physicochemical

ABSTRACTS
The pupal period varied from 7-9 days with an
average of 7.8 days. The adult longevity varied from 8-
11 days with an average of 9.8 days. The total life cycle
of pink bollworm varied from 31 to 40 days with an
average of 36.2 days.
Among insecticides tested Spark (deltamethrin
+ triazophos) was the best followed by triazophos,
deltamethrin, thiodicarb and lamda cyhalothrin, while
chlorpyriphos, neem formulation, novaluron and
emamectin benzoate were found ineffective recording
high green boll locule damage and larval incidence in
addition to open boll and open locule damage at harvest.
The highest seed cotton yield was obtained in
Spark (deltamethrin+triazophos) followed by triazophos,
transgenic Bt cotton, deltamethrin, lamda-cyahlothrin and
thiodicarb and the lowest yields were recorded in
emamectin benzoate and novaluron which were on par
with the control. M.Sc (Ag) ,2008
“Studies on relative toxicity of certain insecticides to spotted pod borer,
Maruca vitrata (Geyer) (pyralidae: Lepidotera)”
Student : Manjunath Chouraddi
Major Advisor : Dr. (Mrs.) T. Madhumathi
Department of Entomology
Experiments were conducted in the laboratory
of the Department of Entomology, Agricultural College,
Baatla during Kharif 2007 to find out sensitive method of
bioassay for Maruca vitrata (Geyer) and to study the
relative toxicity of certain commonly used insecticides
viz., chlorpyriphos, prfenofos, endosulfan and carbary1
and newer insecticides viz., indoxacarb, methomy1,
thidicarb, spinosad and emamectin benzoate against
M. vitrata.
The dipping of infested flower of blackgram with
larvae was found to be the sensitive and less labourious
method of bioassay for M. vitrata with LC50** and first at
LC90** in its toxicity against M. vitrata. Order of toxicity
of conventional insecticides at LC50** level was
profenofos > endosulfan> quinalphos> carbary1 and at
lC90** level it was chlorpyriphos > endosulfan >
profenofos > quinalphos > carbary1.
Among the newer insecticides, emamectin
benzoate was first in the order of toxicity at both LC50**
and Lc90** level , shich was 78, 27. 75, 24.5, 22 and
18.25 times more toxic than carbaryl, quinalphos,
chorpyriphos, endosulfan and profenofos at LC50** level
and it was 60.3, 32, 26.4, 23.45 and 17.85 times more
toxic than carbaryl, quinalphos, profenofos, endosulfan
and chlorpyriphos at LC90** ldvel at 72 HAT,
respectively. Methomyl was second in the order of toxicity
at Lc50** level which was found to be 26, 9.25, 8.17,
7.34 and 6.08 times more toxic than carbaryl, quinalphos,
chlorpyriphos, endosulfan and profenofos and third at
LC90** with 11.38, 6.03, 4.98, 4.42 and 3.37 times more
toxic than te above conventional insecticides,
respectively. The order of toxicity of newer insecticides
at LC50** level was emamectin benzoate > methomyl >
indoxacarb > spinosad > thiodicarb and at LC90** level
it was emamectin benxoate > spinosad > methomyl
>indoxacarb > thiodicarb. M.Sc (Ag) ,2008
Insecticide Resistance and its management in rice Leaf folder cnaphalocrocis
medinalis (Guenee) (Pyralidae: Lepidoptera)
Student : S.S.A. Venkateswarao
Major advisor : Dr. P. Raja Sekhar
Department of Entomology
Experiments were conducted in the laboratory
of the Department of Entomology, Agricultural college,
Baptla during Kharif and rabi seasons, 2007-08 to study
the insecticide resistance and its management in rice
leaf folder Cnaphalocrocis medinalis (Guenee)
Pyralidac: Lepidoptera).
The C. medinalis showed 0.8996, 0.596 and
4.7.725 fold resistance in kharif season and 0.864,
0.5497 and 4.109 fold resistance in rabi season to
chlorpfihos, endosulfan and cypermethrin respectively
at LC90** in comparision with field recommended
concentrations.
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