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Full Length Research Paper
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Effect of aqueous plant
extracts on tea red spider mite, Oligonychus coffeae,
Nietner (Tetranychidae: Acarina) and Stethorus gilvifrons
Mulsant
M. Sarmah1, A. Rahman1, A. K.
Phukan1, and G. Gurusubramanian2*
1Department
of Entomology, Plant Protection Division, Tocklai
Experimental Station, Tea Research Association, Jorhat- 785
008, Assam, India.
2Department
of Zoology, Mizoram University, Aizawl - 796 009, Mizoram,
India.
*Corresponding author.
E-mail: gurus64@yahoo.com.
Phone: 0389 - 2330724. Fax: 0389 - 2330642/2330644.
Accepted
28 May, 2007 |
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Abstract |
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Four aqueous plant extracts (APEs) of Acorus calamus
(L), Xanthium strumarium (L), Polygonum hydropiper
(L) and Clerodendron infortunatum (Gaertn) were
evaluated under both laboratory and field conditions at 2.5,
5.0 and 10.0% (w/v) concentrations against tea red spider
mite, Oligonychus coffeae (Nietner). Also, the impact
of APEs on survival and feeding of Stethorus gilvifrons,
a potent coccinellid predator of red spider mite was
studied. Parameters assessed were ovicidal activity and
acaricidal activity in case of red spider mite, and feeding
activity and adult mortality for the coccinellid. Strong
ovicidal action was observed with X. strumarium
(87.09%) and A. calamus (70.62%) whereas least action
in P. hydropiper (30.86%) and C. infortunatum
(20.58%). All the APEs showed > 50% mortality of red spider
mite at higher concentrations (5 and 10%) under laboratory
conditions. Field evaluation of APEs recorded 46.9 – 81.8%
mite reduction at 5.0% and 64.7 – 100.0% at 10.0%
concentration. More acaricidal activity was noticed in C.
infortunatum and X. strumarium under field
condition. The APEs, even at higher concentration (10%),
caused no mortality to the adults of S. gilvifrons
for 14 days, and no significant change in feeding after 24 h
in comparison with untreated control. Crude plant extracts
of A. calamus, X. strumarium, P. hydropiper
and C. infortunatum can effectively be utilized as
safer phytopesticidal products in both organic and inorganic
tea estates as one of the potent tools in integrated mite
management.
Key
words:
Tea, Oligonychus coffeae, aqueous plant extracts,
Stethorus gilvifrons. |
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