Jitendra Sonkar,, Jayalaxmi Ganguli and R.N. Ganguli

Transcription

1 Agric. Sci. Digest, 32 (3): , 2012 AGRICULTURAL RESEARCH COMMUNICATION CENTRE ccjournals.com / indianjournals.com nals.com STUDIES ON CORRELATION OF PHEROMONE TRAP CATCH CH OF H.ARMIGERA (HUBNER) WITH LARV ARVAL AL POPUL ULATION IN FIELD AND WEATHER PARAMETERS Jitendra Sonkar,, Jayalaxmi Ganguli and R.N. Ganguli College of Agriculture, Indira Gandhi Agricultural University, Raipur , India Received : Accepted: ABSTRACT Correlation between pheromone trap catch and larval population of Helicoverpa armigera (Hub.) and influence of weather parameters with moth population was studied during December- April Data indicated that the H.armigera moth was first trapped in 2 fortnight of December with an average of 2.55 moths /trap and showed two peaks i.e in 1 fortnight of January and 2 fortnight of March, ch, respectively espectively.. The correlation between moth population and next xt fortnight larval population of H.armigera and mean relative humidity was found to be positively significant while correlation with maximum temperature, minimum temperature, and sun shine hours was found negative but non-significant. Key words: Helicoverpa armigera, pheromone, correlation. INTRODUCTION Chick pea is one of the dominant pulse crops of northern and central India grown primarily on conserved moisture in Rabi season. In Chhattisgarh state where rice based cropping system is predominant; chick pea is becoming an important crop in the Rabi season. Currently, it is grown in an area of thousand hectare with an annual production of thousand tons and with productivity 998 kg/ha, (Annonymous,2009). The gram caterpillar, Helicoverpa armigera (Hub.) is typical polyphagous insect that attacks and develops on a large variety of crop plants and ornamentals. Pest population is affected by weather factors so by monitoring and resolving peak period of occurrence by light or pheromone traps we can forecast the pest outbreak and try to control them before causing economic damage. MATERIALS AND METHODS In the present studies for studying the correlation of adult moth emergence of H.armigera with the larval population in the field, pheromone trap were of 3 traps /acre. The septa of the pheromone trap were changed after every 20 *Corresponding author jayaganguli@yahoo.com days. Male moths of H.armigera caught in the all the pheromone traps were recorded daily and fortnightly mean was computed. The data thus generated was correlated with the corresponding larval population in the field and weather parameters during December-April, RESULTS AND DISCUSSION Seasonal fluctuation of moth population of H. armigera and its peak activity was observed during the study period. The moths were first trapped on 2 nd fortnight of December with an average of 2.55moths / trap. The population suddenly increased and reached at its peak of 3.53 moths / trap in 1 st fortnight of January. Thereafter in next four fortnights the population of moths went down and it ranged moths/trap. In 2 nd fortnight of March an increase was observed with 3.25 moths /trap. In 1 st fortnight of April lowest catch of 1.47moths /trap was recorded. (Table 1& Fig.1) The correlation between moth population and next fortnight larval population was worked out and found to be positively significant r = Regression equation for larval population was worked out to be Y= x (Table. 2 & Fig.2)

2 Vol. 32, No. 3, TABLE 1: Correlation between mean numbers of moths of H.armigera caught in pheromone trap with corresponding meteorological data Month Fort Date No. of Max m Min m Mean Sunshine night moth temp. temp. RH (%) (Hrs/day) ( O C) ( O C) December 2 nd 16 to January 1 st 01to January 2 nd 16 to February 1 st 01to February 2 nd 16 to March 1 st 01to March 2 nd 16 to April 1 st 01 to Correlation with number of moths FIG. 1: Moth population trapped in pheromone trap (Fortnightly mean) TABLE 2: Correlation between number of moths caught in pheromone trap with next fortnight mean larval population Pheromone trap observations Larval population observations No. Fort Month Date Number of moths Fort Night Month Date LarvalPopulation night 1 2 nd December 16 to st January 01 to st January 01to nd January 16 to nd January 16 to st February 01 to st February 01to nd February 16 to nd February 16 to st March 01 to st March 01to nd March 16 to nd March 16 to st April 01 to Correlation 0.86

3 206 AGRICULTURAL SCIENCE DIGEST FIG. 2: Regression of larval population on mean maximum temperature. FIG. 3: Regression of moth population on mean maximum temperature. The trends of present investigations are similar to the findings of Lal et al., (1985) and Srivastava and Srivastava, (2009). Lal et al., (1985) reported that larval activity of H.armigera in chickpea fields showed that the peak population densities were preceded by a peak in moth catches while Srivastava and Srivastava, (2009) reported that correlation between pheromone trap catches of week (n-1) and egg counts for week (n=0) were positive, r = in 1986 and positive and significant r = in 1987also correlations between egg counts of week and larval counts for week were also (n 1) (n=0)

4 Vol. 32, No. 3, FIG. 4: Regression of moth population on mean relative humidity. FIG. 5: Regression of moth population on mean sunshine hours.

5 208 AGRICULTURAL SCIENCE DIGEST significant and positive, r = and for the years 1986 and Maximum temperature The association between average number of moths per trap and mean maximum temperature was worked out. The r value for the two variable was found to be non-significant and negatively correlated and negative, ie (r = -0.33) and regression equation for moth population was Y = x (Fig.2) Verma and Sankhyan, (1993) also observed that the maximum temperature was negatively correlated with the moth population of H. armigera which is similar to present findings. REFERENCES Anonymous, (2009) Area, production and productivity of chickpea from to in Chhattisgarh. Directorate of Agriculture, Raipur.(C.G.) Lal, S.S.; Sachan, J.N. and Yadava, C.P. (1985) Sex pheromone trap - a novel tool for monitoring gram pod borer populations. Plant-Protection-Bulletin, India. 37 pp Srivastava;C.P.and Srivastava;R.P.(2009). Monitoring of Helicoverpa. armigera (Hbn.) by pheromone trapping in chickpea (Cicer arietinum L.). J Applied Ent; Verma, A.K. and Sankhyan, S. (1993). Pheromone monitoring of Helicoverpa armigera (Hubner) and relationship of moth activity with larval infestation on important cash crops in mid-hills of Himachal Pradesh. Pest Management Econ Zool, 1993:1(1) pp