Whitefly are small well….white flies…. They live and lay eggs on the underside of leaves and besides being annoying and unsightly, they feed on the sap of the tree. This is bad.
If left unchecked they will kill off part of your tree. Recently upon working on a Duranta, I discovered it had an infestation. This particular tree has had a few infestations. They love this tree, as my others in the garden have no problem with whitefly.
Interesting isn’t it?
If you are newer to bonsai, or growing plants in general you will notice that certain trees are susceptible to certain pests/diseases. This Duranta’s weakness is whitefly.
The flies love the hot weather and come around hard and in full swing every spring/summer. They are amazing at hiding as well. Here is a picture of the tree with an infestation:
It looks healthy, but whitefly live and breed on the underside of the leaves. You can’t see them typically.
This is early on the tree above, but if the infestation is bad it will also lead to black sooty mold and a nasty looking tree. That is another thing….if you have sooty mold on your trees it’s a sign of insects.
When the flies eat the sap, naturally they have to excrete it. that sugary poop is what causes the mold to grow. So if you cure whitefly you get rid of the mold.
Here is a small infestation on a leaf:
It looks like white dust on the underside of the leaves. You’ll also notice black spots on the middle. Now this leaf still looks healthy because this is a small infestation but, they will cover the entire underside of a trees leaves and take all the sap.
The first sign that your trees have them won’t be on the trees. The signs will be in air. If you see small white flies around your garden, they are somewhere as they stay close to the host plant.
These things are small. Their body length usually measures only 1 to 2 millimeters. So they won’t be obvious at first.
Here is a close up of the fly from Wikipedia:
Controlling them is a huge pain in the butt. If you’ve had an infestation you know what I mean. It is doable though so don’t give up. They are pretty resistant to chemicals but what works best is simple. Insecticidal Soap. Much more complicated than it sounds.
The one above is a good one that I have used by Garden Safe, but with so many trees I make my own soap. It’s fairly easy. I use 2 tablespoons of Dawn dish detergent Original per gallon. The Blue one.
If you have less than 10 trees those little spray bottles are fine…but anything more I suggest making your own and using a pressure sprayer…much faster and easier!
Now this stuff is basically 100% safe even for organic farming, so not much to worry about. Basically, it’s a soapy mixture and what it does is absorb through the insects body, killing them.
Whitefly are soft bodied bugs, and because this isn’t a “chemical” application per se they can’t build immunity to it. This will also kill other soft bodied insects as well. Such as the dreaded Spider mites!
Like most pests one application is not enough and never will be. The key is multiple applications based on their life cycle. You can definitely research this more in depth, but in a nut shell:
The first time you spray you will kill the adult pests. However keep in mind, there are…and will be eggs, whether you see them or not.
Now, once those eggs hatch you must kill them before they lay eggs again.
So when do you spray?
What has worked best for me is spraying 1 time a week for 3 weeks in a row. I will also “preventative spray” even if there are no issues a few times during the summer and spring just to be safe.
If you have had issues hope this post helped and cheers to healthy trees!!!