At the urging of one of the biological pest control agent producers we work with, we have decided to bring on board a somewhat newer strain of our popular whitefly parasitoid, Encarsia formosa. Specifically, we’ve added what is known as the Nile Delta strain of E. formosa.
The primary advantage of the Nile Delta strain is that it had been adapted — beginning in 1997 — to the Bemisia spp.: B. argentifolii and B. tabaci. Depending on who you ask, these are the silverleaf and sweet potato whitefly species, respectively. Our regular E. formosa don’t possess this adaptation, sticking to parasitizing Trialeurodes vaporariorum, the greenhouse1 whitefly species. Our normal strain can adapt to these other species, but, based on producer input, it can take up to seven generations to happen and seven generations is much too long to wait for this process.
In the past, if one didn’t know what kind of whitefly to expect in their operation, then using a mix of both our regular Encarsia formosa and Eretmocerus eremicus for prevention was recommended. Now that we have the Nile Delta strain, growers can save a little money by being able to purchase one parasitoid species instead of two for their preventive needs. Please note, however, we still recommend learning which whitefly species you have and employing the proper parasitoid for the job.
The Nile Delta strain is new to us in regards to how effective it is and what you, our customers, will think about it. Thus, use it experimentally and please give us your feedback. For those of you with the common greenhouse whitefly species, we still suggest you use our regular E. formosa on cards. The are less expensive and proven by being time tested.
Want to try out our E. formosa Nile Delta strain? It’s available right now. Please see this online shop entry. You may also give us a call at 603.942.8925 and order it by phone. Presently, release methodology and rates are the same as they are for our regular E. formosa parasitoid on hanging cards.
1. Note: The name greenhouse whitefly can be misleading. Any of the whitefly species mentioned in this article can be found in greenhouses, not just the greenhouse whitefly. In other words, if you have whiteflies in your greenhouse, you cannot safely assume they are “greenhouse” whiteflies.
