[Umbrian]

I am used to my Verbascums being subject to Blackfly infestations and for the leaves to be eaten away by caterpillers but this year I have noticed a very different problem. Noticing one that was just coming into flower was blotched with black patches on the flowering spike I thought it to be the usual blackfly but a closer in spection revealed gummy globules of a shiny substance, a bit like tar. Any ideas on what is causing this anyone?

[David Bracey]

Good question.  It`s either animal. vegetable or mineral.  It`s not mineral.  There is nothing moving or obviously animal therefore it must be vegetable.  A guess is that it is a vascular disease such as soil-borne Verticillium and the large black things are fruiting bodies.  Any other guesses?

[oron peri]

Wondering if it has something to do with the Gymnetron tetrum [Snout Beetle] that you can notice inside each flower.

[Umbrian]

Snout beetles (very aptly named)  are definitely present on this plant and another suffering from the same "gunge" Not far away is another plant in perfect condition, no blackfly, no chewed up leaves and no snout beetles or gunge.
The globules are dispersing now and covering the leaves. Another of those garden mysteries.

[MikeHardman]

Curious...
There is another kingdom to consider - Protista - slime moulds.
http://en.wikipedia.org/wiki/Slime_mold

They come in a wide range of colours. Here's a black one. That is structured, but note that they go through several phases, sometimes appearing somewhat structureless.

Some of them are attracted by specific chemicals (and hence to certain plants) [and repelled by others], as described in this paper, for instance - http://eprints.uwe.ac.uk/14752/.
I have not, in a brief search, found any slime moulds particularly associated with Verbascum.

I am not at all convinced that slime mould is the answer (the arrangement of the black matter seems wrong); it is just another possibility I am throwing into the pot.

[Umbrian]

Very interesting Mike and thanks for your input. Although the shiny appearance of the black slime mould resembles what I have on the Verbascum the form does not although I note that you say they go through different stages. As the substance on the Verbascum is very sticky I would not consider it "slimy" although I do not know the scientific meaning of "slime"! Anyway thanks again for your interest that is what makes this Forum so rewarding for me. Perhaps you could comment on my latest posting about our plague of caterpillers (under Tiiny black caterpillers) - this is proving to be far more worrying.