The protection of horticultural crops from slug feeding can be achieved using slug pellets; however, application of molluscicides is not always safe for the environment. There is a need for alternative methods to reduce the palatability of crop plants. Chemical properties of secondary compounds from lichens influence the feeding behaviour of slugs. Liquid extracts of three lichen species (Cladonia rangiferina (L.) F.H. Wigg., Cladonia stellaris (Opiz) Pouzar & Vězda, and Pseudevernia furfuracea (L.) Zopf) were applied to three different crops and tested for their antifeedant properties against an important agricultural pest, the Spanish slug (Arion vulgaris Moquin-Tandon, 1855). All three extracts had specific activity, showing a decrease in grazing intensity as well as slug mass loss after feeding on treated food. Slugs significantly gained mass after feeding under control condition; however, they did not gain mass when fed on extract-treated food. The most effective extract was from P. furfuracea. We propose to use properties of lichen extracts to develop new environmentally friendly molluscicides.

The research summarizes information on biochemical processes of biogas production and the parameters that affect the results of its production. The research examines the result of obtaining biogas from bog sludge and a mixture of crushed reed. Particular attention is given to temperature, as a parameter that affects the results of methane and biogas production.The yield of biogas and methane during the bioprocess depends on the effect of temperature. During the experiment, 2.78 L of biogas with an average methane content of 38.7% was obtained from a mixture of bog sludge and crushed reeds. If the content of organic compounds in the sludge was higher, the biogas yield would increase during the process. It is more advantageous to use the raw material mixture for biogas production.

The research explores the possibilities of biogas extraction from aquaculture waste. Samples of fish-farming pool sludge were taken from a fish farm, which is located in the Krāslava district, Kalnieši rural municipality. Prior to experimental fermentation and extraction of biogas, samples were analyzed in order to determine their moisture and organic matter content (OMC). For purpose of increasing OMC available for fermentation, sludge was mixed with crushed reeds. Biogas was obtained from the samples at various ratios of sludge and reed residues. During the experiments, 3.81 liters of biogas were obtained from a mixture of fish-farming pool sludge and crushed reed at reed mass 100 g. The results of experimental research indicate that aquaculture residues can be used to produce biogas.