Selectivity and efficacy of thifensulfuron-methyl with adjuvant and without in control of broadleaf weeds in winter wheat

The research was conducted in 2020-2021, in 3 different locations (Constanța, Călărași and Teleorman) and aimed to evaluate the biological activity of the herbicide Thifensulfuron-methyl 75% WG with adjuvant and without in control of broadleaf weeds in winter wheat. The experiments were placed in randomized blocks, in 4 repetitions with a plot area of 100 m2 . The floristic composition of the winter wheat fields studied has been diversified, being present: Amaranthus retroflexus, Capsella bursa – pastoris, Centaurea cyanus, Chenopodium album, Erigeron annuus, Fumaria officinalis, Galium aparine, Lamium spp., Papaver rhoeas, Polygonum convolvulus, Sinapis arvensis, Stellaria media, Veronica spp., Viola arvensis etc. Herbicides were applied in post-emergence when weeds were in the early stages of growth and development. The herbicide Thifensulfuron-methyl 75% WG with adjuvant and without was applied at the doses of 20, 30 and 40 g/ha. The adjuvant (Trend 90 EC) was applied at 250 ml/ha. The assessments made at 10, 20 and 30 days after treatments focused the density of weeds, the percentage of soil cover, selectivity and the effectiveness compared to the untreated control. The results obtained showed that the efficacy depends on the dose applied, the type of weeds and their density on square meter. The Thifensulfuron-methyl 75% WG ensured a good efficacy in controlling of broadleaf weeds in winter wheat, the best results being obtained at the higher dose and when it was applied together with Trend 90 EC. Some weed species were insufficiently controlled at the dose of 20 g/ha: shepherd's purse, cleavers, blackbindweed, lamb's quarters etc

RESEARCH ON THE EFFECTIVENESS OF FUNGICIDES MIXTURES IN CONTROL OF CEREAL DISEASES

Romania is one of the most important European cereal producing countries. Foliar and ear diseases are a permanent risk factor for the quantity and quality of crops. In order to obtain increasing harvests, the control of diseases is implemented since spring by preventive and curative methods, one of the most efficient being the controlled and optimal use of fungicides. Fungicide resistance has been recognized as a factor affecting the control of cereal diseases. In order to reduce the risk of resistance developing in the target pathogens FRAC (Fungicide Resistance Action Committee) recommends the use of fungicide mixtures. In this context, this study presents research on the efficacy in combating wheat and barley diseases of two mixtures of fungicides (Prothioconazole 16% + Spiroxamine 30% and Trifloxystrobin 15% + Prothiconazole 17.5%) applied at different doses and phenophases of plants and phytopathogens. The experimental plots were placed in 2 different locations (Dâlga-Călărași - non-irrigated and Agigea-Constanța - irrigated), in randomized blocks, in 4 repetitions with a plot area of 30 m2. The mixture of Prothioconazole 16% + Spiroxamine 30% EC was applied at a dose of 0.8, 1.0 and 1.25 l/ha and the mixture of Trifloxystrobin 15% + Prothiconazole 17.5% SC was applied at a dose of 0.5, 0.75 and 1.0 l/ha. The two treatments were applied between BBCH 30-61 from the end of the twinning phenophase to the beginning of flowering, with an interval of 14 days between treatments. The assessments were made before the application of treatments at 15 and 30 days after application and focused on efficacy in control and selectivity to crop plants. The obtained results demonstrated a good efficacy of the two mixtures of fungicides in controlling cereal crops against the complex of foliar and ear diseases (Fusarium, Septoria, Puccinia, Rhynchosporium, Helminthosporium)

EFFICACY AND SELECTIVITY OF DIFFERENT FORMULATIONS OF PENDIMETHALIN ON WEED CONTROL IN MAIZE

Due to its use in human food, livestock feed and as a raw material in industry, maize is one of the most important crops, both globally and nationally. Romania is one of the European leaders in corn cultivation, being ranked second in EU in 2020. The high degree of weed infestation of croplands requires the use of herbicides applied in an integrated weed control management. Due to the slow growth in the first 4-6 weeks, maize is very sensitive to weed infestation, and due to the low density per square meter, a strong competition in favor of weeds is created from the beginning. In this context, the paper presents data on the efficacy and selectivity of 3 different pendimethalin formulations (EC, SC, CS) applied in pre-emergence and in early post-emergence stage, when maize was at BBCH 13 (3 leaves unfolded). out in 2019 in Romania at Didactic Farm Moara Domnească, Ilfov county. on a brown reddish The herbicide Pendimethalin 33% EC was applied at 3.0, 4.0 and 5.0 l/ha, Pendimethalin 40% SC at 2.0, 3.0 and 4.0 l/ha and Pendimethaline 45.5% CS at 2.0, 2.5 and 3.5 l/ha. In experimental field the predominant weeds were annual monocotyledonous and dicotyledonous: Echinochloa crus-galli (L.) Beauv., Digitaria sanguinalis (L.) Scop., Setaria sp. (L.) Beauv., Chenopodium album (L.), Amaranthus retroflexus (L.), Ambrosia artemisiifolia (L.) and Xanthium orientale subsp. italicum (Moretti) Greuter. Assessments made at 10, 28 and 42 days after treatments demonstrated a good efficacy of the different formulations of herbicide Pendimethalin in control of annual weeds in maize, the best results were obtained at the higher rates. No phytotoxicity symptoms have been shown in the trial

