Only a small percentage of insect species are pests. However, pest species cause significant losses in agricultural and forest crops, and many are vectors of diseases. Currently, many scientists are focused on developing new tools to control insect populations, including secondary plant metabolites, e.g., alkaloids, glycoalkaloids, terpenoids, organic acids and alcohols, which show promise for use in plant protection. These compounds can affect insects at all levels of biological organization, but their action generally disturbs cellular and physiological processes, e.g., by altering redox balance, hormonal regulation, neuronal signalization or reproduction in exposed individuals. Secondary plant metabolites cause toxic effects that can be observed at both lethal and sublethal levels, but the most important effect is repellence. Plants from the Solanaceae family, which contains numerous economically and ecologically important species, produce various substances that affect insects belonging to most orders, particularly herbivorous insects and other pests. Many compounds possess insecticidal properties, but they are also classified as molluscides, acaricides, nematocides, fungicides and bactericides. In this paper, we present data on the sublethal and lethal toxicity caused by pure metabolites and crude extracts obtained from Solanaceae plants. Pure substances as well as water and/or alcohol extracts cause lethal and sublethal effects in insects, which is important from the economical point of view. We discuss the results of our study and their relevance to plant protection and management.

Galleria mellonella L. larvae were reared on a standard diet amended with varying concentrations (0, 0.0015, 0.015, 0.15, and 1.5%) of the benzimidazole-derivative antihelmintic drug oxfendazole. Survivorship, developmental times, longevity, fecundity, and fertility were monitored over the treatments. Relative to the untreated control, exposure to diet containing 1.5% oxfendazole significantly decreased survivorship in larval, pupal, and adult stages, prolonged the time to reach the adult stage, and reduced adult longevity. Oxfendazole at all concentrations significantly lowered egg production per female and decreased egg hatch. These results demonstrate that this antihelmintic may be explored as a candidate for insect pest control.

Benzimidazole antihelmintics, including mebendazole, have a broad antiparasitic spectrum. These drugs play a major role in the treatments of parasites of intestines or other organs of vertebrates, humans, and other animals. The impact of mebendazole on the biology of the greater wax moth, Galleria mellonella (L.), was assessed by observation of several developmental parameters as follows: survivorship, developmental time, and adult longevity. Sublethal toxicity was measured through reproductive parameters such as fecundity and hatchability. The larvae were reared on artificial diet from first-instar larvae to the adult stage in the laboratory. The diets contained mebendazole at different concentrations of 0.005, 0.05, 0.5, or 1.0%. Control diet did not contain mebendazole and produced seventh-instar larvae in 96.6 ± 1.67% of cases, whereas the addition of mebendazole into diet at 1.0% significantly decreased survivorship of seventh-instar larvae to 79.9 ± 4.08%. The diet with the highest concentration of mebendazole decreased survivorship in the adult stage from 79.9 ± 2.35 to 56.6 ± 4.73%, and shortened the developmental time for adult emergence from 36.7 ± 0.48 to 34.1 ± 0.63 d. All mebendazole concentrations shortened adult longevity and significantly decreased fecundity and hatchability of G. mellonella. The highest dietary concentration of this antihelmintic significantly decreased the egg number to 28.6 ± 2.89 and hatching rate to 51.7 ± 1.85%. The present study demonstrates that mebendazole exhibits significant adverse effects on greater wax moth, leading to deteriorated life table parameters and decreased adult fitness.

The fruit fly Drosophila melanogaster (Meigen) (Diptera: Drosophilidae) is often used in various biological, molecular, and toxicological studies. Sodium tetraborate, a boron compound, was added to the artificial diet of developing D. melanogaster to determine its effects on adult longevity and fecundity. Insects reared from first instars to adults on diets containing 10, 30, 150, 300, or 400 mg/liter sodium tetraborate showed that the highest concentration (400 mg/liter) significantly reduced female longevity (31.65 ± 4.02 [mean ± SD] d for the controls versus 1.87 ± 0.30 d for 400 mg/liter) and male longevity (32.80 ± 1.96 d for controls versus 3.57 ± 0.42 d for 400 mg/liter). Females from the control diet produced 9.46 ± 0.57 (mean ± SD) eggs per female, whereas those fed on a diet containing 300 mg/liter produced only 1.92 ± 0.30 eggs per females. These results expand our knowledge of the impact of sodium tetraborate on various insects and indicate that boron compounds should be further inve...