Laboratory evaluation of chlorpyrifos, bifenthrin, imidacloprid ...

Pak. Entomol. Vol. 28, No.2, 2006
Table 3. LT 50 values (hrs) of different concentrations of flufenoxuron 10 DC for M. obesi in treated
soil and in direct exposure
Soil
Concentrations Faisalabad Chakwal Layyah
C 1 (1000 ppm) 2.51 3.62 2.85 1.32
C 2 (500 ppm) 3.23 5.10 3.48 1.80
C 3 (250 ppm) 4.73 7.26 4.45 2.37
C 4 (125 ppm) 7 11 6.37 3.60
C 5 (Control) 98 133 132 132
Direct exposure
DISCUSSION
Chlorpyrifos 40 EC at 1000 ppm was found to be the
most effective insecticide against M. obesi with LT 50
ranging between 9 to 15 min in all the soils. The
LT 50 increases with the decrease in concentration.
Our results are in confirmation with the results of Su
et al. (1987) who stated that mortality of termites
exposed to chlorpyrifos 40 EC typically occurred
within the first 24h of exposure. No penetration was
observed in all the concentrations of chlorpyrifos 40
EC. Su et al. (1995) reported that the termite species
did not penetrate sand containing more > 100ppm of
chlorpyrifos 40 EC. Su and Scheffrahn (1990)
reported that termite did not fully penetrate the
treated sand at high concentration due to high
mortality. Bifenthrin 10EC was not penetrated by
Reticulitermes flavipes at any thickness through the
sand treated with 1ppm (Hu, 2005). Imidcloprid
50SL and thiamethoxam 70WS caused the mortality
in M. obesi but their efficacy did not match with
chlorpyrifos 40 EC and bifenthrin 10EC.
Imidachloprid 50SL was more efficient than
thiamethoxam 70WP and flufenoxuron 10DC. These
results are in agreement to that of Almeida and
Alves (1999) who reported that imidacloprid had
better efficacy against termites. However, Remmen
and Su (2005) reported that actara 70WS was found
to be more toxic against C. formosanus and
Reticulitermes flavipes. Cascade 10DC was found to
be least effective for the control of termites,
nevertheless, at high concentration no penetration
was observed but at lower concentration the termite
species penetrated into the soil.
Topical application of the insecticides on the
termites showed the following order of efficacy:
chlorpyrifos > bifenthrin > flufenoxuron >
thiamethoxam > imidacloprid.
In nutshell, it is nearly difficult to achieve a
homogenous concentration of these insecticides in
the soil. It is unknown how these treatments may
affect field population of termites. Future
investigations include field studies to determine
application of the insecticides per volume basis of
the soil.
REFERENCES
Ahmed, S., A. Naseer and S. Fiaz, 2005a.
Comparative efficacy of botanicals and
insecticides on termites in sugarcane at
Faisalabad. Pak. Entomol., 27 (1): 23-26.
Ahmed , S., M.A. Riaz and A. Hussain, 2005b.
Comparative efficacy of Datura alba nees,
Calotropis procera and imidacloprid on
termites in sugarcane at Faisalabad. Pak.
Entomol., 27 (2): 11-14.
Akhtar, M.S. and A.S. Shahid, 1993. Termites as
pest of agricultural crops in Pakistan. Pak. J.
Zool., 25 (3): 187-193.
Almeida, J.M. and S.B. Alves. 1999. Control of the
subterranean termites Heterotermes tenuis
(Hagen) (Isoptera: Rhinotermitidae) in
sugarcane with termitrap ® baits associated
with Beauveria bassiana (Bals) and
insecticides in dry conditions. Arquivos-do-
Instituto-siologico-sao-Pavlo, 66 (2): 85-90.
Anonymous, 2001a. HDRA the organic
organization: Ryton organic gardens
Coventry CV8, 3LG, UK.
Anonymous, 2001b. Chemical control of
Microtermes obesi and Odontotermes
obesus (termites) in sugarcane. Ann. Rept.
Ayub Agric. Res. Instt. Faisalabad, Pakistan.
pp.39-40.
48