PRELIMINARY STUDIES ON THE BIOLOGY OF HORNED GALL APHID IN THE GALL AND THE GROWTH OF THE GALL

One of the Chinese gallnuts is the gall caused by horned gall aphid, Schlechtendalia chinensis (Bell), which amounts to about 80 per cent of the total output of gallnuts. Life of the aphid in the gall lasted some 4.5-5 months with three forms and four generations, stem-mother, two generations of apterous female, and autumn-form winged viviparous female. The gall grows gradually with an increase in quantity of the aphids, and the increase of aphids has been doubled and redoubled during the period from the beginning to the end of the reproduction of two generations of papterous viviparous female but the growth of the gall does not do so. In the later stage of growth of the gall, though the number of the aphids increases a little, sometimes even does not increase any more, the gall grows speedily still. Therefore, the longer the growth period, the bigger the gall size before natural burst of the gall.