Eretmocerus eremicus =californicus, what we the “B-Whitefly” or “Q-Type” parasitoid, is used for the prevention and low-infestation management of Bemisia spp. whiteflies. 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
These 0.8 mm. mini-wasps are best used for preventing the establishment of the silverleaf and sweet potato whitefly (the Bemisia species, B. argentifolii and B. tabaci, respectively), though our new Nile Delta strain of Encarsia formosa may help. They can also tackle minor to medium infestations. And, if established to a degree, they can adequately protect a crop throughout the season. (If you have greenhouse whitefly, Trialeurodes vaporariorum, use E. formosa.) E. eremicus are supplied as pupae protected in their host whitefly scales (pupae). These parasitized scales are supplied loose in a bottle with bran flakes which can be distributed throughout the crop, plain without the bran, in blister-pack hanging cards. [Intro]
Life-style
Eretmocerus eremicus, as parasitoids, work by laying eggs. But unlike E. formosa, which lay their eggs in the 2nd through 4th immature whitefly stages, E. eremicus females lay their eggs underneath those same stages, with a preference for the 2nd instar (stage). The wasps’ larvae which hatch from the eggs begin to enter the host and thus slowly weaken and kill the developing whiteflies from the outside-in (ectoparasitism). This causes noticeable host changes (see Scouting). And each female wasp (which equals 50-65% of the total release) can do this to up to 150 immature whiteflies! The life-span of these parasitoids is roughly 18 days in their immature stages, then for an currently undetermined period of time as yellow-colored adults. The conditions for optimum performance will be between 70-95°F with a relative humidity of 60% or less. 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. Higher temperatures, however, don’t seem to critically impact the performance of these mini-wasps (see Benefits, next). [Intro]
Benefits
These parasitoids, being native to America’s desert region, can handle high daytime temperatures, supposedly up to 113°F, as well as cold nighttime temps. These wasps are easily noticed when developing — though not as much so as E. formosa — making scouting a little easier (see Scouting). Host-feeding activity runs high with this species. It is more than an added bonus; these parasitoids could almost be regarded as predators. [Intro]
Drawbacks
E. eremicus are a bit on the pricey side, at least right now. With increased usage and subsequent demand, however, prices may drop (and they have some since this was first written in 1997-98). Honeydew levels, if high enough, might interfere with their performance. A couple of different things can play a role (see Advisories). I still lack experience with this species. I, therefore, need your assistance: tell me of your experiences so that I can pass on the knowledge. (Of course I ask this of you in regards to all the bugs discussed.) [Intro]
Scouting
The scales, when parasitized, begin to reveal the developing wasps inside. Like it is with E. formosa, the whitefly pupa does darken as the parasitoid within develops, a darkening gold in this case, and not as much so as to conceal the larval wasp. It may be seen in the right conditions and at the right time. Yellow sticky traps might not be able to be used at times (see Advisories, next). [Intro]
Advisories
Yellow sticky traps might have to be removed prior to releasing these mini-wasps, but I’m uncertain and ask that you closely observe the traps if they remain in use. If you need to monitor for thrips, try using blue traps. If yellow traps must be used for fungus gnats, etc., you might need to hang them for only two days per week. To reduce adult whitefly levels, fast, instead of placing about a million sticky traps up, Suck ‘em up!
Ants, if present, should probably be controlled. They will defend whiteflies from predators and parasites to protect their honeydew food (the excrement of whiteflies, ick!). Use barrier products or boric acid products to control the ants. If your planting doesn’t have any ants, check to be sure that the honeydew isn’t too heavy. This may prove to be a hindrance to the parasitoids’ performance; they may spend too much time cleaning themselves. Washing the plants with soap and water — at the highest possible pressure — may help reduce the amount of honeydew. Some crops, due to their excessive whitefly susceptibility, may require special IPM attention, higher release rates and/or more frequently scheduled releases (closer intervals). [Intro]
Usages
On most greenhouse crops and interior situations is where I recommend employing these parasitoids. I am not familiar with any other practical uses. However, I do encourage you to try them anywhere for the sake of experimentation and thus even offer rates for such. [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 E. eremicus on hanging cards online. [Intro]
