International Journal of Agricultural Science and Food Technology Citation: Seenivasan S, Dhanakodi K, Muraleedharan NN (2015) Residues of Propargite in Tea. Int J Agricultural Sci Food Technology 1(1): 012-015. 012 Abstract Propargite is an acaricide extensively used in India for controlling the populations of the red spider mite (RSM) infesting tea. Field experiments were conducted at two places in Tamil Nadu (India) during the dry season to determine the residues of propargite in black tea. Residues were quantiied at different harvest intervals of ‘0’ (3 hr), 1 st , 3 rd , 5 th , 7 th , 10 th and 14 th day after acaricide application. Persistence, dissipation pattern, half-life value and safe harvest interval of the acaricide in tea were calculated. Residues of propargite dissipated exponentially after application at both the locations and reached below the CODEX MRL of 5 mg/kg on the 7 th day. Regression lines drawn on propargite showed that like other acaricides it followed the irst order dissipation kinetics. Half-life values varied from 1.63 to 1.92 days for propargite and a safety harvest interval of 7 days is suggested for the tea crop. Introduction Tea contains an array of chemical constituents, some of which are as unique as the plant itself. he main constituents of tea leaves are carbohydrates, proteins, polyphenols, cafeine, theanine, enzymes, vitamins and minerals. he chemicals in the green tea leaves undergo drastic changes when they are processed into black, green or oolong tea. From the pharmacological and therapeutical points of view polyphenols and cafeine are the most important, though vitamins and minerals are also considered medically signiicant research has indicated that the beneicial efects of tea are due its polyphenolic contents that may afect carcinogen metabolism, free radical scavenging and formation of DNA adducts [1,2]. Such a healthy beverage should also be free from the residues of pesticides and heavy metals. he tea crop is attacked by several pests and diseases and it is imperative that plant protection chemicals are applied to reduce the severity of infestation. Propargite (Omite 57 EC) [2-(p-tert-butylphenoxy)cyclohexyl 2-propynyl sulite] an acaricide with a unique chemical coniguration consisting sulite moiety, has found a place in the list of chemicals recommended for red spider mite control in tea in south India [3]. Propargite is registered with Central Insecticides Board (CIB) in India for usage on tea and cleared under the Prevention of Food adulteration (PFA) Act. A few reports are available on the degradation of certain commonly used pesticides and their residues in tea [4-10]. Similarly research papers have been published on the residues of propargite in tomatoes [11], fruits and vegetables [12] and dissipation behavior of propargite residues in soil, apple and tea [13]. However, there is no published information on the residues of propargite in black tea under the agro climatic conditions of south India. Hence, a study was undertaken to generate data on residues, persistence and dissipation of propargite in tea. Research Article Residues of Propargite in Tea Materials and Methods Field trials and experimental design he experiments were conducted in tea ields at Valparai and Coonoor (Tamil Nadu, India). Plots measuring 100 sq.m, containing tea plants of mixed cultivars with appropriate guard rows, were used for the study. Tea plants had been planted in double hedge, in triangular planting system at a spacing of 0.75 x 0.75 x 1.25 m under the shade tree, Grevillea robusta (6 x 6 m spacing). he treatments were application of propargite 57 EC @ 1000 and 2000 mL/ha and an untreated control. he acaricide was applied with hand operated knapsack sprayer, using a spray volume of 400 L/ha. Tea shoots consisting of three leaves and a bud were harvested on 0 (3 hours), 1 st , 3 rd , 5 th , 7 th , 10 th and 14 th days ater application of the chemical. he shoots harvested on the speciic day ater chemical application were processed in a miniature manufacturing unit. Harvested shoots were spread in a withering trough and allowed to wither with natural air, blown underneath for 16-18 hours. Withered leaves were passed through a rotorvane for crushing and mixing of leaves and juice. his was passed four times through a roller cut CTC (Crush, Tear and Curl) machine. he resulting cut “dhool” was spread over the fermentation trays at a thickness of about 2 cm, maintaining a relative humidity of 90-95% for one hour. Fermented (enzymic oxidation) “dhool” was dried in a mini luid bed drier to attain a inal moisture content of 2.5-3.0%. Black tea samples thus obtained were analysed in a high performance liquid chromatograph (HPLC, Agilent 1100 Series) equipped with diode array detector, following standard procedure. Chemicals and reagents An analytical reference standard of propargite (purity 95.40 %) was procured from Dr. Ehrenstorfer, Germany and the commercial formulation of propargite (Omite 57E) was supplied by the manufacturer, M/s. Chemtura Chemicals Pvt. Limited, Mumbai, India. Hexane, acetone, isopropyl alcohol, sodium chloride and sodium sulphate were obtained from M/s. Merck, Mumbai, India; all were of chromatographic purity. Florisil (60 – 100 mesh, pesticide Subbiah Seenivasan 1 *, Kirubakaran Dhanakodi 2 and Narayanan Nair Muraleedharan 3 1 he Institute of Environmental and Human Health, Texas Tech University, Lubbock – 79415, Texas, USA 2 UPASI Tea Research Foundation, Nirar Dam BPO, Valparai – 642 127, India 3 Tea Research Tea Research Association, Tocklai Experimental Station, Jorhat-78500, Assam, India Dates: Received: 04 September, 2015; Accepted: 12 October, 2015; Published: 14 October, 2015 *Corresponding author: S. Seenivasan, The Institute of Environmental and Human Health, Texas Tech University, Lubbock – 79415, Texas, USA, Tel: +001-806-885-4567; Fax: +001; E-mail: www.peertechz.com Keywords: Propargite; Residues; Tea; Persistence; Dissipation; MRL