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South Australia - 18th November 2002
I’m on the mat in Annie’s rose
garden, because her roses have powdery mildew at present. Gee most roses in this
area will have it after the weather we’ve had lately. It makes the leaves and
flower buds contorted and if you look closely the new leaves have a fine white
powdered that later goes black. The worst part is that it makes a mess of your
flowers as they open. Caused by high humidity or poor air circulation often
caused by keen gardeners who try to plant their roses too closely together!
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Control, is a regular event, I’d venture to say a fortnightly vigil for a month or two at this time of year. If you feel a spray is warranted, then use wettable sulphur if the weather is mild (i.e. below 22°C) or it will burn the tender young leaves! If you use Triforine that also controls this mildew and the Downy mildew, which sulphur does not. Downy mildew comes later in the year usually and it’s the copper based compounds that control that on roses and vines. You could of course select resistant rose cultivars! Drop me a line at Messenger Press and I’ll assemble a list of the most reader recommended mildew resistant roses. Keep removing the spent heads on roses as they finish blooming. If left on the bush they attract fungal disease at present, such as botrytis or grey mould, which in itself is not a real drama, but that in turn attracts Western Flower Thrips (WFT) and that is a major pest in some of our commercial flower growing areas at present. The ubiquitous Glory Vine is growing like crazy on the pergolas of the district and all of them need a prune now to make them somewhat manageable. Just remove the long canes and they will make shorter laterals, that still provide shade and an autumn effect. Even grape vines can be lightly pruned for shape too, but make sure you don’t cut back so hard you remove the flowering bunches and leave a few leaves for fruit cover. My yellow sticky traps have started to get the first wave of White flies, so look out. You can of course spray Confidor or use my environmentally safe sticky traps. Check them out at www.greenfingers.com.au or drop me a note care of Messenger Press if you’re not Internet connected. I’ve noticed some of the leafy vegetables in my garden wilting on the odd warm day recently. It’s certainly not lack of water and on close inspection I shaded them from the sun to see an instant recovery. They have grown so soft with all the rain lately that a few warmer days and they are sagging. So the message is… do nothing! I was repotting some plants recently and surprised to see a poorly performing Marguerite daisy had soil borne mealy bugs where the root zone met the terra cotta pot. It also had masses of ant cavities. Message is it’s a good time to inspect potted plants. Just tap them out and if they look OK, simply replace them. If matted, cut some of the roots away and re-pot with fresh potting media. This is not recommended for citrus! As for the ants all I did was roughen up their cavities and that sent them scarpering. They get in their in the first place because of poor water infiltration into the pots. Some pine bark potting media dry out and are very difficult to rewet, short of using a wetting agent and it’s only by a physical inspection of the root zone that you will probably detect that! Repotting is the activity of the month at present. Target all your potted plants for at least an inspection. Tap them out and make sure no ants are resident in cavities. They get there if your potting media is repelling water and many do! Root bound plants need a slice to remove the old matted roots and fresh potting media added. This is not recommended for citrus! Even indoor plants and those at the office, need repotting now. When was the last time your had the office plants repotted? When repotting indoor plants leave them outside on the shaded side of your house for a week afterwards, so clear our any parasites such as mealy bugs and scale. Spray with PestOil or Bug Oil and add a controlled release fertilizer, then stand back. At the office do this dirty work in the toilet block, as it sure beats lugging them down the lift to a car park. Having considered the options, it makes office plant maintenance crews seem worthwhile, eh? Some wholesale nurseries will not allow buyers into their production areas if they have visited another nursery within the previous 2 hours, because the tiny Western Flower Thrips can stay on their clothes and infect ‘clean areas’ very rapidly. Control is a lot more difficult than for other insects we are familiar with, so the simple message is remove or deadhead all your flowers and place them into your wheelie bin with a lid or compost with heat, immediately. |
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