The Importance of the Extending of Primary Reproducing Season of Living Silkworms in a Sharp Continental Climate Arias

When silkworm-eggs are survival bred in differential (step by step) method, it can be realized urgent silkworm breeding method and the breeding season would be finished before hottest days and coarsen of mulberry trees leaves. According to experiences, when the survival period was prolonged to 10-11 days, the delivery process was extended rather longer than usual 2-3 days. When this experience was rechecked in many districts, the delivery process of silkworm cocoons was prolonged to 17-18 days than usual 11-12 days, but before 75-80 % of receipt silkworm cocoons were realized in 4 days, and according to step by step method it was extended to 8 days.