Mechanisms of Olfaction in Insects - ResearchSpace@Auckland ...
Mechanisms of Olfaction in Insects - ResearchSpace@Auckland ...
Mechanisms of Olfaction in Insects - ResearchSpace@Auckland ...
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General Introduction 23<br />
the attractiveness <strong>of</strong> the lure and the ability <strong>of</strong> the <strong>in</strong>secticide to <strong>in</strong>fect and kill the<br />
<strong>in</strong>sect (Haynes et al., 1986).<br />
One approach to overcome the shortfalls <strong>of</strong> mass trapp<strong>in</strong>g and lure and kill is lure and<br />
<strong>in</strong>fect (Suckl<strong>in</strong>g and Karg, 1999). This has been used on <strong>in</strong>sects such as tobacco<br />
budworm (Jackson et al., 1992), codl<strong>in</strong>g moth (Hrdy et al., 1996) and diamondback<br />
moth (Pell et al., 1993). This approach uses lures such as pheromones comb<strong>in</strong>ed with<br />
<strong>in</strong>sect pathogens such as virus, bacteria or fungi to attract <strong>in</strong>sects to the lure source<br />
(O‟Callaghan and Jackson., 1993). Once <strong>in</strong>fected, the <strong>in</strong>sects act as vectors <strong>of</strong> the<br />
disease and spread it across the population. An advantage <strong>of</strong> us<strong>in</strong>g such an approach<br />
is the speed with which the disease spreads <strong>in</strong> the population and with the <strong>in</strong>sect<br />
themselves act<strong>in</strong>g as vectors for the pathogen, the cont<strong>in</strong>uous need for the lure source<br />
to be ma<strong>in</strong>ta<strong>in</strong>ed and the number <strong>of</strong> lure sources is reduced (Suckl<strong>in</strong>g and Karg,<br />
1999). The downfall <strong>of</strong> this system is that bacterial tox<strong>in</strong>s and viruses are pathogenic<br />
only when consumed hence the lure system has to be designed such that the pathogen<br />
is consumed by the <strong>in</strong>sects. Also, for the pathogen to spread <strong>in</strong> the population, the<br />
<strong>in</strong>fected males have to mate to pass on the pathogen to the females, which must then<br />
be able to spread it to the surface <strong>of</strong> the eggs they lay, which will eventually have to<br />
be consumed by the larvae at eclosion. The success <strong>of</strong> the lure and <strong>in</strong>fect approach<br />
us<strong>in</strong>g bacteria or virus as the pathogen hence largely depend on the efficiency by<br />
which these series <strong>of</strong> events take place. When fungi is used as the pathogen, the lure<br />
has to be presented <strong>in</strong> such a way that it is able to attract the adult <strong>in</strong>sects and keep<br />
them with<strong>in</strong> the vic<strong>in</strong>ity <strong>of</strong> the lure long enough for the fungi to be picked up. The<br />
adult has to be able to spread the fungi to other <strong>in</strong>sects <strong>in</strong> the population before dy<strong>in</strong>g<br />
or upon death; the fungi will grow on the dead <strong>in</strong>sect and spread with<strong>in</strong> the<br />
population. However, the fungi might be susceptible to environmental factors such as<br />
ultra violet (UV) radiation and die, a limit<strong>in</strong>g step to the success <strong>of</strong> this system.<br />
Economic production <strong>of</strong> the pathogen, ma<strong>in</strong>tenance <strong>of</strong> the pathogen <strong>in</strong> the<br />
environment, development <strong>of</strong> an efficient delivery system and ability <strong>of</strong> the pathogen<br />
to spread across the population are factors that have to be taken <strong>in</strong>to consideration<br />
when design<strong>in</strong>g lure and <strong>in</strong>fect control strategies (Suckl<strong>in</strong>g and Karg, 1999).<br />
Other methods <strong>of</strong> reduc<strong>in</strong>g the damage caused to plants are spray<strong>in</strong>g the host plants<br />
with feed<strong>in</strong>g and ovipostion deterrents. Oviposition deterrents will prevent females