© Benaki Phytopathological Institute
Toxicity of insecticides on
Trichogramma cacoeciae
65
plied to tomato leaves, on
T. cacoeciae
adults
was assessed. The experiment was conduct-
ed on tomato leaves because it is a common
host for lepidopteran insects parasitized
by
T. cacoeciae
. For this purpose, 75 toma-
to seedlings of the local cultivar Alhassawi
were transplanted in five replicate plots,
each measuring 2 x 3 m. Plants were grown
in a mixture of peat moss (75% by vol.), na-
tive fine sand, perlite and vermiculite.
Each insecticide was applied to plants in
four replicate plots, while the control (water)
was applied to the fifth plot. Following treat-
ment with insecticide or water, the plants
were left to dry for three hours. Five toma-
to leaves, measuring 5-6 cm long, were ran-
domly collected from the upper third of the
plant in each plot of each insecticide treat-
ment. Each set of five leaves, representing
one replicate per treatment, was placed in a
separate bag and transferred to the labora-
tory. Leaves were cut into 1 cm
2
pieces and
placed in a test tube (5 x 1.5 cm) along with
20 x one day old adults of
T. cacoeciae
(Suh
et
al
., 2000). The tubes were then sealed with
cotton wool and kept in an incubator for 24
h, before mortality was recorded at 1, 2, 3, 7,
14 days post-treatment. Mortality ratio data
were corrected using the Abbott’s formula
(Abbott, 1925).
Statistical analysis
The experiment was designed as a ran-
domized complete block design using five
replicates per treatment in addition to the
control. Corrected percent mortality was
calculated (Abbott 1925) and data were an-
alyzed using Analysis of Variance (ANOVA).
Separation of the means was conducted us-
ing the Fisher’s protected Least Significant
Difference test (PLSD), (P < 0.05) (Steel
et al.,
1997). The analyses were performed using
SPSS 12.0 Windows (SPSS Inc., 2003).
Results and Discussion
Lethal Effects
Survival and corrected mortality of adult
females of
T. cacoeciae
after 24 h exposure to
dry insecticide residues differed among the
insecticides (Table 2). Cypermethrin, delta-
methrin, malathion, phenthoate, methomyl
and carbosulfan, were moderately harmful
Table 2.
Survival and corrected mortality of adult females of the egg parasitoid
Trichogram-
ma cacoeciae
, when exposed to dry residues of insecticides on glass surfaces treated at the
recommended application rates.
Treatment
Adult survival
Corrected
mortality
(E%)
IOBC Classification
Insecticide
Class
Cypermethrin (Hi power)
Pyrethroid
2.00 ± 0.77 gh
98.00
3
Deltamethrin (Flotron 2.5%)
4.33 ± 0.26 efg
95.67
3
Malathion (Sulmathion 57%)
Organophosphate
1.00 ± 0.45 h
99.00
3
Phenthoate (Peston 50%)
3.33 ± 0.26 fgh
96.67
3
Methomyl (Metho900)
Carbamate
1.00 ± 0.45 h
99.00
3
Carbosulfan (Marshal 25%)
5.00 ± 0.45 ef
95.00
3
Bistrifluron (Hanaro 10%)
IGR
92.67 ± 0.7 b
7.33
1
Pyriproxyfen (Muligan 10%)
40.33 ± 0.68 d
59.76
2
Matrine (Kingbo 0.6%)
Plant Extract
50.00 ± 0.89 c
50.00
2
Azadirachtin (Amen 1.0%)
6.67 ± 1.37 e
93.33
3
Control
100.0 ± 0.00 a
-
LSD ( P > 0.05) = 28.639
F value = 0.041
All values aremeans of 5 replicates ± SE. Means in the same column followed by the same letter are not significantly
different (Fisher’s test, P > 0.05). IOBC insecticide classification, where Class 1: harmless (E < 30%); Class 2: slightly
harmful (30% < E < 79%); Class 3: moderately harmful (80% < E < 99%); and Class 4: harmful (E > 99%).
