During the spring season of 2019, the effect of two insecticides (Cymbush^®&Tracer^®) on larvae of Bombyx mori  L. were studied at Plant Protec. Dept. Fac. of Agric., Fayoum Univ. Insecticides were sprayed on mulberry trees by concentration 1ml/l . of Cymbush^® and 0.1ml/l. of Tracer^{®  .}Mulberry leaves were harvested on to three times (after 3,6,9,12 days).Results show that, the 5^th instar larval mortality percentages increased , where data ranged between 18.30% in Cymbush^® and 10.21% in Tracer^®  compared to 9.93% in control. While cocooning percentages, cocoon shell ratio and silk productivity were decreased when comparing to control, where data ranged between 74.00% in Cymbush^®, 89.08% in Tracer^®  , 12.00% in Cymbush^®,19.07% in Tracer^®  and 1.021cg/day in Cymbush^®, 1.800cg/day in Tracer^®  , respectively compared to 93.00%, 19.77% and 1.910cg/day in control, respectively.