These little breeders have been having a banquet on some of my Dahlias. They go for the soft new shoots and nascent flower stems which must be easy to get their teeth into. For some reason they have been quite selective on the plants they choose (As has been the spray I have used in a prophylactic manner). I hope the rest of the summer is black fly free but you never know.

Why are Black Fly Bad News

• Black fly aphids or thrips are common sap-sucking insects. 
• They are unsightly and look like they can do serious damage to plants.
• As sap sucking insects they can create a lack of vigour and damage growth.
  
• Insect secretions can go mouldy and add further problems to the dahlias
• In severe cases viruses can be transferred to plants by these insects.

Lulled into a false sense of security by the low level of greenfly around my garden I wasn’t expecting black fly. I only left my dahlias alone for a few days and the flies multiplied like rabbits. I am on a more frequent look out patrol now. The muggy weather is one reason for the outbreak of black fly.