SUSHIL KUMAR, H. R. DESAI, Z. P. PATEL, B. K. BHATTAND J. R. NAIK

Impact of climate and crop phenology on abundance of mango hopper was studied in mango cv. Alphonso under
field conditions from 1997 to 2007 at Agriculture Experimental Station, Navsari Agricultural University, Paria, Gujarat.
Overall average hopper population (irrespective of crop stages) was 1.31/twig or panicle. During peak activity year (2005-
2006), highest hopper population was 5.74 (peak 29.70 at 8 Standard week)/twig or panicle when maximum, minimum and
average temperatures were 31.19, 18.73 and 24.96 °C, respectively. Relative humidities during the same year were 89.16
(morning), 59.55 (evening) and 74.35 (average) per cent, respectively. Rainfall, rainfall days, sun shine and wind velocity
were 60.99 mm, 1.60, 7.55 hours and 3.72 km/hours, respectively. During this period, hopper population exhibited
significant positive correlation with maximum temperature ('r' = 0.3864) and sun shine ('r' = 0.4351). While, hopper
population indicated significant negative correlation with minimum and average temperature ('r' = - 0.4652 and – 0.3031),
evening and average relative humidity ('r' = -0.5102 and -0.4737) and rainfall days ('r' = -0.4181).Total contribution of all the
abiotic factors on fluctuation of hopper population during 2005-2006 was 35.71 per cent (R= 0.6673 significant at 1%level).
Hopper population during the peak activity year peaked on pea cum marble stage of the crop (25.99/panicle) followed by
13.76 hoppers at stone sized fruit stage of the crop. So, it may be concluded that most critical weather condition for peak
abundance of hopper population during peak activity year was 33.74 (maximum), 12.14 (minimum) and 22.94 °C (average)
temperature, 41.42 (evening) and 65.21 per cent (average) relative humidity and 9.80 hours of sun shine. Slight increase in
temperature (minimum and average) (0.06 and 0.29 °C), relative humidity (1.32-3.20 %) and rainfall (17.09 mm) and slight
decrease in rainfall days (0.06), sunshine (0.12 hours/day) and wind velocity (0.50 kms/hour) are conducive for sharp rise in
hopper population.