Interesting photos of mites

[Maggi Young]

Janos Agoston, a forumist in Hungary who seldom has time to visit the forum, has made a most interesting post to the Pacific Bulb Society list. I have asked his permission to repeat it here. He has kaindly agreed, thank you, Janos.


From the pbs list:
 'mites'

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Janos wrote:
I made some interesting pictures from mites under microscope, and I think
it is worth of sharing.

Tetranychus urticae - Spidermite



In this picture you can see an adult female with full of eggs (round and
black). This adult exploded because i used the mixture what i use on fungi
when microscopeing :/ Life cycle (from egg to adult) can be 2 days over
30°C till 3-4 weeks at 10°C. As far as i know the fertilized females can
overwinter outside. This mite makes a net, and usually spreads from from
the bottom of the plant to the top. Due to the fast life cycle it is very
hard to keep the population down, and it is known that spider mites can
gain resistancy fast. Likes dry hot weather.


Tarsonemus pallidus - cyclamen mite



This mite is different, from the other one. It lives near the stem tips,
and makes the buds distorted. Never maked a net. The big problem is that
you don't see the mite itself only the distortion, which is not deadly but
also not attractive. Normally florist sulphur is effective agianst this
pest (spray on plants in the evening cause it can burn over 25°C). You have
to check the newly emerging shoots if they are normal.

Janos
Hungary
Z5

[Armin]

Maggi,
thanks for the images. I find annual infestation with Spidermites on my roses (south faced in front of my house).
They are nasty biests

[Jean-Patrick AGIER]

Thanks for these interesting-and stunning-pictures Maggi! The comments are also useful. But are these pests killed by frost? ( -10°C? -20°C?...)
JP

[Maggi Young]

I think that the adults are capable of surviving overwinter in quite low temperatures, JP, but I don't recall having seen a fatal low temperature cited.

[Armin]

Jean-Patrick,
I don't believe deep frost will kill them. There are certainly winter forms or eggs who survive and they have a tremendous fertilisation rate especial in dry and hot conditions (i.e. in front of a south faced wall).

Troublesome is the recognition (if you recognise the leave damages (discoloration due to many small stiches) it is almost too late) and the treatment of infestations as they often develop resistances against usual in the trade pesticides.
I found a pre-treatment of my roses with rape oil solution better then with pesticides. It aglutinates and smothers the little biests. But it is not recommended to spray during sunshine. Oil can burn the leaves.
One can shower the plants with water proactively but it needs to be done regularly but carries the risk of mycotic infections.
I've not found the silver bullet

[Jean-Patrick AGIER]

Hello,
Does anybody know of what I would call "black" soap? This was used decades ago to clean quite everything in the house. This is a kind of "paste" which can be diluted. I've used it against aphids and ants with some success. Could it be efficient on spider mites? I've also tested a dilution on orchids infected by mealy bugs  ( but-to me- a plant infected by these pests isn't curable...). Mealy bugs always reappear...
JP

[ronm]

Is this possibly what my main hero, the great Harry Dodson would use as a spray, 'soft soap'. It was I believe a coal tar product and had to be emulsified well before use? I maybe well of the mark with respect to the  chemical. But he was definately a great grower.