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BLACK SPOT AND GREEN FLY ON ROSES

United Kingdom Gb

I would like to spray my roses for black spot and green fly but all the named sprays have a warning that they are dangerous for bees. What can I use that is safe?




Answers

 

Firstly let me say it is so nice to know that people are taking notice of the warnings now. We have so few bees this year it is tragic.
There are various ways of keeping your roses blackspot free...
Feed the soil they are growing in. Make sure they have composted manure dug in around the base twice a year. First in March and then again before the second flush around June.

Prune roses and make cuts that slope away from the buds - using sharp, CLEAN secateurs. Remove the dead, dying and diseased wood by late spring and burn it or dispose of it. (Do not put in your compost!) keeping the shape open to allow a flow of air.

Treat infections with powdered sulphur, which is deemed organically acceptable and will not harm bees.

I also found this information which might be useful if you intend to purchase any more roses....

[Some cultivars are partially resistant to black spot but in a bad year all varieties may succumb. Generally, many of the older cultivars and more yellow than red or pink cultivars are susceptible to the disease. So checking catalogues and choosing resistant varieties, such as 'Bonita', 'Royal William' or 'New Dawn', and growing a mixed planting should help. Rose varieties less than five years old should be relatively disease resistant.]

21 Jul, 2008

 

Good advice Jess.When the black spot spore lands on the leaf, it germinates and sends its little root system through the cell wall into the sap stream below and it proliferates. If you thicken that cell wall, the spore lands on the top, the root system germinates and it goes halfway through and then fizzles out, and so you get less black spot. But how do you thicken that cell wall? It's easy - just use sulphate of potash and give them about 100 to 150 grams per bush about four times a year – this should guarantee a lot less black spot.Even after attending to the nutritional needs of roses, there will still be a need to spray. There are plenty of safe and organic ways to treat black spot. Try using two teaspoons of bicarb soda in 5 litres of water, add a couple of drops of detergent or a couple of drops of seaweed extract. This makes an excellent and inexpensive fungicide. Or use Bordeaux mixture or one of the other copper based fungicides. Thank you, Gardening Australia!
http://www.abc.net.au/gardening/stories/s1885774.htm

22 Jul, 2008

 

For many years I have used ordinary washing up liquid greatly diluted in a spray bottle and gently sprayed the affected areas for greenfly; Black spot ??? not sure if it works for that too;. However this year I am in Portugal and used the same treatment and the roses are now in poor condition; I think the very hot sun has had a reaction to washing up liquid; my advice is to use it sparingly and in the evening when the sun has gone down

25 Jun, 2009

How do I say thanks?

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