Bionema says beneficial nematodes could help control agapanthus gall midge

The agapanthus gall midge causes serious economic damage to 400,000 container plants and 1.25 million cut flowers in the UK, according to Bionema.

Gall midge pupae killed with beneficial nematode Steinernema species

Severe midge infestation in flower heads has been seen to cause up to 70% crop loss, as reported by current AHDB-funded research (HNS PO 199). If control methods employed by growers do not work the plants cannot be sold until the following year.

Recent research carried out at Bionema, a Swansea University spin-out company, shows that susceptible stages of midge could be controlled using beneficial nematode, the company says.

Researchers at Bionema conducted studies to assess the use of commercially available entomopathogenic nematodes, as either soil or foliar applications, against midge larvae and pupae.

The nematodes used were members of the genus’ Heterohabditis and Steinernema. In the tests conducted for research purposes, the nematodes were sprayed directly on the flower heads infected with gall midge larvae and pupae.

Managing director Dr Minsahad Ansari said: “The best place to tackle the gall midge larvae and pupae is at source, which is on the flower head or at ground which is where the pupae reside. If there is adequate moisture on the foliage or in the soil, the nematodes can live for 6 to 10 weeks or more. We also spray the nematodes over the flower heads, it is important to keep the flowers damp for at least 2-4 hours which is enough time for nematode to locate and infect the pupae.”

Results showed the nematode Steinernema species infected only the pupal stage of the gall midge and reduced the numbers of emerging adult gall midges.  Gall midge larvae were not susceptible to any of the nematode species tested.

Ansari added: “This research has not resolved the problem of gall midge infestation in Agapanthus, but we have found a method of population control from the results of tests carried out, by targeting the pupal stage.

He says by following the application methods as developed by Bionema for the application of nematodes and incorporating this process into a specifically developed Integrated Pest Management programme, the process will reduce gall midge population in containerised plants and cut flowers under glasshouse production.

Bionema has developed NemaTrident – Tri-Component Nematode System for enhanced insect pest control. The NemaTrident system provides soil or growing media penetration.