Seasonal Activity of Sogatella furcifera H.,Cnaphalocropcis medinalis G. and Mythimna separata W. in Relation to Weather Parameters in Central India Amit Kumar Sharma, Swati Barche And P. K. Mishra JNKVV, College of Agriculture, Tikamgarh (M.P.) Abstarct: Field experiment was conducted at research farm during Kharif 22 and 23 at Jawaharlal Nehru Krishi Vishwa Vidyalaya (JNKVV), Jabalpur. Standard design of light trap (Model SM-1) was used to collect valuable information on seasonal activity of three major insect pest species of paddy namely white backed plant hopper, rice leaf folder, army worm and to find out its relationship with weather parameters. Seasonal activity indicated that major activity period of Sogatella furcifera H., Cnaphalocrocis medinalis Gen and Mythimna separata W. was confined between August to December. Three to four peaks were observed in case of S. furcifera, C. medinalis which indicates completion of 3 generations during main cropping season while highest weekly peaks were observed during third week of September and November in case of Mythimna separata.consistently very high collection of these species in trap catches associated with their higher infestation in field during 23 compared to 22. This indicated that higher rainfall, lower mean maximum temperature and higher relative humidity were very favorable weather factors for development of these pest species in the year 23. Key Words: Light trap catches, paddy, Seasonal activity, Weather parameters. Introduction: Seasonal activities of insect pest species can be monitored very effectively through trap catches. In recent years use of light trap occupied an important place in entomological studies all over the world for survey, detection and control of insect pest population. All though much work has been done on use of light trap against pests of pulses, but very little information is available on pests of paddy in central India (Mahakaushal region of M.P.). Different workers have used the light trap against pests 19
of rice crop in different states including Tamil Nadu [9] and West Bengal [1]. Under Indian conditions, though paddy is attracted by a wide range of insect pests as compared to any other single crop but not much information is available on the incidence and population build up of rice pests under varying agro-climatic conditions. The losses in paddy crop are very high in Jabalpur district due to various insect pests viz. Sogatella furcifera H., Cnaphalocrosis medinalis Gen., Mythimna separata W., Grass hopper (complex) as major pest species and Nephotettix virescens folder, army worm and to find out its relationship with weather parameters. Material and Methods: Field experiment was conducted at research farm during Kharif 22 and 23 at Jawaharlal Nehru Krishi Vishwa Vidyalaya (JNKVV), Jabalpur. Standard design of light trap (Model SM-1) by using 8 watt mercury vapour lamp, was operated throughout July to December during both the crop seasons i.e. 22 and 23. Daily records of pest population are collected. Trap catch obtained during every night, Dist., Leptocorisa varicornis Dicladispa is an unbiased sample which represents armigera O., Tryporyza incertulas W., Nilaparvata lugens S. and Melanitis ismene C. as minor [3]. Hence an urgent need was felt to study the use of light trap as IPM tool in paddy crop. The present study is conducted to collect valuable information on seasonal activity of three major insect pest species of paddy namely white backed plant hopper, rice leaf relative activity of night flying insects active in neighborhood of the trap which is as per rough estimate is about 1 m radius around trap. The daily trap catches were converted to weekly totals and mean per day catch per week (Weakly means/day) where worked out. Division of weeks is based on calendar days i.e. I week (1 st to 7 th day), II week (8 th to 15 th 2
day), III week (16 th to 23 rd day) and IV week (24 th to 3 th /31 st day) Daily weather data namely rainfall, maximum temperature and relative humidity were collected from JNKVV Agro metrological observatory for the years 22 and 23, which is situated within one kilometer radius from the experimental field. The collected weather data has been checked for its quality before utilizing in this study. Weekly and monthly means are calculated from the daily weather values. Results and Discussion: Three insect pest species namely white backed plant hopper (Sogatella furcifera H.), rice leaf folder (Cnaphalocrocis medinalis Gen.) and army worm (Mythimna separata W.) were identified as most important pests of paddy in this region because they occurred in significantly high numbers in trap catches as well as in field also. Species wise weekly as well as monthly results of both years (Main activity season Kharif) are described below: White backed plant hopper- [Sogatella furcifera (Harvath)] Main activity season (Kharif 22): It is a major pest of paddy in this region. Pest appears in second week of August and activity continues up to December. The highest monthly catch was observed in October (1238) hoppers followed by November (871hoppers) (Table 1A) and highest weekly peak was observed in the first week of November and population declines thereafter (Fig.- 1). Main activity season (Kharif 23): Pest appeared in first week of August. Major activity period was August to November there was a distinct rise in population in multiple proportion every month up to highest monthly peak in November (42,14. hopper) (Table 1B). Highest weekly peak was observed in third week of November with 15, 81 hoppers (Fig. 1). Population curve revealed the presence of 3 to 4 peaks of catches, each successive peak being followed by gap of 15 to 2 days which coincides approximately with one life cycle 21
