population is expected to grow from 7,6 billion people in 2017 to 9,8 billion
people in 2050 (United Nations, Department of Economic and Social Affairs,
Population Division (2017). World Population Prospects: The 2017 Revision,
custom data acquired via website on 03-01-2018). To be able to sustain this
steep increase in number of people, we need to increase the production of food
as well. To accomplish this feat, a serious increase of efficiency is needed.
Unfortunately, this often involves pesticides, which can have an adverse effect
on biodiversity and ecosystems (CITATION NEEDED). Biological alternatives for
pesticides are available in the form of natural predators, but these come with
Biological Systems has introduced the world to biological pest control by
bringing various products on the market, including Amblyseius swirskii Athias-Henriot, 1962. A. swirskii is a predatory mite that preys on pests such as
whiteflies, trips and several species of herbivorous mites (Messelink et al.,
2005; Bolckmans et al., 2005; Onzo et al., 2012). It is used only in
greenhouses where conditions are managed since this species of predatory mite reproduces
best when temperatures are 25°C (Lee and Gillespie, 2011) and reproduction nearly
stops when temperatures are lower than 15°C (Lee and Gillespie, 2011). One
upside of this species is that it does not enter diapause (Bolckmans et al.,
2005) and thus can be used year-round.
is a method to survive adverse environmental conditions. For mites this
behavior is mostly seen when a mite goes into diapause, it means that it can no
longer control the pest species. Induction of diapause relies on three factors:
photoperiod, the availability of ?-carotenes and temperature (Overmeer and van
Zon, 1983). These three factors can easily be regulated in a controlled setting
such as a greenhouse, but outside of these glassy domes it is a lot more
Netherlands, where average temperatures range from 18-21°C in the warmest months
and daylength quickly shortens to below 14 hours (the critical daylength
according to Van Houten, 1990), this means that a species of mite is needed
that is a lot more cold tolerant than A.
swirskii and does not enter diapause either.
product of Koppert is Limonica, the mite Amblydromalus
limonicus (Garman & McGregor, 1956). This species is a lot more cold
tolerant than A. swirskii, as it can
be active from 13°C and upwards and is also not sensitive to diapause (NEEDS
CITATION). Still, this species is not widely used, because it is not a native
species to Europe (EPPO, 2013).
species that is native to the area is much more favorable as opposed to
introducing a new species. Numerous accounts of species introductions gone awry
are available to us, such as the introduction of the cane toad, Bufo marinus (L., 1758), to Australia in
1935. It was originally introduced as a biocontrol to beetles in the sugar cane
industry. Because the cane toad produce a very potent toxin that acts on the
nervous system and the heart, the decline of many native Australian predators
was linked to the introduction of B.
marinus (‘Commonwealth of Australia’, 2010). As of now, the cane toads
continue to spread at a pace of 40-60 km a year in spite of active control
measures. As a result of
these invasive species, the introduction of new species is heavily regulated in
a lot of countries (Köck, 2015).