IJH-2018v8n17 - page 7

International Journal of Horticulture, 2018, Vol.8, No.17, 197-203
198
net plot sizes for each treatment were 3.03 x 10.57 m and 3.03 x 7.55 m with seven and five vines, respectively.
The vines were pruned during April and October months every year.
Two insecticidal applications were given at ten days interval in the month of January during both the years with
the help of knapsack sprayer using spray volume of 1,000 litres per hectare. The efficacy of insecticidal treatments
was assessed by recording the number of thrips present on three leaves per plant from five vines in each treatment.
Mean number of thrips per leaf was worked out. These observations were made at one day before first spray as
pre-treatment count and on third, seventh and tenth day after each application as post-treatment counts. The
observations made on tenth day after first spray served as pre-treatment count for the second spray. The per cent
protection against thrips over untreated check was worked out. The per cent reduction in thrips population over
pre-treatment count was also worked out. The fruits from net plots were harvested separately and fruit yield per
vine was computed.
The observations on phytotoxicity symptoms (viz., leaf tip and surface injury, wilting, vein clearing, necrosis,
epinasty and hyponasty) were recorded on first, third, fifth, seventh and tenth day after first and second sprays by
using 0-10 score (Balikai, 2016).
2 Results and Discussion
2.1 First year: Bio-efficacy against thrips,
Scirtothrips dorsalis
Hood and
Thrips palmi
Karny
2.1.1 First spray
A day before insecticidal treatments, the thrips population varied from 9.4 to 10.7 per leaf with non-significant
differences among various treatments.
At three days after first spray, Fipronil 80 WG @ 50 g a.i./ha recorded lowest population of 6.2 thrips per leaf
followed by Fipronil 80 WG @ 40 g a.i./ha (6.4 thrips/leaf) and Fipronil 5 SC @ 40 g a.i./ha (7.2 thrips/leaf) and
were equally effective against thrips. The latter treatment was on par with Spinosad 45 SC @ 84.375 g a.i./ha,
Imidacloprid 200 SL @ 45 g a.i./ha and Standard check (Monocrotophos 36 WSC @ 360 g a.i./ha followed by
Dimethoate 30 EC @ 521 g a.i./ha) with 8.3, 8.5 and 8.6 thrips per leaf, respectively.
At seven days after first insecticidal spray, Fipronil 80 WG @ 50 g a.i./ha recorded lowest population of
4.8 thrips per leaf followed by Fipronil 80 WG @ 40 g a.i./ha (5.1 thrips/leaf) and Fipronil 5 SC @ 40 g
a.i./ha (5.8 thrips/leaf) and remained equally effective against thrips. The latter treatment was on par with
Spinosad 45 SC @ 84.375 g a.i./ha and Imidacloprid 200 SL @ 45 g a.i./ha with 5.8 and 6.5 thrips per leaf
respectively which in turn were on par with Standard check (Monocrotophos 36 WSC @ 360 g a.i./ha followed by
Dimethoate 30 EC @ 521 g a.i./ha). Similar trend continued even at 10 days after first spray (Table 1).
2.1.2 Second spray
At three days after second insecticidal spray, Fipronil 80 WG @ 50 g a.i./ha and 40 g a.i./ha recorded lowest
population of thrips (2.6 and 2.8 thrips/leaf, respectively) indicating their higher and equi-effectiveness. The next
best treatment was Fipronil 5 SC @ 40 g a.i./ha with 3.9 thrips/leaf and was on par with Spinosad 45 SC @
84.375 g a.i./ha and Imidacloprid 200 SL @ 45 g a.i./ha with 4.7 and 4.5 thrips per leaf, respectively. The latter
two treatments were on par with Standard check (Monocrotophos 36 WSC @ 360 g a.i./ha followed by
Dimethoate 30 EC @ 521 g a.i./ha) with 5.5 thrips per leaf.
At seven days after second insecticidal spray, Fipronil 80 WG @ 50 g a.i./ha and 40 g a.i./ha recorded lowest
population of thrips (1.5 and 1.2 thrips/leaf, respectively) indicating their higher and equi-effectiveness. The next
best treatment was Fipronil 5 SC @ 40 g a.i./ha with 2.7 thrips/leaf and was on par with Imidacloprid 200 SL @
45 g a.i./ha with 3.5 thrips per leaf. The latter treatment was on par with Spinosad 45 SC @ 84.375 g a.i./ha and
Standard check (Monocrotophos 36 WSC @ 360 g a.i./ha followed by Dimethoate 30 EC @ 521 g a.i./ha) with
3.8 and 4.0 thrips per leaf, respectively.
At ten days after second spray, Fipronil 80 WG @ 50 g a.i./ha, 40 g a.i./ha and Fipronil 5 SC @ 40 g a.i./ha
recorded lowest population of thrips (0.4, 0.5 and 0.9 thrips/leaf respectively) indicating their higher and equal
1,2,3,4,5,6 8,9,10,11,12,13,14
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