Sunday, May 12, 2013

Latest Doings

Currently, iris larvae are changing skins into their fourth instar, or have just changed.  The weather's invariably vile when they do this... .  Incredibly, they are actually a little ahead of where they were this time last year, though behind on the previous years which brought early springs.

Meanwhile, the Forestry Commission is proposing to aerial spray a small SSSI wood near Pangbourne, Berks, with Bacillus thuringiensis, which kills Lepidoptera larvae, in order to eliminate Oak Processionary Moth.  The wood is reputed to hold Purple Emperor.  Does anyone know this site - Herridge's & Broom Copses near Pangbourne? 

I am unable to express any views as I'm involved with OPM for the NT, and understand the situation. 


irisscientist said...

Not good news Matthew. Considering the mode of action produced by the Bacillus thuringiensis endotoxin, there does not appear that much can really be done. In saying this however, there could still be a chance? Crawford and Harvey (1988) report blockage of the endotoxins action by Calcium (and Barium).

Obviously Barium is out of the question, but following identification of any laying Sallows, spraying relevant bushes with low concentrations of freely available (and cheap) Calcium might well help prevent its toxicity? Just an idea?


BB said...

Have just seen on my local news that the spraying commenced today. On checking the artical on the FC website they state "Non-target caterpillar species present at the time might be affected, but are expected to re-colonise the area from surrounding woodland." however they are not specific about species but I would guess that it would be most? There is also reference to five year study post treatment to monitor the effects. It will be interesting to see?