Normally I don’t do garden or plant pest articles and concentrate solely on house hold pests but these little buggers get me so riled up every couple of years and I just know there are others out there who have been as frustrated as I was. Whiteflies in fact aren’t a true fly but are related to scale and mealy bugs but I purposely put this article in the gnat and fly topic area just to make it easier for people to find. In the end who the heck cares what family they’re in when you’ve got literally hundreds of thousands filling the air seemingly out of nowhere and your plants are wilting? You just want them GONE!
Quick bio before we kill em
There are two basic kinds of whiteflies you and I will deal with mostly and they are the Green House & the Citrus. As the names imply this is where you can often find these two critters hanging out but don’t limit them to the confines of their names especially the Citrus. I find whiteflies on all sorts of bushes and trees. Many people discover they have this dreaded pest when they are watering and fluttering clouds of little white moth like creatures go floating by. The waves of this airborne dandruff can be endless at times and they do look harmless so you may just wonder to yourself, “how much of a problem could they be?” Short of that you can discover you have this destructive pest when almost over night you find most of your bushes leaves on the ground and your plant is all but dead. That’s when it hits you and it’s time to break out your arsenal.
Whiteflies are found just about everywhere and are active all year round except in the northern states where they go dormant for the winter. To find the fly you need to look on the underside of the leaves since that is where the female lays her eggs, the young feed and the adults all seem to hang out. The eggs hatch in about 10 days or so and the nymph immediately begins feeding. They have piercing mouth parts so they suck the juices from the leaf and damage is not immediate. They excrete a honeydew substance which can get pretty thick at times causing more damage to the plant by covering it with ‘sooty mold.’ More importantly this ‘poo’ invites other nasty bugs to the party and your problem can soon become two fold or more, ants wasps and others often move in for the free meal. From egg to adult can be in as little time as month but the cycle can also take over a year in unfavorable conditions. Plants affected by whiteflies quickly become ragged looking and die if the infestation is left un-checked.
What works?- You do
Ok, so the $64,000.00 question is what can I do about the whitefly and I’ll bet many of you reading this have tried many approaches. Insecticidal soaps work well or soap in general because it smothers the nymphs and keeps the adults from flying so they lay less eggs. (kills them too) The trick is to be thorough however and make sure to spray the underside of the leaves. Now other insecticides are also labeled for whiteflies and indeed work pretty well but the problem I always have is trying to effectively get the spray where it needs to go. Once you try spraying upside down of sorts you’ll know what I mean. It’s very difficult and messy to do a thorough job in a thick bush and if the plant is 10 feet high or taller it can be almost impossible with simple hand held equipment. Add to this you’re gonna have to re-spray in about 10 days (cause your spray won’t get the eggs) and you just might be ready to throw up the white flag.
Not so fast-take the easy route
Imidacloprid is a great chemical that has a lot of uses and it is a systemic approach which can eliminate all that messy spray. The product name that is labeled for whiteflies is Merit but many termite technicians know it better as Premise, both are essentially the same product but Merit includes whiteflies on the label while Premise does not. (last time I checked) Application is very easy and it even comes in a granular form. The idea is to put the product down around the roots, water in and let your plant do the rest. Once the imidaclprid is taken up by the roots it basically makes your bush a toxic plant to bugs and bada bing, problem solved. Imidaclprid has a low toxicity to mammals so don’t let my use of the word toxic scare you. How the product works is it interferes with the insects nervous system and affects their mouth parts by paralyzing them-basically the insect starves to death. While you will pay dearly for this product it does go along way so definitely follow the label directions even if it only recommends a teaspoon per 10 gallons, it’ll work my friend trust me.
Raise the checkered flag
The other great thing about Imidaclprid is you won’t need to use years and years in a row. Nothing lasts forever and of course there are exceptions but I find that applying Merit every couple of years or only as needed is more than enough. It’s been 2 years since I used it last and it looks like I’ll be needing to run to the store here pretty soon. Either that or I need stronger dandruff shampoo because I’m seeing clouds of the white stuff floating by every time I get out into the breeze.