Recent research by Dr Minshad Ansari from Swansea University’s Biocontrol and Natural Products Group has focussed on Crane fly larvae (Tipula paludosa), which causes significant damage to both crops and trees.

The larvae, known as ‘leatherjackets’ cause damage to grass pastures and crops, including cereals, brassicas and lettuce, and also harm tree saplings in forest nurseries. The larvae are currently controlled using chemical insecticides.

However, new EU legislation¹ regarding plant protection products, ask that farmers use environmentally-sensitive, integrated pest management programmes, which use non-chemical methods of pest control where possible.

 Healthy crane fly larva

Professor Tariq Butt who led the research group said: “Now the research team has found that certain strains of fungi can potentially control crane fly infestations, and help reduce the use of chemical insecticides and enabling more environmentally-friendly strategies for pest control. Many chemical pesticides are now being phased out because of their impact on wider ecosystems, so this development couldn't come at a better time."

Laboratory and greenhouse tests over a four week and eight week period, examined how effectivedifferent strains of fungi, a chlorpyrifos-based chemical insecticide and nematode worms (Heterorhabditis bacteriophora) were in controlling crane flies larvae.

Dr Ansari said: “Although our tests showed the chemical insecticide treatment was 100% effective after four weeks, we also found that a particular strain of fungus was equally effective.

“The results looked at 17 strains of ‘entomopathogenic’ fungi, which are fungi that prey on the crane fly larvae, and found that their effects on the different developmental stages of the crane fly, ranged from no-effect to highly damaging.

“Researchers found that strain V1005 of the fungus Metarhizium robertsii (formally known as Metarhizium anisopliae) which had been originally isolated from naturally infected crane fly larvae was the most effective, causing 100% larvae mortality in the four weeks after application.”  

The research team also found that nematode worm caused up to 60% mortality to all developmental stages of the crane fly after an eight week period which led researchers to suggest that the pest control effectiveness of the nematode could be improved if they are combined with a fungal treatment.

 It could also be possible that even a moderately strong strain of fungus may significantly control the crane fly, and possibly other pests, including the June beetle and black vine weevil.

Dr Ansari said: “The results of this study indicate that some fungi particularly the Metarhizium robertsii strain V1005, have the potential for the chemical-free control of this pest and we now look forward to analysing results that our research in field conditions will yield in the hope that we can confirm that fungus is an effective method of bio-control.”

Infected crane fly larvae

This research has now been published in Science for Environment Policy: European Commission DG Environment News Alert Service and full findings of the research are reported in: Ansari, M.A. and T.M. Butt (2012). Evaluation of entomopathogenic fungi and a nematode against the soil-dwelling stages of the crane fly Tipula paludosa. Pest Management Science 68: 1337-1344. DOI: 10.1002/ps.3338.

¹See:http://europa.eu/legislation_summaries/food_safety/plant_health_checks/sa0016_en.htm