RHS Hemerocallis midge survey

Quality Control

Data quality is good, but coverage pre May 2008 is predominantly limited to Royal Horticultural Society members. Records are verified by Andrew Halstead, Andrew Salisbury, Anna Platoni or Hayley Jones based on samples of damaged flower buds or descriptions and information (primarily host and description of damage) provided in the RHS Advisory Service enquiries or on the on-line form. Grid references are checked against site names. The dataset has been checked using NBN record cleaner

Method steps

1. Records of the Hemerocallis gall midge have been collected via the Royal Horticultural Society Advisory Service (predominantly from RHS members) and from the general public via an on-line recording form on the project website http://www.rhs.org.uk/Science/Plant-pests/Hemerocallis-gall-midge.

The survey aims for UK coverage, however there is bias towards South East England. This may be partially due to the location of a large proportion of Royal Horticultural Society members. The web form aims to reduce this bias. A majority of records after year 2000 are at 1km or better resolution. Many pre year 2000 records only have 10 km resolution.