Biological Effects of Alginite on Tomato Plants (Lycopersicon esculentum) and Some Insects (Leptinotarsa decemlineata, Galleria mellonella and Halyomorpha halys)

The purpose of our work was to study the effect of Slovak origin alginite on germination of tomato seeds, growth and development of plants, as well as to evaluate biological activity of alginite against to insect pests. Tomato seeds with low germination capacity were treated by immersion in alginite solutions of concentration 0.0001–0.1 %. Alginite solutions with concentrations of 0.1–5.0 % were used for testing against insects. The application of alginite solutions significantly increases the germination of tomato seeds in laboratory conditions by 9.2–13.0 %. There was a significant increase in the length of seedlings and roots by 1.87-2.98 cm and 3.54–4.51 cm. In a greenhouse presowing treatment of tomato seeds with 0.001 % alginite solution significantly increased germination in comparison with the control (by 33.2 %) and 0.01 and 0.1 % alginite solutions (by 22.2 and 25.0 %). Monitoring of plant height showed that a month after the first seedlings emergence the average plant height was significantly higher in the variant 0.001% alginite solution and reached to 11.41 cm. The yield of fruits in the variants treated with alginite solutions significantly exceeded the control by 316.53–327.71 g per one tomato bush. It was found that alginite solutions at a concentration of 0.1–1.0 % had low ovicidal (2.73–13.19 %) and insecticidal (5.0–33.3 %) effects against insects belonging to different orders – Leptinotarsa decemlineata (Coleoptera), Galleria mellonella (Lepidoptera) and Halyomorpha halys (Hemiptera). Alginite solutions did not have contact insecticidal activity; the death of insects was caused mainly by the consumption of treated feed. At the same time, a high antifeedant effect was revealed from 45.0 to 85.0 % against adults and larvae of 2–3 instars of L. decemlineata and larvae of 2–3 instars of G. mellonella. To conclude, the application of alginite contributed to an increase in seed germination and plant productivity, and it did not reveal significant biological activity against insects.