Agriculture Reference
In-Depth Information
that baits be deployed early in the feeding
cycle of the colony, preferably late spring
and early summer, to ensure adequate
uptake of bait.
review of plants that have activity against
leaf-cutting ants and some termites.
Numerous preliminary studies indicate that
extracts of plants are toxic, repellent or both
to termites.
Liquidambar orientalis
heart-
wood was deterrent to termite feeding (Terzi
et al.,
2012a). Crude extracts of Indian
medicinal plants such as
Andrographis
lineata
, Mexican poppy,
Argemone mexi-
cana
, and pipe vines,
Aristolochia bracteo-
late
, are toxic to
C. formosanus
(Elango
et
al.,
2012).
The following studies indicate that crude
extracts have biological activity but the
chemical identity of the active ingredients
is unknown. Extracts of the plant
Lantana
camara
(Yuan and Hu, 2012), teakwood
(Dungani
et al
., 2012) and garlic (Saljoqi
et
al.
, 2012), and the essential oils of
Eucalyptus citriodora
kill and repel termites
(Manzoor
et al.,
2012). The essential oils of
eucalyptus (
Eucalyptus globulus
), oregano
(
Origanum vulgare
), cinnamon (
Cinnamo-
mum verum
), thyme (
Thymus vulgaris
),
lemongrass (
Cymbopogon citratus
), clove
(
Syzygium aromaticum
) and rosemary
(
Rosmarinus offi cinalis
) show strong
activity against
Odontotermes assamensis
,
especially some phenolic compounds
(Pandey
et al
., 2012). Extracts of leaves of
Azadirachta indica
kill
C. gestroi
(Inacio
and de Carvalho, 2012). Aqueous extracts of
garlic (
Allium sativum
) are toxic to
Heterotermes indicola
(Saljoqi
et al.
, 2012).
When applied to susceptible woods,
extracts of mimosa and quebracho protect
them from
Reticulitermes grassei
(Tascioglu
et al.
, 2012). The isolation and identifi cation
of these active compounds are necessary
before they can be considered for pest
management programmes.
In other studies preliminary isolations
and identifi cations have been conducted
and the chemical nature of the repellency or
toxicity is better understood. When the
active compound rubrynolide from crude
ethyl acetate extracts from a tropical tree
red louro,
Sextonia rubra
, was applied to
the surface of wood, it was toxic and
deterred
R. fl avipes
feeding. Deposits of
0.95 μg mm
-2
provided 80% kill of termites
in 3 days, which could make it a promising
Alternative methods
The application of dust formulations con-
sisting of Paris green and arsenic to sub-
terranean termite tubes was popular in the
1920s and 1930s (Randall and Doody, 1934).
With the advent of slow-acting insecticides
there has been a resurgence in this direct
treatment approach again. Zhao
et al
. (2012)
showed about 20-30 g of 3% ivermectin
dust could eliminate
C. formosanus
colonies
in 3.5 to 8 months. No termites were found
in monitors for the next year. About 3 g of
ivermectin dust applied to monitoring
stations with
Odontotermes formosanus
and
Macrotermes barneyi
provided signifi -
cant reductions in trees being damaged by
the termites (Jiang
et al
., 2011). Dust
formulations containing 0.5% fi pronil were
readily and effectively transferred to un-
exposed nest mates with donors and
recipients dying within about 20 h (Gautam
et al.
, 2012). Also direct application of
0.3% fi pronil dust to
C. formosanus
workers and mud tubes on the surface of
trees effectively eliminated termites within
1 month (Lin
et al.
, 2011). The habit of
some species such as
C. formosanus
to
attack living trees makes it necessary to
include their treatment in a comprehensive
area-wide IPM programme (Osbrink
et al.,
2011) and dust applications may be the
appropriate solution.
Over the years, numerous natural prod-
ucts and derived compounds have been
tested for biological activity against sub-
terranean termites. One of the most frequent
justifi cations for their use is that these
natural products will be more environ-
mentally friendly than the existing chem-
istries. While the research may reveal new
compounds of economic interest, nothing is
certain about the toxicological safety. Verma
et al.
(2009) lists many of the plants and
natural products that have been tested and
Boulogne
et al.
(2012) provides an excellent
Search WWH ::
Custom Search