Massive whitefly problem in border garden
BeeBlue
Posts: 1
I have a sensitive problem in that I have a large infestation of whitefly starting from last summer which has killed off almost all of my smaller plants. I let it go without killing them off last year because I have created a small conservation area for butterflies, moths and bees in the city of Brighton. I have been to gardening centres to look for organic pesticides that will NOT kill caterpillars as well. I could not find any. I have done the soapy water thing to my house plants which were also infested due to open windows But the area is too vast to spray all the plants outdoors. Spring has arrived and I want to sort my garden out but can't do a thing until this whitefly are gone. Please please help!
What can I do to rid the whitefly but protect my greedy little caterpillars and newly wakened bees? Any advice would be greatly appreciated.
Currently looking into ladybirds as an option. Will this be effective???
Posts
Infestations do occur naturally but what usually happens is that predators appear and have a feast. Problems appear when there is an imbalance such as a monoculture, which attracts more pests than can be munched by the hungriest of predators. I have a herb bed to attract bees. My sage grew too big, and was covered in small white flies so I pulled it out, it was not worth the trouble. The whitefly went. Last year I had some blackfly outbreaks on plants, but they did not last long because my herbs pull in the predators. So it sounds as if something is wrong with your garden. Which plants do you have? Where are the whitefly worst?
From past experience weeds such as mallow and sweet pea pull in the hover flies, which eat aphids. And weeds are often good for attracting butterflies too. Marjoram and lavender are good too. I would say you need to add more predator friendly plants. That is only a guess without knowing more. But something is wrong.
The only thing which will likely work in the way you want is to introduce a whitefly-specific predator. Encarsia formosa is a tiny wasp which will prey on them. Eretmocerus Eremicus is another similar wasp. You may need to try both.
Most of the common predators such as lacewings, ladybirds and hoverflies predate on aphids, not whitefly and will ignore them.
The whitefly predators are only effective when it is warm enough and are normally used in greenhouses as that is where most whitefly infestations occur. As you are in Brighton there is a good chance that these will work outside in a few weeks time when night-time temperatures are higher and more stable, especially if your garden is sheltered. There are several online suppliers.