hi, i am getting loads of blackflies all on my plants, i don't like to use chemicals, so any suggestion plase
Wait. They disappear eventually.
hi, do they destroy your plants
It depends on what you mean by destroy. A healthy plant can withstand an attack of blackfly. They suck the sap and, rarely, may pass on viruses to the plant. But it's the same as a healthy human being bitten by mosqitoes - they suck some blood and leave you feeling less chirpy than you were before but you get over it. Unless you get malaria, but that's as rare for us as a virus for a plant from a blackfly.
After the blackfly have been eaten by a bird or another insect the plant sometimes looks a bit lopsided where they have been. But it grows new leaves and regains its composure.
I have some cardoons that are black for the top 9 or 10 inches but the flowers will be OK so I'm just leaving them alone.
They won't destroy them but can seriously weaken them esp. veges. BUT the predators are coming, late this year but more seem to be showing up now. Look for ladybirds, spiders, hoverflies and a lot of the tit birds eat aphids too. Any ants crawling up and down the stems? They "milk" the aphids in exchange for protection so you need to deal with them too. The hose really is the best option if you don't like using chemicals but do that a few times and stop then go move some spiders and ladybirds onto the plants and hang some bird food near worst affected plants.
Thanks for the advice addict I have a serious aphid problem but I had no clue what to do and didn't want to disturb the ants so I just let them be. Now I will try and see to those ants, so they don;t encourage the aphids even more.
You're welcome comp You don't know until you know lol. I find it fascinating to watch the insects in the garden. How they all interact with each other and what eats what. Once watched a wasp and a honey bee having a fight. Sadly the wasp won by decapitaing the bee! Have noticed that the ants don't have any affect on the ladybirds. They must have little suits of armour on as seem totally oblivious to any attack from ants.
Aphids can be the cause of honeydew fungus on some plants. They secrete a sticky substance that adheres to the leaves of the plant below them. This then turns black as the fungus takes a hold. I tend to use a hose, support the plant with my fingers and wash the apids off. Have let them alone on my runner beans this year as there are plenty of ladybird larvae on the plants and I don't want them to go hungry. They're certainly keeping their numbers down!