Abstract
th instar larvae of B. mori was evaluated. Results revealed that injection with E. coli increased the total haemocytes counts (THCs) to about 59.09% of the control at 24 h post-infection. In this respect, B. thuringeinsis decreased the THCs by about 45.9, 58.39 and 69.4%, respectively, than control after 48 h post-infection at concentrations of 0.5, 1 and 1.5 ppm. Injection with E. coli increased the number of Pr, Pl, Gr and Oe. On the contrary, injection with B. thuringeinsis significantly decreased the number of Pr, Pl and Gr and Oe. The mutagenic effect of the bacterial injection produced and/or affected several proteins that killed or caused larval deformation through the alteration of the physiological and genetic processes.
Highlights
The silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) has been exploited as a silk producer in the silk industry for thousands of years
We studied the effect of some immunity responses of silkworm larvae such as, cellular immunity against E. coli (G-) and B. thurengensis (G+) bacteria and studied the effects of both E. coli and B. thurengensis at concentration of 1.5 ppm on the corpora allata (CA) activity during the last larval instar of B. mori to understand the effect of both bacteria on activation or inhibition of the CA activity and its relation with total and differential haemocytes counts
B. mori fifth larval instar with E. coli markedly increased the CA surface area at 72 and 120 h post-infection to about 18.9 and 24.9%, respectively of the control. This increase may be due to the effect of E. coli on the immunity response of larvae .These results are in accordance with findings of Freitak et al (2007) who demonstrated that injection of Gram negative bacteria E. coli can induce the immune response of lepidopteran larvae
Summary
The silkworm, Bombyx mori L. (Lepidoptera: Bombycidae) has been exploited as a silk producer in the silk industry for thousands of years. The recent success of transgenesis of the silkworm has opened new prospects for this insect species (Tamura et al, 2000). Silkworm diseases are the most important disease that inflect heavy loss to crops. Most losses in sericulture can be attributed directly to silkworm diseases. Bacterial diseases are common, but in general, massive outbreaks are rare. When silkworms are physiologically weak, bacterial diseases can attack them, eliciting a heavy toll on sericulture (Aruga, 1994). The bacterial diseases affecting silkworm are called flacherie because the cadavers of silkworms that have died of these diseases lose elasticity, soften, and rot. Bacterial diseases of silkworms are usually only secondary to virus diseases.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
