Tanja BOHINC, Filip VUČAJNK, Stanislav TRDAN
Zemdirbyste-Agriculture 2019, 106
From 2015–2016, different environmentally acceptable products for the control of harmful organisms, including the Colorado potato beetle (Leptinotarsa decemlineata), wireworms (Agriotes spp.), early blight (Alternaria solani) and late blight (Phytophthora infestans), were tested on potatoes. To control the Colorado potato beetle, was tested the efficacy of limestone dust at two concentrations, 345 and 690 kg ha-1. Brassica pellets (200 g m-2) and calcium cyanamide (1000 kg ha-1) were tested against wireworms. Tincture of propolis and propolis glycolic extract (mentioned as propolis) at 5 and 10 ml 1-1 H2O was tested against early and late blight. All of these products were combined into four treatments. Treatment 1 included treatments with limestone dust (690 kg ha-1), Brassica pellets and propolis (10 ml 1-1 H2O). Treatment 2 included treatments with limestone dust (345 kg ha-1), calcium cyanamide (1000 kg ha-1) and propolis (5 ml 1-1 H2O). Treatment 3 was positive control – use of registered phytopharmaceutical plant protection method, and treatment 4 was negative control (untreated plots). The inspection of all developmental stages: egg clusters, first and second instar larvae after hatching (L1–L2), and third and fourth instar larvae after hatching (L3–L4, adults), of the Colorado potato beetle was performed. After harvest, the tuber yield was evaluated. The evaluation of the yield was conducted on the small, medium and large tubers. The amount of damage caused by wireworms on the potato tubers was also detected in the different tubers. Calcium cyanamide was more effective than Brassica pellets against wireworms, whereas at a dose of 10 ml 1-1 H2O, propolis was proven to be a good alternative for the management of early and late blight under unfavourable weather conditions
for an epidemic outbreak. In 2016, the potato tuber yield in all three treatments was significantly higher than that in the untreated plots. With the combination of the tested products, promising alternative control strategies for future potato production systems might be obtained, which will be suitable for farming under changing climate conditions with a very narrow spectrum of registered phytopharmaceutical plant protection products.