The chemosterilizing activity of some mycotoxins and their influence on the development and survival of Spodoptera littoralis (Boisd.) (Lep., Noctuidae)

Abstract

The effects of four mycotoxins: aflatoxin B1 (AFB2), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1) and kojic acid (KA) on Spodoptera littoralis were investigated. Second instar larvae were allowed to feed on an artificial diet containing various concentrations of either AFB1 (0.5, 1, 2, 2.5, 3 and 3.5 ppm), AFB2 (2, 3 and 4 ppm), AFG1 (1, 2, 3 and 4 ppm), or KA (up to 100 ppm). Mortality, development time, fecundity, egg hatchability and adult longevity were determined for each treatment and compared to control values. AFB1 (2–3.5 ppm) and AFG1 (3 and 4 ppm) delayed the larval and pupal development and reduced the fecundity and hatchability. AFB2 (4 ppm) reduced fecundity and hatchability but did not affect the development rate. The highest mortality was caused by AFB1 (3.5 ppm). KA had no remarkable effect when given alone, even in concentrations up to 100 ppm. Yet it potentiated the toxicity and sterilizing activity of AFB1. A combination of AFB1 (3.5 ppm) and KA (75 ppm) caused more than 92% sterility among male and female moths. Sterilized males exhibited good, though not fully equal, mating competitiveness against control males. The possibility of making use of the chemosterilizing activity of these mycotoxins is discussed.

Antifeedant and toxic activity of Adhatoda vasica leaf extract against Spodoptera littoralis (Lep., Noctuidae)

“…The antifeedant activity of the crude extract against the neonate larvae was investigated through choice bioassays using artificial diet discs. The diet, based on wheat germ and casein, was prepared according to Singh (1983), with a slight modification regarding the vitamins and water content as mentioned by Sadek et al. (1996).…”

“…The antifeedant activity of the crude extract against the neonate larvae was investigated through choice bioassays using artificial diet discs. The diet, based on wheat germ and casein, was prepared according to Singh (1983), with a slight modification regarding the vitamins and water content as mentioned by Sadek et al (1996). After preparing the diet in the laboratory, aliquots of 5 ml methanol solution containing different proportions of the extract, were added to 95 g amounts of the diet during the normal course of cooling (between 60 and 55°C).…”

Protein Metabolism in Larvae of the Cotton Leaf-WormSpodoptera littoralis(Lepidoptera: Noctuidae) and Its Response to Three Mycotoxins

“…In this study we found that AFB 1 obstructs protein metabolism more strongly than AFG 1 . In a previous study (Sadek et al 1996) we also found that AFB 1 is more toxic and more effective as a sterilizing agent than AFG 1 . These results are consistent with those observed on the same species by Megalla et al (1984) and Abdou et al (1984Abdou et al ( , 1985.…”

“…The sixth-instar larvae were fed diets containing AFB 1 (2.5 ppm), AFB 2 (4 ppm), or AFG 1 (4 ppm). These concentrations of toxins were chosen (preliminarily) after the observation of their effects on development rate and fecundity (Sadek et al 1996). Large differences between the effects of the three toxins on the incorporation of phenylalanine into protein were found.…”

“…Dietary aßatoxins also adversely affect larval and pupal development as well as the fertility of the moth (Sadek et al 1996). It was stated that mycotoxins interfere with the phosphorylation of intracellular proteins and inhibit protein translation in insect cells (Dumas et al 1996, Liu et al 1996, Boucias et al 1998.…”