lilac and backyard full of whiteflies


First off, I loved your info on whiteflies.  Found it by using a Dogpile web search and it was excellent.  I am a homeowner and also a landscape designer – so have training and experience in pest management, and was able to understand the article very clearly and found it very informative.  However, I’m writing because I am a bit freaked out – my backyard has a major – and I mean major! – infestation of whiteflies!  I have never seen anything like this in my twenty years of landscape and am very unsure how to proceed.  I am a designer only and do not have a spray license – and while I own a spray tank system for the spraying of chemicals at my home I am a bit intimidated at mixing a cocktail for these buggers. Long and short of it – I had one large 10×10 California lilac that had whiteflies last year – I thought I had eradicated them before winter but apparently they continued a happy home there over winter and continued to multiply.  I have had to cut that plant back last month to 5×5 as it was mostly dead branches, and dosed it in a supposed systemic treatment.  Seemed to work for a while but, new group of bugs is back on that plant as well as over pretty much everything in my yard that is tasty – likely in my neighbor’s yards too although I will not be asking!  They are so prolific I can see them flying around pretty much anytime.  That scares me!  I am interested in proceeding with some of the treatments you recommended but need to know how much to apply and how I can do so safely.  I can skip right on through to the ‘get down to business’ approach, because I clearly have quite a serious problem on my hands – when I touch most any shrub in my yard, a pile of whiteflies comes out.  Shame on me for not realizing how serious they can get – I got my hort training in the Midwest but now live in the Northwest – they don’t go quite dormant in winters here obviously!!  Silly me…. now I have to do something before the buggers take over the neighborhood.  Are the treatments you mentioned systemic, or do they require reapplication?  Anyhow – too many questions to keep typing a novel – either reply to this w/ your ideas and or call me.  Are your products sold here in Portland OR?  Hope so!  If not, I’d be glad to recommend to a few nurseries I work with!  Looking forward to hearing from you…  L.S.

First, thanks for all your kind words. We strive to post the most comprehensive information and recommend the best products available when dealing with any pest and whiteflies are no exception. Having dealt with some problems with them in the past, I know first hand what it takes to knock out a strong infestation. The good news is you can keep them under control with the right products.

As explained in our WHITE FLY ARTICLE, the real secret with whiteflies is being able to stop the reproducing on host plants. Though you can achieve this with systemic formulations, they take a long time to permeate and impact the current situation. Products like MERIT WP will work if used continuously but at this point it’s obvious you need to do a good spraying if you wish to get immediate results.

And to keep it simple, I suggest you go with the best. A combination of BIFEN, NYLAR and SPREADER STICKER will take care of any problem. I have been able to solve every problem here in GA with this mix. Odorless and long lasting, both the Bifen and the Nylar will work together to kill what’s active and prevent successful reproduction of any nuisance insect you find. In most cases I only had to treat once but to make sure they didn’t return on certain plants (like my privet), I started treating every spring and fall. This twice a year ordeal has kept them away for good and I’m sure it will work for your problem too.

Direct links to the information and products mentioned above are here:


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