An organic spray for Aphids and other insects on roses
I wrote this Article yesterday for my blog, since many seems to be "bugged" these days: Click on Images to enlarge:
Roses like many other ornamental garden plants, are attacked by insects that damage the plants. The problem with rose gardens are, that they are a mono culture. In mono cultures there are no biological diversity of plants, that create natural habitats for beneficial insects that can keep the number of harmful insects down. A mixed planting with roses, trees, shrubs, bulbs, perennials, annuals and semi-annuals, have more biodiversity and attract more of the beneficial insects that can keep the number of harmful insects at bay.
It is becoming more and more unacceptable for gardeners to use chemical toxic insecticides. The environmentally long term effects of many chemical insecticides are unknown and many are also toxic to gardeners, who have to wear protection gear, when spraying these insecticides.
One organic insecticide that has almost been forgotten is extracts of Chrysanthemum cinerariefolium or Dalmatian chrysanthemums. The active component in the extracts are pyrethrum or natural-pyrethrins. They are neuro-toxic to insects and kill all insect hit by a spray containing natural-pyrethrins. Natural-pyrethrins are biodegradable and short acting since its is broken down by UV light and Oxygen. They are safe to use on vegetables and they are safe to eat after 24 hours. (Do wash them).I used to buy a few pounds of dried flowerheads of Chrysanthemum cinerariefolium and made a tea for my little pressure sprayer. I sprayed shoots that had very badly infested with aphids and leaves infected with leafhopper and rose-slugs (Sawfly). The effects are remarkable! Take a look at this tip of a rose-shoot infested with aphids:
And then take a look at the same shoot sprayed with natural-pyrethrin 7 days later:
One might say: Well aphids can just be sprayed a way with a jet of water, well true if repeated a few times that will help! But what if you have 200 or more roses? Or even just 50, it would be a waste of water and take an absurd amount of time. Also many ornamental plants would look horrible after been sprayed with jets of water! I also do not like insecticidal soaps since I have experienced follicular burns.
Aphids in large numbers suck the life out of young rose shoots and cause deformed flowers and leaves. They also increase the risk of fungal disease by the damage they do to the plant and the honeydew they excrete. Take a look at this rose shoot:
That is above the tolerance I have for aphids on roses! I either make the pyretrum tea and spray or use one of the natural extracts that can now be bought from various companies. It is also possible to grow the Chrysanthemums yourself or buy the dried flowerheads and make they tea used to spray:
For one half liter / about 16 fl OZ of water I use 3 table spoons of dried flowerheads of Chrysanthemum cinerariefolium and slowly warm the tea in a small pot, until it becomes hot but not boiling. I allow the tea to cool with the flowerheads still in. When Cooled I filter away the flowerheads and poor the tea in my little pressure sprayer.
I spray shoots and plants heavy infested with aphids. I do not nuke the entire garden or use bigger pressure sprayers with this pyrethrum tea. If I did that I would kill too many beneficial insects too. The idea is to keep a balance and target specific insects that are causing a problem. I do that by spraying areas where I see the insects I want to get rid of. I am careful not to hit fx. bees. If plants are infested with roseslugs or leafhoppers, I do use a bigger pressure sprayer, that is better at creating a fine mist and has a longer handle so I can spray the underside of the leaves too. I only spray about 3 times every year. I see plenty of beneficial insects and there are still lots of aphids left them and birds like sparrows and tits eats a lot of them too. I have nesting boxes for these garden helpers:
Natural Pyrethrum and pyrethrins tea and extract have a very pleasant smell of chrysanthemums. Some are however allergic to chrysanthemums, and the spray can cause skin irritation and irritate the eyes. I have never experienced any of that, but do be careful when spraying! Just because it is organic does not mean it is harmless. Also make sure not spray around ponds, since it will kill aquatic insects too. Natural pyrethrins is useful against many different insects on many different plants.