period, suggesting completion of three generations during main season. Observations made by earlier scientist [5] also showed that Sogatella furcifera and Nilaparvata lugens were active from September to December in trap catches in Chattisgarh, while activity of major paddy pests including Sogatella furcifera reached its peak in August-September in Karnal, Hariyana [8] and Delphacids are most abundant in October and November [1]. Rice leaf folder [Cnaphalocrocis medinalis (Guenee)] Main season activity- (Kharif 22) : It is a major pest of paddy in Jabalpur and also in other parts of central India. The pest first appears in second week of August and remains active up to December. The highest monthly peak was observed in November, 543 months (Table 1A) while the highest weekly peak was recorded in first week of November (194 moths) (Fig.-2). Main season activity- (Kharif 23): First appearance of pest was recorded in second week of August (162 moths). Major activity period was August to December. From August to October there was distinct rice in population in multiple proportions, every month, reaching to its highest monthly peak in October (13,346 moths) (Table 1A). Highest weekly peaks were recorded during fourth week of September (6,13 moths) and October (6,146 moths) (Fig. 2). Population then significantly declined during November (6,44 moths) and December (26 moths). The present findings are in accordance with findings of many workers [4] who also reported the appearance of rice leaf folder in second week of August and major peaks were reported during September and October in Balaghat (M.P.). Similar observations were made by Manisegaram and Letchoumanane (21) who reported major activity in August and September population curve shows three peaks and the gap (25 to 35 days) between 22
these peaks is coincided with one life cycle period of the pest which indicates the possibility of completion of three generation during main activity season [2]. Army worm [Mythimna separata (WIK.)] Main season activity (Kharif 22): The pest first appeared in the third week of August and reached to its highest monthly peak in November (299 moths) (Table 1 A)with highest weekly peak during first and second week of November (132 and 151moths respectively) (Fig 3). Main season activity (Kharif 23): The pest was totally absent during July (table 1B). The pest first appeared in third week of August (6 moths). Major activity period was August to December. Population raised sharply in September (611 moths) with slight fall in October, it again reached to its peak in November (63 moths). Highest weekly peaks were observed in third week of September (262 moths) and November (256 moths). moths). The distinct peaks in population curve (Fig-3) suggest completion of three generation during Kharif. Pest population in relation to weather parameters Comparative activity of three pest species in relation to weather factors was studied by analysis of total monthly catches in two different years i.e. 22 and 23, respectively and presented in table 2. Results clearly revealed a distinct difference in the activity of all three pest species in both years. Year 22 was a season of low activity while the activity of all the four most important species was distinctly much higher during 23 crop season i.e. crop season of 23 was most favorable for the activity of pest species. White backed plant hopper [Sogatella furcifera (Harwath)] : Data indicated (Table 2) that activity in crop season was extremely higher (77,617 hoppers) about 242 times Population than declined in December (118 23
