New Horizons in Insect Science Towards Sustainable Pest Management

Nanomaterials: A Review of Their Action and Application in Pest Management ... 119

2004 ; Love et al. 2005 ) and colloidal gold is
commonly used to stain proteins in gels or blot-
ted on membranes. The high binding affinity of
noble metal like gold to proteins was attributed
to the affinity of the thiols for the amino groups
(Joshi et al. 2004 ; Love et al. 2005 ; Duchesne
and Fernig 2007 ; Whaley et al. 2000 ; Zhu et al.
2008a, b). It has also been reported that gold
nanoparticles can bind with SH-group contain-
ing amino acids of proteins (Duchesne et al.
2008 ). Gold metal is a conductor of heat, but,
when its size is reduced by 1 billion, it becomes
insulator so that it can be used to deliver the
toxicant to the target cells directly. This unique
property will be of immense value in medical,
entomological, and allied sciences.
Peculiar symptoms of nanoparticles were
larval death and larval tissue lysis. It has been
reported that gold nanoparticles have the abil-
ity to stimulate different physiological enzymes
(Biju 2007 ). DNA-tagged gold nanoparticles can
affect phosphorylation in relation to kinase activ-
ity that helps to inhibit the indirect effect of DNA
functions and thus lysis of the insect–pest tissue
leads to death of the S. litura. DNA-conjugated-
gold nanoparticles have an effect on kinase activ-
ity (Brennan et al. 2006 ; Wang et al. 2006 ; Ehrlich
et al. 2008 ). In this context, DNA-tagged nanop-
olymer has a tremendous potential to locate the
specific damaged part of the tissues in relation to
its application in different physiological process-
es (Stadler et al. 2007 ; Liedl et al. 2010 ). Thus,
DNA-tagged gold nanoparticles may stimulate
the chitinases activity for disruption of the larval
tissue of S. litura from 3rd day onwards.

Effect of Inorganic Nanoparticles CdS,

Nano-Ag, and Nano-TiO2 Against

S. litura

The CdS exhibited negligible larval mortality,

as the days advanced, larval mortality increased

(Table 2 ). On 3rd day after treatment (DAT), the

larval mortality ranged from 4.50 to 13.79 %,

whereas on 9th DAT the cumulative larval mor-

tality was ranged from 21.41 to 93.79 % in 150

and 2400 ppm, respectively. Maximum mortal-

ity (93.79 %) was recorded in 2400 ppm and fol-

lowed by 1200 and 600 ppm (73.79 and 51.72 %,

respectively). In case of other treatments, the

larval mortality was the least (150 and 300 ppm

recorded 24.41 and 38.40 % mortality, respec-

tively). Nano-Ag caused only 56.89 % mortal-

ity at 2400 ppm (Table 2 ) followed by 46.89

and 33.44 % mortality at 1200 and 600 ppm, re-

spectively. Least mortality (22.50 and 15.45 %)

was observed in 300 and 150 ppm. Nano-TiO2

showed very low effect at 3rd and 5th days after

treatment, the mortality ranged from 2.50 to

13.79 % and 7.84 to 33.79 per ppm, respectively.

After 7 days, the mortality further increased and

maximum of 53.79 % larval mortality was re-

corded in 2400 ppm and the lowest was 13.50 %

in 150 ppm. During 9th DAT, resulted 73.79 %

of cumulative larval mortality in 2400 ppm and

the least was 18.50% in 150 ppm. Another pe-

culiar observation recorded was in this treatment

discharge of larval inner contents due to ruptured

midgut during 7th and 9th days after treatment.

The CdS, Nano-Ag, and Nano-TiO2 ceased

active movement larvae, the skin and entire

body became stiff and hard and oozing of the

Treatment PPM Egg Second instar

larvae

Third instar

larvae

Fourth instar

larvae

Adults

5 77.1 56.3 30 45.3 57.6

10 77.2 65 45 54 62.4

20 80.1 66.1 53 54.7 70.8

40 89.2 72.8 56.3 60.3 72.6

80 96.4 74.3 66.3 67.5 89.3

Control 0 0 0 0 0

SEm ± 1.68 0.96 1.63 0.51 0.94

CD@5 % 3.80 2.86 4.85 1.54 2.88

Table 2 Effect of select
concentrations of RH-5992
on eggs, larvae, and adults
of C. cephalonica