable. And in the right conditions, they can establish themselves and provide ongoing control through continued preventive activities. Some of the species they can devour include all of the species controlled by Neoseiulus cucumeris. This possibly includes the mite species as well. Other mites can also fall prey to I. degenerans, some of the Tetranychus spp. for example. I do not recommend using these mites for other pests at this time, unless it is for the sake of experimentation. I believe control of other pests might not be obtainable with typical dark mite releases. Coincidental cross-predation should be regarded as a bonus of the application and nothing more. Conduct your own trials if you wish. Get back to me please; let me know how well they work; tell me what you saw. Like most of the recommendations in this Primer, I learn these truths from my contacts’ experiences. (Others are based on producer recommendations, my company’s own research trials, etc.) [Intro]
Life-style
The slick-looking, tiny 0.7 mm. dark-brown (they appear to be black) adult female mites lay eggs amongst thrips’ concentrations and close to pollen sources. The eggs hatch into super small larvae which develop into nymphal forms before reaching adulthood. These, too, are effective predators, consuming many immature thrips. The life-span of these predators is about 9 days in their immature stages, then around 30 days as adults. The conditions for optimum performance will be between 65-85°F with a relative humidity of between 60-85%. But these are optimum conditions, and not necessarily a prerequisite of successful implementation. Please note, however, cooler temperatures will hamper reproduction and development a certain degree. [Intro]
Benefits
These predators enjoy snacking on available pollen (see Drawbacks and Advisories.) This helps them be an efficient long-term preventive agent as well as a potential curative one, as already discussed. These mites are a bit on the pricy side. However, because of their ability to establish, they can be extremely economical. This is currently the case for sweet pepper production. Pepper growers are having extraordinary success. [Intro]
Drawbacks
These predators may actually like pollen over pests in some cases. This should be considered when applying this species. Close observation is definitely warranted (see Advisories). I’m still investigating this possibility. For one thing, only a small segment of my contacts have tried them. And the results have been there, but not definitively. Historically, supply has been shaky. This was a drawback. Perhaps it still may be at times. The progress with improved production techniques thus far, though, is promising. Availability may not be a problem this year. Extensive webbing from spider mites, if present, may hamper the efficiency of the dark mites. I would still use them in a dual-pest situation like this, though. Especially since they will eat the mites, too. But, first, be a webwiper. Harsh climates cannot support this species. With exception to indoor applications, northern use outdoors is probably not an economical option. [Intro]
Scouting
Finding I. degenerans on the plants, because of their dark, contrasting color, is relatively easy for the amateur scout. But, nevertheless, it can take some practice, the mites are pretty small. In addition to looking for predators, we suggest simply monitoring the thrips levels. This is still the easier option. Monitoring thrips levels can be done two different ways: 1) use blue, yellow or hot pink sticky traps to capture adults which can be counted weekly and/or; 2) use the “paper method” by gently shaking the plant over a white piece of paper on which they’ll show up nicely. Try the latter on a corn plant this summer, tap out the tassels if you really want to see some thrips. [Intro]
Advisories
Flowering, pollen producing plants may be a plus, maybe. It is suspected that the mites might consume pollen more readily than pests. On this I am not yet totally clear. Each datum received will be passed on to my contacts; as I learn, so will you. Until I have the answers, I’ll encourage you to provide pollen or a source thereof, to these mites. Just avoid providing too much; let’s try keeping the mites lean and mean. There may be an I. degenerans compatibility issue when used with N. cucumeris. Used together, this pair is under suspicion: the I. degenerans is suspected of being able to run N. cucumeris out of town. [Intro]
Usages
Greenhouses (especially on greenhouse peppers), interiors, and the like, are where these mites are most often used. They can also be used in some nurseries for outdoor thrips control (but, please, only as a trial). As noted in Drawbacks:
“Harsh climates cannot support this species. With exception to indoor applications, northern use outdoors is probably not an economical option.” — We said it
[Intro]
Rates, Instructions, and Purchase
Need more information? Check out our release rates or our short-term storage, handling, and release instructions. These predators are no longer commercially available. [Intro]
