The wasp life cycle is a few days longer than the common flies found in poultry
sheds and the female wasp lays one or more eggs (depending on the species) in each
pupa. The wasp is very small and lives at the level of the manure and will go into
a diapause if the weather is cold. As a guide the wasps operate above 15c, however
it is likely in the UK that most deep pits will not drop to very low temperatures
unless the winter is severe. The wasps will also be sensitive to chemicals used
in the house to control flies so that depending on the fly levels a balanced combination
of biological and chemical might be needed.
In a cage house with a high fly population you need to put in place the following
controls:
The amount of wasps required will vary with the challenge. As a guide in a deep
pit house you will need:
- 1 bag of 50,000 wasps / 100 feet of manure
- Initially repeat every 2 weeks for 6 applications
- Reassess at end of the twelve week period before further applications are considered
However, if manure is well managed and adults are also controlled with pheromone
traps and paint on chemicals then this amount can be reduced. It’s all about Manure
management.
Each farm is advised on an individual basis according to the nature of the fly problem.