higher as compared to 22 trap catch (2,923 hoppers). Rice leaf folder [Cnaphalocrocis medinalis (Gunee)] : Trap catches in 23 crop season (27,78moths) was 27 times higher compared to 22 trap catch (1,254 hoppers). Army worm [Mythimna separata ( Wlk.)]: The difference in trap catch of this pest was more than double. Trap catch in 23 was 1,63 moths while it was 617moths in 22 crop season. Analysis of three weather parameters namely rainfall, temperature (Maximum) and humidity indicate (Table 2) prevalence of higher rainfall during July (248.8 mm), September (537.7 mm) and October (72.5 mm), lower mean maximum temperature during August (29. C), September (28.3 C) and October (29.3 C) and distinctly higher humidity in September (94%) and October (93%) in the crop season of the year 23. development of Sogatella furcifera and Cnaphalocrocis medinalis, while it was moderately favorable in case of Mythimna separata. A significant positive correlation of C. medinalis population levels with rain fall and frequency of rainy days has been noted in the past [6] and monthly rainfall over 9 mm in November or December is favorable for outbreak of white backed plant hopper and serious drought in crop season inhibit the outbreak [12] and that of insect pests of rice attained peak during warm and humid months of August and September in Panjab [11]. Results on seasonal activity indicated that major activity period of Sogatella furcifera, Cnaphalocrocis medinalis and Mythimna separata was confined between August to December. Three to four peaks were observed in case of S. furcifera, C. medinalis which indicates competition of 3 Apparently, these environmental conditions seem to be highly favorable for the 24
Fig. 1 Weekly distribution of light trap catches of Sogatella furcifera during 22 and 23 at Jabalpur Total trap catch per week 22 1 9 8 7 6 5 4 3 2 1 Kharif 22 Kharif 23 18 16 14 12 1 8 6 4 2 Total tap catch per week 23 I II III IV I II III IV I II III IV I II III IV I II III IV I II III IV July Aug. Sept Oct Nov Dec. Week/Month Fig. 2 Weekly distribution of light trap catches of Cnaphalocrocis medinalis during 22 and 23 at Jabalpur 3 7 Total trap catch per week 22 25 2 15 1 5 Kharif 22 Kharif 23 6 5 4 3 2 1 Total tap catch per week 23 I II III IV I II III IV I II III IV I II III IV I II III IV I II III IV July Aug. Sept. Oct. Nov. Dec. Week/Month 25
Fig. 3 Weekly distribution of light trap catches of Mythimna separata during 22 and 23 at Jabalpur 3 Kharif 22 3 Total trap catch per week 22 25 2 15 1 5 Kharif 23 25 2 15 1 5 Total trap catch per week 23 I II III IV I II III IV I II III IV I II III IV I II III IV I II III IV July Aug. Sept. Oct. Nov. Dec. Week/Month Table 1, A: Seasonal activity of major insect pest species of paddy collected in light trap during main activity season (Kharif 22). Month Total trap catch/month (3 days collection) Sogatella furcifera Cnaphalocrocis medinalis Mythimna separata July August 384 121 9 September 43 225 77 October 1238 365 232 November 871 543 299 December 48 174 73 Total catch of a 3331 1428 69 season 26
Table 1 B: Seasonal activity of major insect pest species of paddy collected in light trap during main activity season (Kharif 23) Month Sogatella furcifera Total trap catch/month (3 days collection) Cnaphalocrocis medinalis Mythimna separata July August 1228 498 37 September 923 744 611 October 25172 13346 379 November 4214 644 63 December 2823 26 118 Total catch of a season 844 27984 1748 Table 2 Monthly catches of four major pest species of Paddy and weather parameters at Jabalpur. Month/ Year Weather Parameters Sogatella Cnaphalocroci Mythimna Maximum furcifera s medinalis seporata Relative Rainfall (mm.) Temperature Humidity (%) ( C) 22 23 22 23 22 23 22 23 22 23 22 23 August 384 1228 121 498 9 37 745.6 532.6 29.5 29. 91 92 September 43 923 225 744 77 611 239.3 537.7 3.6 28.3 88 94 October 1238 25172 365 1333 232 379 21. 72.5 32.2 29.2 86 93 November 871 4214 543 644 299 63. 17.4 31.2 26.8 78 89 Total/Mean 2923 77617 1254 2778 617 163 15.9 116.2 3.9 28.3 86 92 27
generations during main cropping season while highest weekly peaks were observed during third week of September and November in case of Mythimna separata.consistently very high collection of these species in trap catches associated with their higher infestation in field during 23 compared to 22. This indicated that higher rainfall (116.2 mm.), lower mean maximum temperature (28.3 C) and higher relative humidity (92%) were very favorable weather factors for development of these pest species in the year 23.This information further strengthened the importance of light trap in monitoring the pest activity and its scope as IPM tool in the management of major pest species of rice in central India. References: 1. Ammar, E.D., Lomie, O. and Khadir, T.A. (1978). Population of leaf hopper in Egypt, from 1973 to 1975, as indicated by sweep net samples. Int. Rice Res. News lett. 3(2) : 12-13. 2. Chang, C.H. and Wu, S.C. (1999). Population dynamics and forecasting of rice leaf foler, Cnaphalocrocis medinalis Guenee in Tiwan. Plant Prote. Bull. Taipai 41(3) : 199-213. 3. Dubey,O.P. (197). Effect of date of planting and fertilizer doses on the incidence of major pests of paddy with particular reference to Sogatella furcifera Horv. Unpublished M.Sc. Thesis, JNKVV, Jabalpur. 4. Harinkhere, J.P., Kandalkar, V.S.,and Bhomik, A.K. (1998). Seasonal abundance and association of light trap catches with field incidence of rice leaf folder (Cnaphalocrocis medinalis G.). Oryza 35(1) : 91-92. 5. Kerketta, M.S., Dubey, A.K. and Kaushik, U.K. (199). Light trap studies of two rice plant hoppers, Nilaparvata lugens and Sogatella furcifera in relation to field population. Oryza 27(4): 53-56. 28
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