Biological effects on silkworm larvae fed by mulberry leaves treated with carbendazim fungicide

The biological effects on silkworm larvae fed on mulberry leaves contaminated with 0.5 and 1 mg/ml carbendazim were analyzed in different periods. The fungicide was sprayed on trees with 0, 1, 2, 4 and 8 days intervals before the first feeding of second instar larvae. Carbendazim decreased the larval weight and the highest reduction was 4.5% decrease compared to control. One mg/ml of fungicide used immediately after treatment caused a significant decrease in female cocoon characteristics such as cocoon weight, pupa weight and shell weight by 8.4, 8.5 and 7.8, respectively. The rate of hatching had also decreased in some treatments. Economical traits of male insects and the number of laid eggs by females were not affected. In total, the mean of cocoon shell percentage in both sexes did not have any difference with control. Feeding from the leaves contaminated with carbendazim residue did not have significant effects on larval mortality and utilization of the leaves sprayed by this fungicide two days after application is recommended

Comparison of different multi-trait selection strategies for genetic improvement of economic traits in six Iranian commercial lines of the silkworm, Bombyx mori (Lep.: Bombycidae)

In this study, the genetic parameters and economic weights of some important economic traits in six Iranian commercial varieties (110, 107, 101433, Xinhong1, Koming1 and Y) of the silkworm were estimated and selection indices for these traits constructed. Individual recording of cocoon weight, shell weight and shell ratio were carried out during six generations. Heritabilities and genetic correlation between traits were estimated by restricted maximum likelihood method. The heritability of cocoon weight and shell weight were higher than that of shell ratio. Genetic improvement of cocoon weight and shell weight were high in the line 101433 due to higher heritability and genetic correlation between them. Therefore, the restriction of genetic gain of cocoon weight in this line is expected to cause a severe decrease in improvement of shell weight, and subsequently a decrease of selection efficiency. The genetic improvement of cocoon shell percentage increased in restricted indices due to low genetic correlation with cocoon weight, and selection accuracy in these indices decreased significantly compared to other indices. Considering the difference in genetic parameters and economic values of traits in commercial lines of the silkworm, it would be necessary to define a separate breeding goal and selection strategy in each line

Biochemical changes in haemolymph of silkworm larvae due to pyriproxyfen residue

An experiment was carried out to evaluate the effect of pyriproxyfen residue on silkworm. The mulberry leaves smeared with 0, 1, 10, 75, 150 and 500 ppm concentrations of pyriproxyfen were fed to silkworm larvae in the 1st day after 4th molting. Some biochemical traits of haemolymph such as glucose, urea, uric acid, cholesterol, total protein, alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase were measured. The results showed that in 24 h after using toxic leaves, the amount of these biochemical compounds significantly decreased in most treatments. These compounds after 120 h had different fluctuations and increased in some doses. (c) 2006 Elsevier Inc. All rights reserved

The Effects of a Juvenile Hormone Analog , Admiral , Application on Protein Meta bolism of Silkwor Bombyx mori (Lep.: Bombycidae)

به منظور ارزیابی اثرات شبه هورمون جوانی آدمیرال، بر متابولیسم پروتئین در لاروهای سن پنجم کرم ابریشم آزمایشی با 6 تیمار با طرح کرت‌های کاملا تصادفی اجرا گردید. برگ‌های توت آغشته به غلظت‌های 0، 1، 10، 75 ، 150 و 500 پی‌پی‌ام از سم، در اولین روز پس از چهارمین پوست‌اندازی به لاروهای کرم ابریشم خورانده شد. برخی از ترکیبات بیوشیمیایی مرتبط با متابولیسم نظیر پروتئین تام، اوره، اسید اوریک، آلانین آمینوترانسفراز، آسپارتات آمینو ترانسفراز در همولنف لاروها مورد اندازه‌گیری قرار گرفت. به غیر از اوره که اختلاف قابل ملاحظه‌ای را در بیشتر غلظت‌ها نشان نداد، مقدار کلیه‌ی ترکیبات بیوشیمیایی اندازه‌گیری شده کاهش معنی‌داری را در مقایسه با شاهد نشان دادند. بنابراین غلظت‌های مزبور علاوه اینکه مانع ورود لارو به مرحله شفیرگی می‌شود اثرات برگشت‌ناپذیری را بر متابولیسم پروتئین‌ها وارد می‌کند