EFIKASNOST KOMBINACIJE MEZOTRIONA I TERBUTILAZINA IZ RAZLIČITIH PREPARATA U USEVU KUKURUZA

The aim of study was to test the efficacy and phytotoxicity of Calaris pro (326 g kg-1 terbuthylazine+50 g kg-1 mesotrione) and Twister (125 g kg-1 terbuthylazine+50 g kg-1 mesotrione) on weeds in maize crop. The experiment was set up during 2017 at the Kruščić, by a random block system in four repetitions. High efficacy of herbicides was manifested on Abutilon theophrasti, Amaranthus retroflexus, Ambrosia artemisiifolia, Chenopodium album, Chenopodium hybridum, Cirsium arvense, Datura stramonium, Solanum nigrum, Setaria glauca, Hibiscus trionum and Xanthium strumarium, while low efficacy was on Sorghum halepense. The total efficacy for product Calaris pro was 94,16% and for Tvister 96,20%.

The main weeds in the fields of the North-Eastern Ukraine

Goal. most of the herbologists rarely classify their weeds. Some types of weeds are sometimes given only epithets. But it is necessary to divide the weeds into larger groups, and the most important thing is to determine them by their quantitative indicators and not the qualitative epithets. Methods. Field, analytical. Results. For 45 years the experience of crops inspection was mainly carried out in the Kharkiv region. In these years of herbological monitoring perfect methods were carried out. Previously the following prevalence groups were established: very wide, wide, moderate, small, and very small. Later another “moderately broad” group was added. In the conditions of North-Eastern Ukraine the main survey of the arable land, which lasted for several decades, has established 270 species. The weeds grouped the floral list into six parts. The analyses of the group respectively: very wide, wide, moderately wide, moderately small and very small found that the number of species was 1.9, 1.9, 4.4, 6.7, 17.3 and 67.8 percent. With the expansion of the weed list, in the group of very small weeds the percentage of species grew. In recent years some adventitious weeds have appeared. These are: four types of Abutilon theophrast Ved., Hibiscus trionum L., Diqitaria ischaemum (Schreb.) Muehl) and Phytolacca americana (L.). Conclusions. On which territory it is necessary to determine the types of weeds and their criterion of prevalence and dominance. In the list weeds it is necessary to distinguish six groups: very wide, wide, moderately wide, moderate, small, very small. A significant part of the weeds on the list are included in the of the very small ones. In North-Eastern Ukraine, where there are 270 species observed, 67.8% of weeds belong to the last group.

Can morphology and chromosome number contribute to species delimitation? A case in the Hibiscus trionum complex (Tribe Hibisceae, Malvaceae)

A taxonomic revision of Hibiscus trionum from Egypt was undertaken using morphological and cytological studies of field collections and herbarium specimens. The data indicate that all specimens so far collected in Egypt belong to H. tridactylites, rather than H. trionum. This paper includes a comprehensive description of H. tridactylites, its occurrence, a comparison with other species in the H. trionum complex, and comments on habitat, along with images for easy identification. In addition, chromosome counts for this species from Egypt have been determined for the first time, which add to existing information on chromosome counts for the species from different regions of the world.

The vegetation of recently fallowed Masakwa fields in the Chad basin

On the clay plains surrounding Lake Chad (West Africa: northern Sudanian and southern Sahelian zone), certain varieties of pearl millet (Sorghum bicolor), commonly referred to as Masakwa, are cultivated during the dry season. Recently fallowed Masakwa fields support a particular progression of pioneer vegetation. In the first year of fallow, the pioneer vegetation typically belongs to the class Echinochloetea colonae Wittig 2005 and can be classified as Hygrophiletum auriculatae sensu lato. Approximately half of the stands consist of the Hygrophiletum auriculatae Ataholo 2002 sensu stricto, whereas the other half is primarily composed of a Celosia argentea-Hibiscus trionum community. After two years of fallow, the vegetation is typically formed by the Sorghetum arundinacei Ataholo 2002, which, in a few cases, can also occur in the first fallow year.

Use of Clearfield technology in the sunflower

Sunflower is one of the most important cultivated plants in Hungary. We carried out our research in 2009 with eight imidazolinone resistant hybrids and one conventional variety in order to compare the efficiency and selectivity of Clearfield technology to the conventional system. In the trial the Clearfield hybrids were treated by 3,5 l/ha Wing-P (pre) and 1,2 l/ha Pulsar 40 SL(post). The plot of the conventional variety was sprayed by 4,0 l/ha Wing-P and 0,5 l/ha Goal Duplo (pre).Wing-P also had a poor effect because of the lack of rain. Pulsar 40 SL gave an excellent result against the 2-6 leaves of monocotyledonous and the dicotyledonous weeds. Only the well-developed Hibiscus trionum survived the treatment. The combination of Wing-P and the Goal Duplo herbicide provided poor result against the caracteristical weeds of the experimental area because of the lack of rain. Oxifluorfen with contact effect burned the leaves of the sunflower.

Venice Mallow (Hibiscus trionum) Interference in Sugarbeet

Field studies were conducted in Powell, WY, in 2006 and 2007 to determine the influence of season-long interference of various Venice mallow densities and duration of interference on sugarbeet. Sucrose concentration was not affected by Venice mallow interference. The effect of Venice mallow density on sugarbeet root and sucrose yield loss was described by the rectangular hyperbola model. Root and sucrose yield loss increased as Venice mallow density increased. The estimated asymptote,A(percent yield loss as density approaches infinity) was 61% for both root and sucrose yield loss, and the estimated parameter,I(percent yield loss per unit weed density as density approaches zero) was 6% for both root and sucrose yield loss. Sugarbeet root yield decreased as the duration of Venice mallow interference increased. The critical timing of weed removal to avoid 5 and 10% root yield loss was 30 and 43 d after sugarbeet emergence, respectively. Results show that Venice mallow is competitive with sugarbeet implying that it should be managed appropriately to reduce negative effects on yield and prevent seed bank replenishment and re-infestation in subsequent years.