Field efficacy of a biopesticide prepared from Clerodendrum viscosum Vent. (Verbenaceae) against two major tea pests in the sub Himalayan tea plantation of North Bengal, India

International Journal of Acarology

Mukhopadhyay

2012

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Aqueous seed extract of Melia azedarach (L.) was evaluated against tea red spider mite, Oligonychus coffeae (Nietner), in relation to mortality of adult mites, viability of eggs and subsequent adult emergence and oviposition deterrence in the laboratory, and the extract underwent field evaluation in terms of per cent reduction of the mite population. Direct spray methods were used in the laboratory with concentrations of 1%, 2%, 4%, 6%, 8% and 10%. Mortality of O. coffeae was dependent on both concentration and time (56.4% mortality on the first day; 95.6% mortality by the seventh day). The viability of eggs was reduced significantly compared with untreated mite's eggs. Significant reduction in adult emergence and increased duration of total developmental period were noted. Deposition of eggs by adult mites on treated leaf surface was decreased significantly compared with the control. No phytotoxic effect (score 0-5% and grade 1) was observed in the field when tea bushes were sprayed with different doses of aqueous seed extract of M. azedarach. The made tea samples were taint free. An organoleptic test scored both leaf infusions and liquor strength as good, scoring 6.5-7.0 on a 10-point scale. The availability and distribution of this plant (M. azedarach) in and around the tea-growing areas of the sub-Himalayan region, along with its processing for economic utility and inclusion in the current integrated pest management program, is discussed.

mentioning

confidence: 99%

Bioefficacy assessment ofMelia azedarach(L.) seed extract on tea red spider mite,Oligonychus coffeae(Nietner) (Acari: Tetranychidae)

International Journal of Acarology

Mukhopadhyay

2012

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“…The plants were collected from their natural habitats in and around the tea growing belts of north-east India (26.52°-26.14°N, 88.73°-91.77°E). Aqueous extracts were prepared according to the methods described by Roy, Mukhopadhyay, and Gurusubramanian (2010). The plant material was dried in shade for 20 days and powdered, using an electric grinder and passed through a 20-mm-mesh sieve.…”

Section: Collection Of Wild Plants and Preparation Of Aqueous Plant Ementioning

confidence: 99%

Toxicological and physiological activities of some tropical plant extracts againstHyposidra talaca(Walker) (Lepidoptera: Geometridae): an emerging major pest of tea

