Biological and Biochemical Effects of Bacillus Thuringiensis, Serratia Marcescens and Teflubenzuron on Cotton Leafworm

Abstract

Two biopesticides Serratia marcescens [Eubacteriales:Enterobacteria] (used at MC 50 , concentration caused 50% malformation )and Bacillus thuringiensis Var. kurstaki (used at LC 50 ) and insect growth regulator Teflubenzuron (used at LC 50 value) were used for treatment of larvae of cotton leaf worm , Spodoptera littoralis (Boisd.) . Sequential combined Effect was carried out by treating 2 nd instar larvae with LC 50 value of B. thuringiensis or Teflubenzuron then the larvae allowed to pupate on sawdust treated with S. marcescens at MC 50 .The effect of these three agents were assessed by toxicity , fecundity , fertility , phosphatases activity and total carbohydrates . The obtained results revealed that Teflubenzuron is a potent toxin ( LC 50 = 0.113 ppm ) compared to B. thuringiensis ( LC 50 = 165.64 ppm ). On the other hand, the mode of action of S. marcescens is through malformation, the malformation concentration fifty (MC 50 ) is 3.09x10 8 colony forming unit/ml (cfu/ml) . All treatments caused a significant reduction in fecundity and fertility. The sequential combined effect showed more reducing effect on the fecundity and fertility than the individual treatments. Moreover, the activity of phosphatases and total carbohydrates were significantly fluctuated during the different periods of pupal stage. The sequential combined effect of Teflubenzuron with S.marcescence caused more significant effect on alkaline phosphatase activity than the individual treatment with S.marcescence but it was somewhat similar to Teflubenzuron. Also the sequential combined effect treatment of B. thureinginsis with S.marcescence had more effect than the individual treatment either with S.marcescence or B. thureinginsis. Moreover, all treatments caused significant decreases in total carbohydrates during the pupal stage and the sequential combined effect treatments had more decreasing effect than the individual treatments. According to the obtained result, S.marcescence could be considered as a biopesticide , and become more effective when used in sequential treatment with either Teflubenzuron or B. thuringiensis .

Potential Insecticidal Effect of a Wasp (<i>Polistes dominulus</i>) and a Bee (<i>Apis mellifera</i>) Venoms in Controlling <i>Spodoptera littoralis</i>

“…This may be due to the fact that venoms of both bees and wasps are being used as defensive agents against predators, competitors, and pathogens. These venoms are particularly rich in neurotoxic, cytolytic and antimicrobial peptides that fulfill key roles in capture and conservation of praise, defense against competitors [31] that agree with [32] that indicates the insecticidal activity of ectoparasitoid wasp on the cotton boll worm. Aiming at underlying the potential of venom approaches for pharmaceutical discovery different application types for social bee and wasp venom were significantly (χ 2 = 239.47, d.f.…”

Comparative Biological and Biochemical Assessment for Toxicological Profile of Some Eco-Friendly Insecticides Applied for Controlling of the Fourth Instar Larvae of Spodoptera Frugiperda

“…The biochemical analyses elucidated that carbohydrate level was decreased after Btk exposure, which may be owing to the urgent need of bacteria to glucose as major source for energy for propagation and growth. Thus, bacteria utilize carbohydrates as carbon source for energy and built a new cell; this may decrease the available carbohydrates for treated insect, especially glucose, which plays an important role in energy supply, adult maturation, and builds up a new chitin [29,30] . The decrease in the total protein content either by chlorfluazuron or Btk was because of the binding of protein with foreign tested compounds [29] .…”

Latent Effect of Certain Ovicidal Compounds LC50 on Some Biological and Biochemical Parameters of Pink Bollworm, Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae)

“…The mean values For Phynoloxidase activity were 13.0 , 18.0 , 16.9 and 23.0 (O.D.units/g.b.wt) , for Teflubenzuron and Lufenuron, Flufenoxuron and control, respectively .For N-acytel-glucceamine the mean values were (µg 105.3 ,97.6,124.3,and 264.0 (µg NAGA /g.b.wt) for Teflubenzuron Lufenuron, Flufenoxuron, and control, respectively. In addition, the chitinase activity of P. gossypiella resulted from eggs treated with three IGRs Teflubenzuron, Lufenuron and Flufenoxuron,caused highly increased to 4567.0, 369.0 and 466.0 (µg NAGA x103/min/g.b.wt / larvae), respectively, compared to (277.0 µg NAGA x103/min/g.b.wt / larvae) control ( El-Sheikh et al, 2013;Said et al, 2017;El-Naggar, 2013;Bakr et al, 2013and Tanani et al, 2015.…”