With respect to silk filament weight, larvae in the second group (treated topically with pyriproxyfen 10 μg and fed on mulberry leaves treated with glycine 1%) recorded the highest mean (0.497 g) at fifth day of fifth larval instar followed by (0.391 g) for larvae fed on mulberry leaves treated with glycine 1%. Meanwhile, the lowest filament weight (0.292 g) was recorded with (JHA) pyriproxyfen treatment at second day, regardless the concentration.