PROBLEM WEEDS CONTROL IN STRAWBERRY CROPS IN DIFFERENT GROWING SYSTEMS IN ROMANIA

Irrespective of the growing system practiced, strawberry plants are very susceptible to weed competition, especially in the beginning stage after planting, when they are small and frequent irrigations provide perfect conditions for the weed seeds germination. Weeds emerged inside the cannopies, in perennial crops, negatively influence the longevity of the plantations by weakening the plants or even suffocating them, consuming water and nutrients, favoring the infection with diseases and pests, negatively influencing the ripening of the fruits. The research aimed the identification of problem weeds and measures to combat them in 3 different systems of perennial strawberry crops grown under field conditions. The research and assessments were carried out in Giurgiu County at Hotarele in the strawberry crop cultivated with plastic film in rows and straws substrate between the rows, in the village of Oinacu in the strawberry crop with plastic film in rows and in the experimental field at RDIPP - Bucharest where the strawberry was grown without film and without straws substrate between the rows. Two determinations were made on each row of strawberries in the period 2021-2022, using a metric frame and the observations concerned the density (number of plants/m2), the participation (% in which each species participates in the general weeding), the frequency (% where each species was noticed at the observation points), family, class (monocotyledonous, dicotyledonous) and living period of each species. The growing system with plastic film on rows and with a layer of straws between rows ensured the best protection of the strawberry crop against the weeds competition, on condition that after harvesting the weeds that sprout through the holes of the film, on the interval between rows and around the strawberry field, to be destroyed

RESEARCH REGARDING PROBLEM WEEDS IN POTATO CROP IN SOUTHERN ROMANIA

Potato (Solanum tuberosum L.) is considered to be one of the most competed crop by weeds. They may cause great losses, reducing the yield by 20-35%, consume large amounts of water and nutrients, decrease the effectiveness of treatments against diseases and pests and mechanized harvesting becomes difficult or impossible. The observations and assessments carried out aimed at deciding the problem weeds in the potato crop against which prevention and control measures must be effectively applied. The research targeted the monitoring and mapping of weeds in potato crops in Dâmbovița, Prahova and Călărași counties, in Romania. 30 determinations per hectare were conducted during 2020-2021, using the metric frame and the observations focused on density (number of plants/m2), participation (% in which each species is involved in the whole weed infestation), frequency (% in which each species was found in the observation points), class (pteridophytes, monocotyledonous, dicotyledonous) and the life span of each species (ephemeral, annual, biennial, weeds that can overwinter, perennials). The results obtained marked that the problem weeds in potato crops are usually perennial species difficult to control. Thus, among the dicotyledonous weeds, the species of Cirsium arvense, Sonchus arvensis and Convolvulus arvensis were identified as problem weeds, and among the monocotyledonous weeds, Sorghum halepense and Agropyron repens. Also in Lungulețu, due to the monoculture, the species Equisetum arvense, Ambrosia artemisiifolia and Symphitum officinalis created special problems for control, in Călărași county at Dâlga Cannabis ruderalis and in Prahova, Polygonum convolvulus and the Xanthium species. Even annual species, when they find favorable conditions for growth and development, are causing troubles: Chenopodium album, Polygonum aviculare, Echinochloa crus-galli. It has also been noted the increasing presence of invasive species: Ambrosia, Erigeron, Veronica, Xanthium

BIOLOGICAL EFFICACY AND SELECTIVITY OF FLUROXYPYR AND FLORASULAM IN CONTROL OF BROADLEAF WEEDS IN WINTER BARLEY

During 2021-2022 two fields trial with the winter barley variety “Lucian” was conducted. The studys was conducted in 2 different locations (Constanța and Călărași) and aimed to evaluate the biological activity of two herbicides based Fluroxypyr and Florasulam in control of broadleaf weeds in winter barley crops. The experiments were placed in randomized blocks, in 4 repetitions with a plot area of 100 m2. Efficacy and selectivity of the herbicides Flurostar Super SE (100 g/l fluroxypyr +1 g/l florasulam) and Tomigan XL 102.5 SE (100 g/l fluroxypyr + 2.5 g/l florasulam), applied at registered and higher rates, was evaluated. The herbicide application was done at the phenophase of the crop – 1st – 2nd stem node (ВВСН 30-32). The efficacy of the products by the 10 score scale of EWRS was recorded. The results were compared with untreated controls. The herbicide selectivity for the winter barley by the 9 score scale for phytotoxicity of EWRS was reported. The results obtained showed that the efficacy depends on the dose applied, the type of weeds and their density on square meter. The herbicide based floroxypyr and florasulam ensured a good efficacy in controlling of broadleaf weeds in winter barley, the best results being obtained at the higher dose. For both herbicides (Flurostar Super and Tomigan XL) at all evaluated rates signs of phytotoxicity for the crop were not observed