Total toxicity of two types of mineral oil (from Zakum and Kuwait) was determined with respect to hydrobionts of the Antarctic ecosystem. Crustacean — Euphausia superba proved to be sensitive to hydrocarbon pollution of the sea environment (LC50 x 48 h-1 = 7.62 ppm). Fish — Notothenia rossi marmorata showed much lower sensitivity.

The use of Bacillus thuringiensis (Bt) to control insect pests has already been established in various agronomic and forest crops. It is a bacterium that does not pollute the environment, is safe for mammals and vertebrates, lacks toxicity to plants and specifically targets insects. To date in-depth studies have not been conducted about the use of Bt to control the main pest of mahogany (Swietenia macrophylla King) and other Meliaceae species, the Hypsipyla grandella Zeller (Lepidoptera: Pyralidae). Therefore, this study aimed to test the pathogenicity of Bt strains on H. grandella caterpillars, as well to determine the lethal concentration required to kill 50% of the population (LC50) of the most promising strains. Ten strains of Bt toxic to lepidopteran proven in previous trials were used and these were incorporated into a natural diet with mahogany seeds to check their mortality. The LC50 of the top five strains was determined. The results indicate that H. grandella is highly susceptible to Bt toxins and the S1905 strain is highly toxic. Therefore, the use of Bt strains may be a tool to be incorporated into the integrated management of this important pest.

The influence of bean seed surface lipids on infestation of seeds by Acanthoscelides obtectus Say was investigated. The experiments were performed in dual-choice bioassays on three bean varieties: Blanka, Bor and Longina. The collected data for natural and solvent washed seeds concerned the number of ovipositions, embryo mortality, lack of seed-boring activity, dead larvae inside seeds and developed insects. The results clearly indicated that bean seed surface lipids are involved in all infestation stages, and could be used to distinguish resistant and non-resistant varieties of been. Chemical analyses revealed the following groups of surface lipids: wax esters, long chain primary alcohols, n-alkanes, sterols, fatty acids, squalene, aldehydes, monoacylglycerols, ketones and fatty acid esters. Quantitative composition of surface lipids was analysed using selected chemometric procedures to determine correlation with bioactivity. Cluster analysis of surface lipid composition enabled to distinguish resistant and non-resistant varieties. Fatty acids and monoacylglycerols were found to deter bean weevil infestation, while alkan-1-ols acted as attractants.