The real blight on allotments this last growing season has been theft.
The site I'm a holder on has had vast amount of stuff stolen this year, ranging from all the shared wheelbarrows to individual plotholder's equipment - hundreds of pounds worth of stuff. More Infuriating though is the theft of produce. There are experienced plot holders who have had almost their entire harvest taken (and not by the local wildlife) throughout the season. I'm lucky, my efforts have been pretty poor this year so my plot hasn't attracted the thieves but for those that spend a vast amount of time and effort, not to mention money, working their plot this is soul destroying.
As for my spuds, they were so bad this year I only wish they could have got far enough to be candidates to spread blight to the commercial growers of dulwich and Forest Hill...