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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 H 2 O 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 H 2 O). Treatment 2 included treatments with limestone dust (345 kg ha -1 ), calcium cyanamide (1000 kg ha -1 ) and propolis (5 ml 1 -1 H 2 O). 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 H 2 O, 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.

No abstract

In 2014 and 2015, we studied the effect of fungicide spraying with 11 different nozzles on the quality and quantity of head and leaf fungicide deposit, the percentage of Fusarium head blight (FHB) incidence, FHB index, the DON content, yield and grain quality parameters. The best quality and quantity of fungicide deposit on the front and rear head sides was achieved with the TeeJet Turbo FloodJet TF VP2 nozzle (FLOOD) and the Albuz AVI-TWIN 110-03 nozzle (AVI). In comparison with the majority of treatments, the FHB incidence and the FHB index was the highest on the unsprayed control. The FHB index was higher using the Lechler IDK 120-03 nozzle (IDK) than with the other nozzle types. In all the treatments, the DON content in the grain was less than 50 µg/kg. At this very low level of infection this is not surprising. The grain yield was the smallest on the unsprayed control. Better fungicide coverage of wheat heads with the FLOOD and AVI nozzles did not result in a statistically higher yield or better grain quality parameters. Negative correlations were confirmed between yield and variables as DON content, FHB incidence and FHB index and also between falling number and variables as fungicide coverage, FHB incidence and FHB index. Positive correlations were determined between DON content and FHB incidence, between hectolitre weight and variables as spray deposit and coverage and between protein content and variables as spray deposit and coverage.

The effect of spraying speed (5, 8.5 or 12 km/h) on deposition quality of fungicide on a winter wheat head, yield, grain quality, occurrence of Fusarium head blight (FHB) and deoxynivalenol (DON) content in grains was investigated in 2011 and 2012. Asymmetric double flat fan air-injector nozzles were used in the trial at a spraying pressure of 5.0 bars. A prothiconazole + tebuconazole fungicide mixture was used for spraying. An increase of spraying speed significantly lowered coverage values at the front and rear parts of a wheat head. At all three spraying speeds, the rear part of a wheat head reached a better coverage value. The effect of spraying speed was significant in 2011, when the 5 km/h spraying speed generated a significantly higher grain yield and a significantly higher thousand-grain weight in comparison with the other treatments. In both trial years, the lowest grain yield occurred on the unsprayed control. In 2011 and 2012, the latter also reached the lowest hectolitre weight and thousand-grain weight. In both trial years, the unsprayed control had a significantly higher DON content than the other treatments. In 2012, the DON content on the unsprayed control exceeded the allowed maximum level. The spraying speed did not affect the DON content in the grains. The effect of spraying speed was also noted in the FHB incidence. A significantly lower FHB incidence occurred at the 5 and 8.5 km/h spraying speeds.

