Results concerning the effect of sonic ecological factors on the diapaused larvae of pink boliworm (PBW), Peclinophora gossypiella indicated that, when the diapaused larvae were picked from cotton seeds and examined, it was found that the rate of dead to alive larvae amounted (65. 5%:34.5%) and (39%:61%) during 1994/95 and 1995/96 seasons, respectively. Mortalities were due to natural mortality, bacterial & viral infections and effect of the parasitoids Pyemotes herfsi and Plinpia rob orator. Accumulation of low heat units raie has worked as larval mortality factor and it is important for timing and determining the size of PBW spring emergence. Results of biological and histological effects of the bioinsecticide (xentari) on the spiny boliworm (Earias insulana) — neonate larvae showed that xentari displayed latent effects during the subsequent stages. The achieved effects were: death in the various larval inslars due to feeding the neonate larvae for 2 days on contaminated artificial diet increase of larval and pupal duration and decrease of adult longevity and the number of deposited eggs per female in comparisoi to untreated check. Feeding the 4’ instar larvae of E. insulana on contaminated diet with xentari caused certain pathological effects in the mid-gut of the treated larvae. Cross sections of the mid-gut showed separation of the epitlielial cells from the basement membrane as well as elongation, vaculization and breakdown of larval epithelium mid-gut. Also, xentari caused disorganization and disintegration of preirophic membrane. Keywords: Bollworms — Bioinscclicide — Ecological factors.