Development of novel control options for agapanthus gall midge


The agapanthus gall midge, Enigmadiplosis agapanthi poses a risk to both containerised plants and cut flowers. Midge infestation causes flower buds to be deformed and discoloured and often fail to open. Heavy infestations can lead to entire flower heads being aborted. It was first found in the UK in 2014 but has since spread, and has now been found in most counties in southern England and has successfully overwintered in Yorkshire

Due to the relative novelty and lack of information about the midge, there are no current recommendations available for control. Work carried out in HNS PO 199 did not identify any treatments other than cultural methods including removal of infested flower heads, destroying badly infested plants and avoiding growing highly susceptible cultivars such as Northern Star. None of the tested plant protection products had a significant effect when sprayed against larvae in the flowers. A test of drenches against the ground-dwelling stage of the larvae showed a significant effect of thiacloprid (Calypso), EAMU 2014/2153 (due to be withdrawn), but very high mortality in the water controls meant that drenches needed further study.

This project aims to address some crucial gaps in knowledge with the following objectives:

  1. Review cultural control methods used for gall midge pests in a range of crops, identify knowledge gaps and produce a shortlist of candidate control treatments for objectives 3 and 4.
  2. Evaluate the use of sticky traps and water traps for monitoring adult midge emergence.
  3. Complete a field trial testing candidate novel spray treatments against first generation adults on a commercial cut flower farm.
  4. Complete a laboratory pot test of candidate drenches of plant protection products, biological control agents and cultural control methods against the ground dwelling life stages.
Project code:
HNS PO 199a
03 December 2018 - 31 March 2020
AHDB Horticulture
Total project value:
Project leader:
Royal Horticultural Society (research partner RSK ADAS)


HNS PO 199a_GS_ Final report 2020 HNS PO 199a Final report 2020