The seasonal population of cardamom thrips (Sciothrips cardamomi) and its damage to capsules was assessed on three Cllitivar types (Malabar, Vazhukka and Mysore) of cardamom (Elettaria cardamomum) at Saklespur (Karnataka, India) during 1990-92. Thrips population was high during pre-and post-monsoon periods in all the cultivar types. There were significant differences in thrips damage on the capsules in the three cultivar types. There was no significant correlation between abiotic factors and thrips population. The cultivar type Malabar, mainly grown in Karnataka, recorded about 50% less damage than the other cultivar types. Mean thrips damage on capsules during the three years of study in Malabar, Vazhukka and Mysore cultivam types were 28.44%, 57.92% and 62.55%, respectively.
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SELVAN, JASVIR SINGH, M R SUDHARSHAN, M TAMIL

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Journal of'Spices and Aromatic Crops 8 (1) 19-22 (19.99) Seasonal population of cardamom thrips (Sciothrip.<; cardamomi (Ramk.) on three cultivar types of cardamom (Elettaria cardamomum Maton) JASVIR SINGH', M R SUDHARSHAN & M TAMIL SELVAN India.n Cardarrwln Research Institute Regionul Station, Sahlespur - 573 134, Kamatalw, India. Abstract The seasonal population of cardaIl10m thrips (Sciothrips cardanwmi) and its damage to capsules was assessed on three Cllitivar types (Malabar, Vazhukka and Mysore) of cardamom (Elettaria cardonwllwm) at Saklespur (Karnataka, India) during 1990-92. Thrips population was high during pre-and post-monsoon periods in all the cultivar types. There were significant differences in thrips dan1age on the capsllle<-; in the three cultivar types. There was no significant correlation between abiotic factors and thrips population. The cultivar type Malabar, mainly grown in Karnataka, recorded about 50(J() less damage than the other cultivar types. Mean thrips damage on capsules during the three years of study in Malabar, Vazhukka and Mysore cultivam types were 28.44%, 57.92% and 62.55%, respectively. Key words: cardamom, cultivars, Elettaria cardanwlJllon, _population, Sciothrips cardamomi, thrips. Introduction The cardamom thrips (Sciothrips cardanwm,: (Ramie) (Thysanoptera: Thripidae) is a major, persistent pest of cardamom (Elettaria cardarnomllln Maton) in India. Infestation by thrips affects the quality and quantity of the produce. The affected capsules are mal-formed, shrivelled and may lose their aroma. The three cultivar types (Malabar, Mysore and Vazhukka) show varying degrees of susceptibility to thrips infestation and hence, the present study was carried out to study the seasonal population and damage to capsules by thrips on these three cultivar types. Materials and methods A field trial was laid out in a RED at Indian Cardamom Research Institute Farm at Saklespur (altitude 976 111 lPresent address: Regional Research Station, Spices Board, Tadong, Gangtok . 7?,7 102, Sikkim, India. 20 above MSL, longitude 75 48'38" and latitude 12 56'30") during 1990-92 and thrips population and damage on three cultivar types of cardamom (Malabar, having prostrate panicles; Mysore, with erect panicles and Vazhukka, with seJni-erect panicles) were recorded. There were 12 plants per treatment and 7 replicates. The plants were 7-8 years old. The plots were maintained without pesticide application. The number of larvae and adults of thrips on all the leaf sheaths of five tillers per clump were recorded at monthly intervals for 3 years. Thrips damage on capsules was estimated at different harvests. Tem-perature (mininll11l1 and maximum) and rainfall were also recorded during the study period and correlations between thrips population and these abiotic factors worked out. Results and discussion Thrips population. The population of thrips occurred throughout the year with two peaks, the first peak during pre-1110nSOOn period (February to April) and