IZVLEČEKSodobne hibridne sorte koruze že več desetletij prevladujejo tako v Sloveniji kot drugod po svetu. V Sloveniji je v pridelavi ohranjenih le malo starih populacijskih sort, 614 pa jih vzdržujemo v sklopu programa Slovenska rastlinska genska banka na Biotehniški fakulteti Univerze v Ljubljani. Izboljšanje populacijskih sort z rekurentno selekcijo je mogoče in ima lahko v primeru posebnih lastnosti svoje mesto v tržni pridelavi. V sortnih poskusih v osrednji Sloveniji in v Beli krajini smo proučevali izbrane stare populacije koruze. Pridelki koruze so bili na obeh lokacijah in v obeh letih močno odvisni od genotipa. Populacije 'Rdeča bohinjka' in delno 'Rumena bohinjka', podobno pa tudi 'LJ 180' so imele majhne pridelke, bile pa so med najbolj ranimi, medtem ko sta imeli sodobni hibridni sorti, 'P 9074' in 'Ronaldinio KWS', pričakovano največji pridelek. Pridelek populacije 'P 9074' je bil na laboratorijskem polju Biotehniške fakultete skoraj dvakrat večji od druge najboljše populacije poltrdinke 'Metliška Plut'. Prav ta populacija pa se je v vseh štirih poskusih pokazala kot zelo primerna za nadaljno vzdrževanje in prijavo sorte, saj bi lahko v manj intenzivni pridelavi pomenila ustrezno alternativo hibridnim sortam.Ključne besede: pridelek koruze; starejše akcesije; genska banka; populacijske sorte ABSTRACT EVALUATION OF MAIZE CROPS FOR SUSTAINABLE FARMINGModern hybrid maize varieties dominated for several decades both in Slovenia and elsewhere in the world. The production is maintained only of few landrace populations, but some are maintained at Slovenian Gene Bank. Improvement of local varieties is possible by recurrent selection and may in the case of their specific characteristics deserve their cultivation for specific purposes. Presented experiments have been conducted to characterize selected old Slovenian accessions in two regions -in central Slovenia and in Bela Krajina. Yields of corn at both locations and both years were significantly depending on the genotype. 'Rdeča Bohinjka' and partially 'Rumena Bohinjka' and, similarly, the 'LJ 180' had a predominantly low yields but were also the earliest, while modern hybrid variety 'P 9074' and 'Ronaldinio KWS ' had the expected highest yield. Yield of 'P 9074' grown at the Laboratory field of the Biotechnical Faculty was almost twice higher than the second best accession 'Metliška Plut'. However it is this semi-flint accessions 'Metliška Plut' that proved very suitable at all four experiments and is recommended for further maintenance and varietal testing as it can serve as appropriate alternative in a less intensive production.

Spraying parameters are important factors when spraying wheat heads against fusarium head blight (FHB) to control the deoxynivalenol level in the grain and to obtain high and quality yields. In 2019 and 2020, field trials were conducted in order to establish the effect of the spraying pressure (2 bar, 4 bar, and 6 bar) of special nozzles with a variable flow rate Agrotop VR 1.5 on the head fungicide coverage, yield parameters, and the deoxynivalenol (DON) value in the grain. The coverage of the front and rear sides of wheat heads increased with the increase of spraying pressure from 2 to 6 bar. In 2019, when the infection with FHB was more severe, no significant differences appeared in the yield and the hectoliter weight at a lower spraying pressure, while the DON value at this pressure approached the maximum permissible level. In that year, the DON value exponentially fell with the increase of spraying pressure. In 2019, the thousand grain weight was higher at the spraying pressure of 6 bar than at the pressures of 2 and 4 bar. The results show that also a lower spraying pressure (2 bar) and a volume application rate (117 L/ha) below the recommended one suffice to retain the DON value in the grain below the maximum permissible level, even in years with more severe infection.

The aim of our experiment was to improve fungicide spray deposition and coverage of potato leaves by using air-injector nozzle types. We used two standard nozzle types-a flat fan nozzle ST and a hollow cone nozzle TR, as well as a couple of air-injector nozzle types-an air-injector compact nozzle IDK and a symmetric double flat fan air-injector nozzle TWIN (with a 30 ° forward and a 30 ° backward spray jet angle). Water-sensitive paper was placed on the upper, middle and lower part of the plant in order to determine the quality of fungicide deposition and the ability of droplets to penetrate lower parts of the plant. When using the air-injector compact nozzle IDK, potato leaves were covered well at all three levels of the plant. The use of the above-mentioned nozzle resulted in the lowest reduction in coverage value and droplet impression area from the top towards the lowest part of the plant. Furthermore, the nozzle created large enough droplets with sufficient mass and speed to penetrate the dense canopy all the way to the lowest part of the plant. When using the symmetric double flat fan air-injector nozzle TWIN, the angle of both spray jets was excessively wide in order for the droplets to reach the lower part of the plant despite a very large droplet impression area. The use of both standard nozzle types resulted in a poor spray mixture coverage of the middle and lower part of the plant. This predominantly occurred due to insufficient droplet size and the subsequent lack of kinetic energy. Results show that the use of a newer air-injector compact nozzle IDK improves the deposition and coverage of potato leaves with spray mixture.