Journal of Tea Science Research. 2015, Vol. 5, No. 6, 1-7
6
Table 3 Field performance of some commercial botanical biopesticides against red spider mites infesting tea
Treatment
Dosage
/ha
Pre-treatment
(No. of mites)
% effectiveness of biopesticides after application*
After 1
st
spray
After 2
nd
spray
Overall Mean
1
st
week
2
nd
week
3
rd
week
4
th
week
T
1
- Bio-Cawach 800 ml
38
70.83±1.20e
66.48±1.66e
84.33±0.96e
74.64±1.58e
74.07±1.35d
T
2
- Karanza
1000 ml 36
73.22±1.31d
69.47±1.70c
88.23±1.12d
80.02±1.37c
77.74±1.38c
T
3
-
Miticon
1000 ml 42
78.93±1.64b
70.34±1.28b
92.56±1.26a
83.52±1.66a
81.34±1.46a
T
4
- Neemakar
1000 ml 48
76.85±1.28c
71.44±1.56a
89.32±1.72c
79.88±1.52d
79.37±1.52b
T
5
- Rescue
500 ml
40
79.58±1.72a
72.00±1.44a
91.28±1.80b
81.18±1.46b
81.01±1.61a
T
6
- Torpedo
500 ml
39
68.64±1.54f
67.78±1.38d
83.61±1.42e
79.76±1.14d
74.95±1.37d
Sx
1.410
0.824
0.862
0.365
0.728
Probability level
0.05
0.05
0.05
0.05
0.05
*Mean of three observations ±Standard error of means at a given concentration Within column values followed by different letter(s)
are significantly different by DMRT at p<0.05
Figure 2 Effectiveness of different plant origin biopesticides
against red spider mite in field
Among the tested biopesticides, Miticon showed the
highest toxic effect, whereas
Bio-Cawach showed
lowest toxic effect against the red spider mite in both
laboratory and field conditions. Muraleedharan and
Selvasundaram (1993) found that the two commercial
neem products namely, RD-9 Repelin (ITC) and
Neemgold (SPIC) @ 1000 ml/ha reduced the
incidence the both pink mites and flushworms. Babu
et al
.
(2009) stated that a new herbal product,
Derrimax (derived from
Pongamia glabra
) @ 150
ml/ha reduced the number of red spider mite (84.04%
bio-efficacy) on par with propargite (85.99% bio-efficacy).
Effect of biopesticides on
Stethorus gilvifrons
and
Oxyopes
sp.
Result revealed that no mortality of adult
of
Stethorus
gilvifrons
and
Oxyopes
sp. was found till 14 days after
spraying in all the treatments. Application of the tested
biopesticides did not affect the non-target organisms
such as
S. gilvifrons
and
Oxyopes
sp. Sarmah et al.
(2009) also found no mortality to the adults of
S.
gilvifrons
using the aqueous plant extracts
.
Organoleptic test in respect of quality
Tea samples prepared from biopesticide-treated shoots
was found taint free when subjected to organoleptic
evaluation. Organoleptic test revealed that leaf infusions
of made teas prepared from plant extract-treated
leaves as coppery and liquor strength as strong, scoring
32.20~33.80 with GradeAAon a 50-point scale (Table 4).
Table 4 Tasters’ score of made tea produced from plant extracts treated shoots
Treatment
Leaf infusion
Liquor strength
Tasters’ score*
Grade
Remarks
T
1
- Bio-Cawach
Coppery (7.4)
Strong (7.5)
32.80
AA
No taint
T
2
- Karanza
Coppery (7.6)
Strong (7.3)
33.40
AA
No taint
T
3
-
Miticon
Coppery (7.3)
Strong (7.4)
33.30
AA
No taint
T
4
- Neemakar
Coppery (7.7)
Strong (7.5)
32.60
AA
No taint
T
5
- Rescue
Coppery (7.6)
Strong (7.6)
33.10
AA
No taint
T
6
- Torpedo
Coppery (7.5)
Strong (7.4)
32.90
AA
No taint
*Quality score including Leaf infusion, Liquor colour, Briskness, Strength & Creaming down
