pupae/larvae. An alternative option is to wait 10 more days and then
count the empty pupae with circular emergence hole and dead
pupae.Coordinators: E. Chiel and S. Steinberg (provisional test).
Hypoaspis miles Berlese (Acarina: Laelapidae) Provisional test
Test conditions
Temperature: 20°C ± 1°C
RH: 70 ± 5%
Quality control criteria
Quantity The number of live predators as specified on the label (including lar-
vae, nymphs and adults, excluding eggs). The test should be done
batchwise, just before delivery.
Sex ratio 50% of the adults present should be female. Sex ratio is said to be
significantly influenced by the type of food supplied to the female
mite and/or the density of mites at the mass rearing. Sex ratio is nor-
mally female biased (0.66–0.85)
Fecundity Test is in development.
Description of testing methods
Quantity H. milesis normally propagated and sold in a mixture of sphagnum
and vermiculite. The mites appear as adult individuals as well as in
the larval and the nymph stages and in a mixture with mould mites
(Tyrophagus putrescentiae), which forms the feeding material.
Alternatively, nematodes can be used as food.
The small ‘Berlese technique’ is used when counting the mites (see
description under Neoseiulus cucumeris). First of all, a homogenized
and representative sample is taken. The bottle should be kept at
room temperature (18–25°C) for at least half an hour, because the
mites have to be active enough to let themselves fall through the
sieve. The number and the size of the sample(s) will influence the
precision of the counting. A sample-size of 1 g (c. 5–6 ml) will nor-
mally result in a good count. Put the sample in a metal sieve, 6 cm
diameter, height 2.5 cm, mesh size 450 m and 48% open. The mater-
ial must be spread evenly on the sieve. The sieve is then placed
under a lamp of 150 W at a distance of 6 cm. To ensure that all mites
are driven out and not burnt off, the heating must be started with a
warming up time of 4 min. After 4 min the lamp is turned up to full
power for about 17 min. Under the sieve the falling mites are caught
on white tape with substantial adhesiveness. The number of mites
can be counted directly on this tape. Note that, with a humidity of
the material of c. 45–55%, this method works; whenever the humidity
is higher it does not work any more and a new lamp–sieve distance
and heating time will have to be determined.
Based on the numbers counted, a confidence interval can be calcu-
lated (i.e. it can be estimated within a certain confidence level – e.g.
95% – that the numbers of mites are caught inside a specific calcu-
lated interval). If, for example, a test is made on a 95% confidence
interval and the lower value of the confidence interval is specified on
Quality Control Guidelines for Biocontrol Agents 289