physicochemical
Contents of 39(1 & 2) 2011 - acharya ng ranga agricultural university
Contents of 39(1 & 2) 2011 - acharya ng ranga agricultural university
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The rice leaf folder population acquired 3.703,<br />
3.386, 0.6035 and 0.6350 fold resistance in kharif season<br />
and 4.249, 3.559, 0.5605 and 0.6630 fold resistance in<br />
rabi season to cartap hydrochloride, fipronil, triazophos<br />
and lambda cyhalothrin respectively at LC90** in<br />
comparison with field recommended concentrations.<br />
The present study clearly exhibited profound<br />
influence of insecticide usage in resistance development.<br />
Less used chemicals recorded low resistance factor.<br />
However, the effectiveness of new molecules was in the<br />
order of lambda cyhalothrin, cartap hydrochloride,<br />
triazophos and fipronil respectively at SD50** level in<br />
both kharif and rabi seasons. While at LD90** level it<br />
was lambda cyhalothrin, fipronil, triazophos and cartap<br />
hydrochloride in kharif season, while in rabi season it<br />
was lambda cyhalothrin, triazophos, fipronil and cartap<br />
hydrochloride. Regarding the conventional insecticides,<br />
the larvae were found resistant to cypermethrin with no<br />
trace of resistance development to chloropyriphos and<br />
endosulfan. M.Sc (Ag), 2008<br />
“Studies on seasonal incidence and Evaluation of different spray schedules<br />
against spotted pod borer, Maruca vitrate (Geyer) (Pyralidace: Lepidoptera)<br />
on blackgram”<br />
Student : Chitti Babu Giddi<br />
Major Advisor : Dr. (Mrs.) T.Madhumathi<br />
Department of Entomology<br />
A field experiment entitled “Studies on seasonal<br />
incidence and evaluation of different spray schedules<br />
against spotted pod borer, Maruca virata (Geyer)<br />
(Pyralidae: Lepidoptera) on blackgram” was conducted<br />
at Agricultural College farm, Bapatla during rabi 2007-<br />
08.<br />
The larval incidence of M. vitrata started during<br />
the third week of December (15.12.2007) i.e.at the early<br />
flowering stage of the crop (30 days after sowing) and<br />
reached a peak level (37 larvae per %0 plants) during<br />
the second week of January (12.01.08) coinciding with<br />
the maximum flowering stage of the crop.<br />
Among the chemical schedules (F1*), the<br />
profenofos schedule (C3*0) was found effective which<br />
recorded the lowest mean number of M. vitrata larvae<br />
(1.24) and damaged flowers/pods (1.61) per five plants.<br />
Among the spray interval schedule (F2*) the four days<br />
interval spray schedule (D1*) was found effective and<br />
has recorded the lowest number of M. vitrata larvae per<br />
five plants (0.80) and mean number of damaged<br />
flowers./pods per five plants (0.93). The interaction<br />
between the profenofos schedule and four days interval<br />
spray schedule i.e. C3D1** was found effective and has<br />
recorded the lowest mean number of M. vitrata larvae<br />
(0.73) and damaged flowers /pods (0.67) per five plants.<br />
The grain yield was highest (2.08 kg per plot)<br />
in the profenofos schedule and in for days interval spray<br />
schedule (2.10 kg per plot) as well as in the interaction<br />
between profenofos and four days interval spray<br />
schedule (C3D1**) i.e. 2.e. 2.40 kg per plot. However,<br />
the CB ratio was highest in neem schedule and ten days<br />
interval schedule (1:208) because of low cost of plant<br />
protection. M.Sc (Ag) ,2008
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