Abstract: 【Aim】This study aims to understand the effects of different larval rearing densities of the mulberry borer, Diaphania pyloalis on their growth, development and reproduction.【Methods】 The growth, development and reproduction parameters including the developmental duration, larval survival rate, pupation rate, adult emergence rate, pupal weight, oviposition period and number of eggs laid per female of D. pyloalis reared at five different larval densities (130, 650, 1 300, 1 950 and 2 600 individuals/m²) were determined under the same condition in the laboratory. 【Results】 Larval density had influences on the growth, development and reproduction of D. pyloalis to varying degrees, and low or high larval density was not conducive to its growth, development and reproduction. There was no obvious difference in the growth, development and reproduction parameters of D. pyloalis reared at the larval densities of 1 300 and 1 950 individuals/m², both with excellent performance. The larval, pupal and adult duration of D. pyloalis reared at the larval density of 1 300 individuals/m² were 11.32, 6.33 and 5.31 d, respectively, and those reared at the larval density of 1 950 individuals/m² were 11.50, 6.00 and 5.47 d, respectively. The pupation rate, adult emergence rate, and larval survival rate of D. pyloalis reared at the larval density of 1 300 individuals/m² were 86.67%, 100% and 86.67%, respectively, and those reared at the larval density of 1 950 individuals/m2 were 84.44%, 94.74%, and 80.00%, respectively. When D. pyloalis larvae were reared at the densities of 1 300 and 1 950 individuals/m2, the oviposition periods of their adults reached more than 2.00 d, the numbers of eggs laid per female reached more than 55.00 grains, and the egg hatching rates were more than 90.00%, showing significant difference from those reared at the other larval densities. In addition, the larval density of D. pyloalis showed an extremely significant correlation with the larval survival rate.【Conclusion】 Larval density is an important factor affecting the growth, development and reproduction of D. pyloalis, and when the larval density is 1 300 individuals/m² or 1 950 individuals/m², it is conducive to the efficient establishment of its indoor populations.

Key words: Diaphania pyloalis, larval density, growth and development, reproduction