The best way to control and ultimately get rid of greenfly may be to feed your ants, says gardening expert Doug Stewart.
It sounds an unlikely solution, doesn't it? However, the best way to control greenfly and blackfly on fruit trees, could be to make up a sugary solution and feed it to the ants in your garden, according to the latest research. Unlikely as this may sound; it could be just the solution we have been waiting for as gardeners. There is something plant scientists call ant-aphid (greenfly) mutualism. This is a complex way of explaining that aphids, who are really good at extracting the sweet juices running through a plant's stem, digest some of it and exude the rest, which often falls to the ground in the summer, making both cars, patios and garden furniture sticky.
Ants have tapped into this wonderful sugary food source, collecting it from the aphids. Soon they become addicted to this sugary delight. While the odd aphid might also nibble at a little bit of protein, the real damage occurs as the ants move the aphids around the infected plants, in essence setting up small aphid farms. The ants also protect the aphids from natural predators and parasites which would otherwise naturally control the aphid population. Researchers found that once the ants were removed from the scene, the aphids quickly fell prey to predators, and are attacked and consumed.
Something as simple as a sugar solution being made available to the ants stops them farming the aphids and so reduces the damage to fruit trees. The research was presented by Professor Jerry Cross to fruit growers at the East Malling Research Association in association with the Horticultural Development Company. He recommends the use of a 30% sucrose solution, stabilised with the sugar alcohol sorbitol, which should be made available to the ants just before blossom and kept available for 4 - 6 weeks.
For those of us trying to garden organically, pull on your overalls or work trousers, and focus on using nematodes for slug control, encouraging beneficial insects with beds of nectar-rich flowers, and placing small bottles of sugar solution at the base of fruit trees - could be the trend to follow in 2018.