Study of destruxin B and tea saponin, their interaction and synergism activities with Bacillus thuringiensis kurstaki against Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)

Abstract

This study reveals the individual and synergistic effects of destruxin B (DB) (mycotoxin from Metarhizium anisoplae), tea saponin (Ts) and Bacillus thuringiensis (Bt) against Spodoptera exigua. DB, Ts and Bt reduced the growth of neonate larvae by up to 91.30, 89.17 and 77.17%. EC 50 values of DB against 4th and 5th instars were 0.17 and 0.22 mg ml Ϫ1, 0.35 and 0.41 mg ml Ϫ1 against 4th and 5th instars for Ts and 0.0031 and 0.0035 mg ml Ϫ1 after being treated with Bt. The synergism of DB and Ts with Bt resulted in the increased efficiency of these chemicals as mortality percentages significantly increased up to 94.2% with DBϩTsϩBt followed by DBϩBt with 91.99% and were significantly higher than individual treatments of Bt 65.81% and Ts 76.66%. Nutritional analysis revealed the increased toxicity of DB and Ts in combination with Bt, but DBϩBt showed higher efficiency with minimal relative consumption rate (RCR) 2.69 mg/mg/day, relative growth rate (RGR) 1.33 mg/mg/day and efficiency of conversion of ingested food (ECI) 35.77%, respectively. Changes in antioxidant enzymes, superoxidase dismutase (SOD) and catalases (CAT), were noticed to some extent over different exposure times in all treatments. The highest SOD activity was observed in individual DB treatment, while individual Bt treatment caused the highest variation in CAT values. In all treatments, SOD and CAT values fell sharply on the final day except for individual Bt treatment, with which the values were relatively stable on the final day.

The production relationship of destruxins and blastospores of Metarhizium anisopliae with virulence against Plutella xylostella

“…Metarhizium anisopliae is an important entomopathogenic thuringiensis (Bt), Isaria javanicus, and botanical insecticides had synergistic effects (Hu et al 2007a;Rizwan-Ul-Haq et al 2009;Yin et al 2010). Therefore, it is meaningful to explore the fermentation conditions of destruxins.…”

Peer Review #1 of "Tea saponin reduces the damage of Ectropis obliqua to tea crops, and exerts reduced effects on the spiders Ebrechtella tricuspidata and Evarcha albaria compared to chemical insecticides (v0.1)"

“…Increased activity of detoxifying enzymes in insects represents a response to intoxication with insecticides or xenobiotics (Singh & Singh, 2000;Serebrov et al, 2006;Gopalakrishnan et al, 2011). Rizwan-ul-Haq et al (2009) evaluated the bioactivities of TS solution in Spodoptera exigua (Lepidoptera: Noctuidae), which provides some helpful information about activities of enzymes against TS which is involved in the resistance mechanism in insects. In this study, we found that the activities of GST significantly increased during the initial period following TS treatment, which suggests that this enzyme may act to detoxify TS.…”

Optimization of Microwave‐Assisted Extraction of Tea Saponin and Its Application on Cleaning of Historic Silks

“…[3]. Every year, plenty of oil-tea camellia seed cakes are produced after the process of oil production and treated as waste residues.…”

“…Tea saponin is a kind of non-ionic surfactant which has good foaming, emulsifying and decontaminating properties [1,2]. It plays important roles in daily chemical, food, pharmaceutical and agricultural industries [3,4]. As a kind of natural source surfactant, it is mild, safe and pollutionfree and efficient as detergent.…”

“…However, the residues contain a large amount of tea saponin (about 16 wt%) and other ingredients including water, flavonoid, polysaccharide, etc. [3]. In order to make full use of the wasted oil-tea camellia seed cake, it is important to separate tea saponin from the oil-tea camellia seed cake in an economical, efficient and pollution-free way and to develop its new applications.…”