Rahman

Handique

et al. 2015

Zoology and Ecology

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Studies were undertaken to establish the effectiveness of different concentrations of water extracts of some tropical noneconomic plants viz. Polygonum hydropiper L. (Polygonaceae), Annona squamosa L. (Annonaceae), Clerodendrum viscosum Vent. (Verbenaceae), Argyreia speciosa L. (Convolvulaceae) and Leucas aspera (Willd.) L. (Lamiaceae) in controlling the black inch looper, Hyposidra talaca emerging as a major pest of tea. Bioassays were performed employing the leaf dip method to evaluate the dose-mortality and time-mortality response of 3rd instar larvae of H. talaca to extracts of these plants. Significant variations were observed in lethal concentration and lethal time values. The order of toxicity based on LC 50 values was as follows: P. hydropiper > A. squamosa > C. viscosum > A. speciosa > L. aspera. The lowest LT 50 values at 2% concentration were recorded in A. squamosa (59.11 h) and the highest in L. aspera (83.47 h), while at 4% concentration, LC 50 values were found to be the lowest in P. hydropiper (44.74 h) and the highest in L. aspera (66.06 h). Food consumption by the third instar caterpillar of H. talaca decreased significantly at all concentrations of these plant extracts. No weight gain was observed in all treatments with plant extracts when compared with the control. The values of consumption index, growth rate, efficiency of conversion of ingested food and efficiency of conversion of digested food showed a decreasing trend, while approximate digestibility showed an increasing trend in comparison with the untreated control. Tirtas kai kurių laukinių tropikuose augančių augalų (Polygonum hydropiper L. (Polygonaceae), Annona squamosa L. (Annonaceae), Clerodendrum viscosum Vent. (Verbenaceae), Argyreia speciosa L. (Convolvulaceae) ir Leucas aspera (Willd.) L. (Lamiaceae)) įvairių koncentracijų vandeninių ekstraktų efektyvumas naikinant vieną iš pagrindinių arbatmedžių kenkėjų, Hyposidra talaca. Ekstraktuose mirkant vikšrų maitinimui skirtus arbatmedžio lapus, buvo tiriamos ekstraktų letalinės dozės ir letalaus poveikio pasireiškimo trukmė trečios stadijos H. talaca lervoms. Ekstraktų poveikis ir jo pasireiškimo trukmė reikšmingai skyrėsi. Pagal LC 50 reikšmes nustatytas toksiškumo mažėjimas: P. hydropiper > A. squamosa > C. viscosum > A. speciosa > L. aspera. Naudojant 2% koncentracijos ekstraktus, mažiausia LT 50 (59,11 val.) buvo veikiant arbatmedžio lapus A. squamosa, didžiausia (83,47 val.) -L. aspera ekstraktu. Naudojant 4% koncentracijos ekstraktus, mažiausia LT 50 (44,74 val.) buvo veikiant arbatmedžio lapus P. hydropiper, didžiausia (66,06 val.) -L. aspera ekstraktu. Maitinant H. talaca vikšrus įvairių koncentracijų augaliniuose ekstraktuose pamirkytais arbatmedžio lapais, suvartoto maisto kiekis ženkliai sumažėjo, vikšrų svoris, lyginant su kontroline grupe, nepadidėjo. Maisto suvartojimo rodiklis, vikšrų augimo greitis, praryto maisto įsisavinimo (pavertimo kūno mase) efektyvumas ir metabolizmo efektyvumas mažėjo, maisto virškinimo efektyvumas didėjo.

“…Infestation of red spider mite varied from plot to plot. Hence, after selection of the plots, a pretreatment count was taken in the respective plots and two rounds of foliar spray were applied at 15-day intervals with a hand-operated calibrated knapsack sprayer (hollow cone NMD (Das 1960;Roy et al 2010b). Mean population reduction of mites per treatment was calculated using the following formula: mite population reduction = [(pretreatment population count -post-treatment population count)/pretreatment population count] × 100.…”

Section: Effect Of Aqueous Extract Of the Dry Pericarp Of The Fruits mentioning

confidence: 99%

Terminalia chebulaRetz. (Combretaceae): source of a botanical acaricide againstOligonychus coffeaeNietner (Acarina: Tetranychidae)

International Journal of Acarology

Rahman

Phukan

et al. 2014

Self Cite

Aqueous extract of the dry pericarp of the fruits of Terminalia chebula was evaluated in the laboratory against the tea red spider mite, Oligonychus coffeae (Nietner) to determine its effect on mortality of adult mites, viability of eggs and oviposition deterrence. The same extract was also evaluated in the field to determine its effect on mite populations. A direct spray method was used in the laboratory at concentrations of 1%, 2%, 3%, 4%, 5%, and 6%. Mortality of O. coffeae was dependent on both concentration and time after application. Deposition of eggs by adult mites on treated leaf surfaces decreased significantly and the viability of eggs was also significantly reduced. No phytotoxic effect was observed when tea bushes were sprayed with different doses of aqueous extract of the dry pericarp of the fruits of Terminalia chebula. Tea samples were taint free. Quality (appearance of liquor, flavour, taint, and taste) of tea was not adversely affected by treatment with the extract. With the easy availability and distribution of T. chebula in and around the tea-growing areas of north east India, along with its processing for economic utilization, it may be incorporated in current integrated pest management programmes of tea.