Posts

powdery mildew

powdery-mildew

powdery mildew

I noticed this white almost chalk like residue on my corkscew hazel the other day.

It is powdery mildew.

Caused by a variety of fungi  including Oidium, Uncinula & Sphaerotheca; the powdery chalk like residue sits on and clings to the top of the leaf.

It’s sister downey mildew clings to the underside of the leaf and is damp and fluffy to feel… So as not to confuse the 2, remember: powders could not sit on an underside [as simple as that sounds – to the non horticultural C.S.I. diagnostics team it is very important 😉 ].

Back to it…. One must remember that this is a fungal problem. And spores are spread by wind, rain or even plants rubbing together. Powdery mildew likes a dry site and fungi usually grow in areas where it has little chance of being disturbed. So, whilst it can be sprayed/ treated chemically… this will solve the immediate problem but, the chances are the disease will return as the conditions/ environment have not changed. My methodology is to remove all of the diseased material; then wait if possible ’til the off season and move the plant to less enclosed spot.

The reality is, one should also remember that this is not a bacterial disease of the plant so whilst photosynthesis is affected; and therefore fruit/ seed production – the disease is not as such detrimental to the plant.

Chemcal treatment is usually done via the use of a translocated/ systemic insecticide and fungicide mixed as most insects are disease vectors. Make sure [please] you have a seperate applicated sprayer to the one used for herbicide 😉 That said, I prefer working with nature where possible and would always first recommend the biological control first.

While I’m here… if you are spraying it can leave a white residue…. don’t confuse the two 🙂

Reblog this post [with Zemanta]

A Fruit Tree Problem Shared is a Problem…

I have about 20 apple trees in my garden some in groups. Some seperate. One of them was looking particularly bad. I took a closer look….

There are two things that I spot immediately….

fruit-trees-pest and disease

....?

The scaring [left] can often be confused with the marks of apple sawfly…

….but these markings are actually a result of irregular water supply.

The fruit is quite small/ smaller than the fruits on other trees of same variety and some are out of shape.

The sudden availability of water causes the skins to crack.

This coincides with the time they where planted, the fact that they were containerised before and also that no mulching of any format was used.

The second is the wasps….

fruit-trees-pests ireland wasps

...?

the wasps…. [vespula spp.] are attracted to the fruits primarly damaged by birds… talk about lazy 😉

The suggested control by some is to find the wasps nest and destroy it.

I just can’t do that. Or you can cover the trusses with nylon/ muslin bags over the fruit before damage begins [?!] As long as its not in the house. There is nothing wrong with the tree. It’s simply the fruit that is gone from it for this year. What I will do it wait until autumn/ winterwhen all the fruit and leaves and wasps are gone and move the tree to a better spot.

A fruit tree problem shared is a problem solved….;) for next year!

Reblog this post [with Zemanta]