the second peak during post-monsoon period (September to November) in all the three cultivar types during all the 3 years of study (Fig. 1) supporting the earlier observa-tions of Chakravarthy et al. (1993) and Singh et a.i. (1995 & 1996). Even though Singh et al. there was no significant difference among the cultivar types for thrips population, the cultivar type Malabar harboured relatively less thrips than the other cultivar types as reported earlier by Chandrasekar & Balu (1993). Thrips population did not show signifi_ cant correlation with rain.fall and tem~ perature in all the three cultivar type,. However, the negative correlation with rainfall and number of rainy cloy, indicated that with increase in rainfall) the thrips population decreased, elK reported earlier (K.rishn flInlll'thy et n I., 1989; Chakravarthy et oJ. 1993; Sing-h et ai. 1995). Thrips danwge The differences in thrips damage 011 capsules was significant among the three cultival' types. The average thrips damage on capsules during the :3 years of study in the cnltivar types Malabar, Vazhukka and Mysore was 28.44'/", 57.92% and 62.55%, respectively (Table 1). Thus the cultivar type Malabar, i, about 50% less susceptible to thrill' than the other two cultivar types. The disposition of panicles and capsul,,, and their chemical constituents may hv partly responsible filr the dit1erential thrips damage in the three cultivar types. Table 1. Assessment of damage by thrips on three cultivar types or cardamom Year Cultivar type l'vlcan 1990 1991 1992 Malabar 16.84 41.02 27.45 28.4·1 Vazhukka 32.80 82.50 58.45 G7.92 Mysore 51.25 84.46 51.94 62.5G CD (P ~ 0.051 4.48 4.93 2.59 1.99 CV ((;H 11.44 6.10 4.83 ,1.44 Values indicate thrips infestation in (}(, age "population of cardmnom thrips 2 ~ "-." ~ r ~ ,11 t: w "-." ~ r ~ t: w "-." ~ r 16 14 12 10 8 6 4 2 0 25 20 15 10 5 0 25 20 15 10 5 0 181 Malabar. Vazhukka 0 Mysore I JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Months 1990 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Months 1991 JAN FEB MAR APR MAY JUN JUL' AUG SEP OCT NOV DEC Months 1992 Fig. 1. Seasonal population of thrips in three cultivar types of cardamom 21 22 Acknowledgements Sincere thanks are due to Dr. S N Potty, Director (Research), Spices Board, Ko-chi for his. keen interest and guidance and to Dr. S Varadarasan, Deputy Director (Research), Regional Research Station, Gangtok and Dr. B Gopakumar, Head, Division of Entomology, ICRI, Myladumpara, for their suggestions and for critically examining the manuscript. References Chakravarthy A, Gangappa E & Sh-;'rma A K 1993 Climatic conditions influ-encing insect pests in cardamom agroecosystem. Spice India 6 (8) 13-15. Chandrasekar S S & Balu A 1993 Vertical distribution of thrips (Sciothrips cardam07ni Bagnall) in 8111a11 cardamom. J. Plantn. Crops 21 (Supp!.) : 227-230. Singh et al. Krishnamurthy K, Khan M M, Avaclhani K K, Venkatesh J, Siddaramaiah A L, Chakravarthy A K & Gurtlmurthy B R 1989 Three Decades of Carda-mom Research at Regional Rp-searcb Station, Mudigere (19,,8-1988). Station Bulletin No.2, Re-gional Research Station, Mudigere, Karnatalca. Singh J, Sudharshan M R & Kuman:san D 19.96 Evaluation of prOlnhiing selections ofcardamolll (CV. Malabar) for thrips (Sciothrips cardrrnwmiJ tolerance (Thysanoptera: Thripidae). J. Plantn. Crops 24 (Suppl) 283-285. Singh J, Sudharshan 1\1 R & Tam i I Selvan lVl 1995 Seasonal popul-ation fluctuation of cardamom thrips, Sciothrips cardanw7n; Hamk. (Thripidac : Thysanoptera). ,T. Appl. Zoo!. Res. 6 (2) : 101-104. 1 I I : 

Seasonal population of cardamom thrips (Sciothrips cardamomi (Ramk.) on three cultivar types of cardamom (Elettaria cardamomum Maton)

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Seasonal population of cardamom thrips (Sciothrips cardamomi (Ramk.) on three cultivar types of cardamom (Elettaria cardamomum Maton)

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