author(s)
SA Wani, ST Ahmad

abstract
White morph of Chromaphis juglandicola Kalt. has been reported for the first time by the authors during present study undertaken in Kashmir valley. Laboratory investigations comparing the two colour morphs did not show any difference in the developmental characteristics of white and yellow aphids, but a slight reproductive advantage for white morphs. The reproductive rate of white morph was greater over first two days of adult life with mean values of 6.5 and 11.1 nymphs, while that of yellow ones was 2.7 and 4.6 nymphs (p < 0.05) for 1st and 2nd days respectively. Of the walnut aphid population present in the orchards of the valley, white morph accounted for zero to 35% in the month of May, 2013 and 77.6% to 93% in the month of September, 2013. Percentage of aphids (both morphs) showed fluctuations during the years with a declining trend in numbers towards Oct-Nov. The percentage of white morph compared to yellow one increased during the same period.