Plants as Bio-Insecticides in the Service of the Suppression of Potato Tuber Moth in Storage

Phthorimaea operculella Zeller (Lepidoptera: Gelechiidae), is economically very important pest of potato and other solanaceous plants in the field and warehouse. Frequent and excessive use of insecticides leads to development of insects resistance, environmental pollution, and lives residues in food. All this implicated as a obligatory applications of botanical insecticides. Research in this area is increasingly attracting attention as the kingdom of plants is an inexhaustible source of active ingredients with insecticidal properties. This is the only way in the registration and appropriate use of eco-friendly active ingredients as pesticides

Sadržaj polifenola i antioksidativni kapacitet ekstrakata listova paradajza zaraženih plamenjačom

Late bligth is one of the main causes of the tomato yeild losses. In this paper, the biochemical response of tomato variety Plovdivski kasni in leaves infected with Phytopththora infestans was analyzed. It was found that there is a correlation between the degree of disease severity and the content of total polyphenols and flavonoids in the leaves. The different content of phenolic compounds also affected the antioxidant capacity of leaf extracts. By increasing the degree of infection, the content of the soluble polyphenolic compounds and the antioxidant capacity of the leaves decreased.Plamenjača je jedan od glavnih uzroka smanjenja prinosa paradajza što može dovesti do velikih ekonomskih gubitaka. U ovom radu je ispitan biohemijski odgovor listova paradajza sorte ‘Plovdivski kasni’ na infekciju prouzrokovačem plamenjače Phytopththora infestans. Utvrđeno je da postoji korelacija između stepena zaraženosti biljke i sadržaja ukupnih polifenola i flavonoida u listovima. Različit sadržaj fenolnih jedinjenja je uticao i na antioksidativni kapacitet ekstrakata listova. Povećanjem stepena infekcije sadržaj rastvorljivih polifenolnih jedinjenja i antioksidativni kapacitet listova se smanjivao

Performance of hydroponically cultivated geranium and common verbena under salinity and high electrical conductivity levels

Abiotic factors in nutrient solutions (NSs), such as salinity and high electrical conductivity (EC), may adversely alter plant growth and crop performance. However, there are medici-nal/aromatic plants which can not only withstand these adverse conditions, but which can also increase their productivity or even enhance their quality in such conditions. As fresh water sources suitable for irrigation are becoming more and more limited, the use of low-quality water sources and hydroponic growing systems have been suggested as the main alternatives. Towards that direction, this study aims to evaluate the effect of high EC levels in NSs on geranium (Pelargonium graveolens L’Hér.) and common verbena (Verbena officinallis L.) plants cultivated in a soilless (perlite) hydroponics system. Plants were irrigated with a full nutrient solution of EC 2.1 dS m−1 and pH 5.8 until they reached a uniform size. Then, three treatments were applied, namely: (a) a control treatment with an EC of 2.1 dS m−1 in the NS, (b) a high-salinity NS created by adding 75 mM of NaCl (EC under 8.5 dS m−1) and (c) a concentrated NS with an EC of 8.5 dS m−1. In pelargonium, high salinity decreased the total phenolic and total flavonoid contents; antioxidant capacity; N, K, Mg and P content; as well as chlorophyll fluorescence, compared to the control treatment. On the other hand, increased salinity levels increased the Na and Ca content and stomatal resistance. In common verbena, salinity decreased total phenolic content and chlorophyll fluorescence but increased total flavonoid content; antioxidants; leaf K, P, Na, Cu and Zn content; and stomatal resistance, compared to the control. In both species, high EC did not affect polyphenols, flavonoids or antioxidants, whereas it increased stomatal resistance and nutrient accumulation in the leaves, and decreased chlorophyll fluorescence compared to the control treatment. Damage indices, indicated by lipid peroxidation, hydrogen peroxide production and the elevation of enzymes’ antioxidant activities, were evidenced in both saline-and high-EC-treated plants. In conclusion, despite having the same EC levels in the nutrient solution, it seems that ionic stress caused by high mineral concentrations in the nutrient solution had less severe effects on the tested plants than the relevant osmotic stress caused by high salinity due to the addition of NaCl in the nutrient solution

Influence of non - chemical weed control methods on sugar beet productivity and quality parameters

Weed control in organic farming conditions is complicated and requires extra expenses. There are many different non-chemical weed control methods but some of them are not effective enough. For this reason, a long-term stationary field experiment was carried out at the Experimental Station of Aleksandras Stulginskis University (ASU) in 2017-2018. The following sustainable weed control systems were tested: 1) inter-row loosening (control treatment); 2) inter-row cutting and mulching with weeds; 3) inter-row cutting and mulching with Persian clover; 4) inter-row cutting and mulching with white mustards; 5) inter-row cutting and mulching with spring barley. The fertility of sugar beets was determined by weighing clean roots. Their roots ramification was determined by counting all the branched beets in the sample. Amounts of Na, K, a-amino N and sugar content were determined in the laboratory of Kedainiai sugar factory (the stock company "Nordic Sugar Lietuva"). To determine the photosynthetic parameters, the sugar beet leaves were scanned by the Delta T Scan scanner, taking 3 leaves from each experimental plot. Sugar beet processing parameters, namely, sugar content in molasses, sugar output and white sugar yield were calculated according to standard formulas. The alternatives of weed control often reduced the yields of sugar beet substantially; however, when mulching with white mustard, the decrease in fertility was not essential. In most cases, non-chemical weed control measures had insignificant effect on the parameters of sugar beet quality: the content of Na, K and a-amino N. The most significant sugar output (16.34% and 16.26%) was found in sugar beet roots, which were grown applying inter-row mulch of spring barley and weed (P <0.05). Comparing non-chemical weed control systems, the highest amount of white (crystalline) sugar (4.96 t ha"1) was derived from the sugar beet that was grown using white mustard mulchVytauto Didžiojo universitetasŽemės ūkio akademij