The controlled release of insects which feed on Japanese knotweed is being stepped up at locations across south Wales. . . released at six undisclosed sites last month with more over the summer with the aim of establishing a permanent population. Scientists hope the insects, brought from Japan, will stunt the super weed, allowing native species to flourish.
https://www.bbc.co.uk/news/uk-wales-36868449

2016

• Sept 1st 46: All small
• July 11th 27: All small
• June 5th 92: Maybe some quarter of a bag. Started late and was a bit concerned.
  
  Yesterday I had cleared a path along the bund to reach the stand, but didn't see any. Today I realised I had stopped a few metres short as the landscape had changed. A large tree in the bund had fallen into the river taking with it part of the bund. Subsequent tide ingresses and egresses have washed away a substantial part of the bund so I was a bit disorientated.
  This damage is part of a mess in this area which in parts leads to Japanese Knotweed root exposure and spread.

2015

• October 1st 11: Looks like that's it for this year
• August 6th 55: Mostly small, under a foot tall and a few between 1 and 2 foot. Other growth, especially the himalayan balsam, helps by crowding it out hopefully.
• June 17th 32: Small, which means I didn't miss anything significant last pull.
• May 16th 141: Still nothing big only a quarter of a sack
• April 13th 121: Started early given the warm winter and spring but there wasn't very many and they were mostly only a few inches high, a couple about a foot. Seems later in April will be more effective.

2014

• August 22nd 90
• July 4th 128
• May 30th Found 19 mostly missed from last search
• May 26th Pulled 113: RE the damage > some are growing near the drain edge
• April 22nd Started earlier than last year and pulled 333, half a sack when compressed. The site has been damaged through the winter with a number of roots exposed allowing more small shoots

2013

• 20th August Found 119 plants mostly small.
• 17th July Found 95 plants but very small, didn't fill a tenth of a bag.
• 6th July Found 107 plants
• 8th June Surprised to find only 39 plants
• 15th May Started a month later this year due to cold weather. Total count 390 and the largest plant was little more than 2 foot high; down to 1 inch. Filled only half a sack.

2012

• 15th April
  Modified method this time and used a fork to loosen the soil before pulling. Total count 278 and the largest plant was little more than 1 foot high; down to 1 inch.
• 12th May (159)
• 4th June (154)
• 19th June (86)
• 9th August (184) It's been 7 weeks since and it was impossible to get down the bund: I had to go across the lower fields. Although there were a few on the southern end of the patch; all the plants were quite small: what a relief.
• 3rd October Bit concerned about the gap of 8 weeks but all is good. Collected 129 plants, average height 6" that didn't fill one eight of a sack.