B) Economic potential of the predatory mite Hypoaspis
miles to
suppress
Sciaridae
in mushroom cultures
B1) Dose response of H. miles
to
suppress Sciaridae
Method:
Containers of 2 litre volume with 300g of spawned compost exposed to adult Sciaridae
to lay eggs.
Treatments:
- Predatory
mites at several
doses
- Diflubenzuron (Dimilin) at a commercial rate (1g AI/m2)
- Untreated
control
- Catch emerging flies with sticky cards on the lids of the container.
Results:
At approximately 400 adult mites / m2, H. miles provides similar sciarid suppression as diflubenzuron
treatment.
B2) Preliminary comparison of mites, nematodes
and insecticides in
an Irish bag
system
Method:
Experiment conducted with a crop grown in 20 kg compost bags.
Mites were applied
in a “non-commercial” manner (individual mites counted out from mite culture substrate).
Treatments
applied:
- Untreated control
- Insecticide
check (diazinon
granules at 25mg AI/kg compost, diflubenzuron at 1g AI/m2 drench into casing
- 710
H. miles/m2 applied at begin spawn run
- 710 H. miles/m2 applied at begin case
run
- 3 x 106 S. feltiae/m2 applied at begin spawn run
- 3
x 106 S. feltiae/m2 applied at begin case run
Results:
H. miles (710 mites/m2) applied at beginning of spawn run, suppresses
L.
ingenua until mid-case run.
Later application of
H. miles exhibited no effect.
S. feltia (3x106/m2),
applied at beginning of spawn
run had no effect. However, when applied at the beginning of case run,
L. ingenua
suppression was evident
until the the 3rd flush.
Neither
H. miles nor
S. feltiae exhibited Any negative effects
on mushroom yield.
Conclusion:
At present costs, and with a dose response function established under laboratory
conditions, predatory mites (H. miles) and insecticides may provide a similar
cost-benefit ratio in
suppressing Sciaridae.
Sciarid suppression by H. miles
in a mushroom crop (Irish
bag system) has been demonstrated. When H. miles was applied without its carrier
material (vermiculite,
peat, and prey) no negative effect on the crop yield was noticed.
