Abstract |
In a period, which the agriculture is still characterized by the use of pesticides, biological
control has established, in the form of the release of natural enemies. The integrated pest
management is the use of beneficial organisms in combination with chemical control and their
between compatibility is required. The predatory mites of Phytoseiidae family are
commercially available and recently established as biological control agents. Amblyseius
swirskii Athias-Henriot (Acari: Phytoseiidae) is one of the predators used for biological
control of whiteflies and thrips in greenhouse and cover crops, except for the tomato crop on
which it cannot establish. The purpose of this study is to investigate the predator
characterisitcs of Amblyseius swirskii to improve its use as a biological control agent and to
investigate the tomato plant characteristics which affect it.
The resistance of a commercial population and a wild population to two active insecticides,
spinosad and abamectin, was assessed. Then the presence of potential mutations associated
with resistance of abamectin was investigated. Μoreover, we compared the predation rate and
the oviposition rate of the two populations, providing as prey, eggs of Bemisia tabaci.
Furthermore, the genetic diversity of the two populations was studied, using a mitochondrial
marker COI. Additionally, reproductive compatibility between the two populations was
investigated by cross-breeding and the presence of endosymbiotic bacteria Wolbachia,
Rickettsia, Cardinium, Spiroplasma, Hamiltonella, Arsenophonus.
The wild population was detected to be more resistant to the two active substances, compared
to the commercial population. In addition, none of the known mutations in the GluCl gene
sequence were found in the wild population. A higher rate of predation was observed in the
wild population. The mitochondrial marker COI showed low genetic variability in the two
populations. Reproductive compatibility and absence of endosymbiotic bacteria were
identified between the two populations.
An additional purpose of this research is to investigate the installation of A. swirskii predator
on tomato plants. For this reason, the dispersal and the distance that the mite traversed on the
stem of the plant were checked in two commercial varieties of tomato, in the presence and
absence of the beneficial endophytic strain Fusarium Solani - K (FSK). Secondly, the density
of type I, III and type VI hairs was estimated. It was found that the dispersal and the distance
traversed by the mite, is affected by the tomato variety, but not by the beneficial endophytic
strain Fusarium Solani - K (FSK). Moreover, it was found that the density of type VI
glandular hairs differs between the tomato varieties and affects the dispersal of A. swirskii
mite.
In conclusion, to further improve the efficiency of the commercial population Amblyseius
swirskii in terms of resistance and predation rate, it is proposed the genetic enrichment of the
commercial population with wild populations which have desirable characteristics.
Furthermore, tomato varieties can be investigated for the density of their glandular hairs, for
the detection of varieties with favorable characteristics for the phytoseiid predators.
|