Plants with Pest Control Properties Against Urban Pests - Urban Insect Pests: Sustainable Management Strategies - page 219

requirements or waivers for products of this
type, particularly for use against public
health pests where food residues are not an
issue (Isman, 2008).

pyrethroid insecticide, and has the potential
to clear a room of insects in around 30 min
and will remain effective for more than 6 h.
Mosquito coils also make use of pyrethrin
or a pyrethroid that when lit will smoulder
at a steady rate. Coils cause mosquito bite
inhibition, repellence, deterrence, knock-
down and death. Inhibition of nuisance
biting is seen in all mosquito species: Aedes ,
Anopheles , Culex and Mansonia (Goodyer
et al ., 2010).

Plant-derived Insecticides

Recent trends show the commercial use of
natural product and natural product-
derived insecticides continues to increase,
whereas sales of organophosphates are
declining (Dayan et al ., 2009). The same
paper quoted that three out of the fi ve most
commonly used insecticide classes are
natural-product or natural-product-derived
ones, i.e. neonicotinoids, pyrethroids and
other natural products, each accounting for
19.5%, 15.7% and 7.6% of the combined
worldwide sales, respectively (Dayan et al .,
2009).
Nicotinoids are similar to and are
modelled on the natural nicotine. They
have been previously referred to as
nitroquanidines, neonicotinyls, neonico-
tinoids, chloronicotines and more recently
as the chloronicotinyls. Nicotinoids include
imidacloprid, thiamethoxam, nitenpyram,
clothianidin and dinotefuran. The nico-
tinoids act on the central nervous system of
insects, leading to irreversible blockage of
postsynaptic nicotinergic acetylcholine
receptors. The neonicotinoids, the newest
major class of insecticides, have outstanding
potency and systemic action for crop
protection against piercing-sucking pests,
and they are highly effective for fl ea control
on cats and dogs. The low affi nity of
neonicotinoids for vertebrate relative to
insect nicotinic receptors is a major factor
in their favourable toxicological profi le
(Tomizawa and Casida, 2005).
Pyrethroids are synthetic materials
designed to imitate natural pyrethrum, but
they are much more toxic and long lasting
(Singh and Srivastava, 1999). Modern
pyrethroids bear little structural resem-
blance to the natural pyrethrins; their
molecular mechanism of action differs as
well (Dubey, 2011). Pyrethroid insecticide
is commonly used as an insecticide
vaporizer, in electrical devices releasing a

Plant Compounds Active Against
Urban Pests

Mosquito

Mosquitoes receive most attention among
urban pests when surveying literature on
natural products with insecticidal prop-
erties. A vast number of both plant extracts
in crude forms and isolated pure compounds
have been shown to act as repellents,
feeding deterrents, in retarding reproduction
and as insect growth regulators against
various mosquito species. There are several
reports, particularly in Africa, describing
the burning of plant materials or hanging
them in homes, both of which are considered
effective in driving away mosquitoes. Such
reports do not prove effi cacy of the product
but are crucial in the pursuit for the active
compounds.
Probably the fi rst documented report on
the use of plants against mosquitoes is the
use of alkaloids including nicotine, ana-
basine, methylanabasine and lupinine from
the Russian weed Anabasis aphylla . These
compounds showed effi cacy against various
species of Culex (Campbell et al. , 1933). A
review of literature by Sukumar et al.
(1991) listed 344 plants species and their
activity against mosquitoes, which in-
cluded repellence, toxicity, and growth and
oviposition deterrence. The repellence
effect of 41 essential oils against Aedes ,
Anopheles and Culex mosquitoes was
reported by Amer and Mehlhorn (2006).
The study found the fi ve most effective
oils were those of litsea ( Litsea cubeba ),
cajeput ( Melaleuca leucadendron ), niaouli