Thiencarbazone-methyl (TCM) and Cyprosulfamide (CSA) – a new herbicide and a new safener for use in corn

Thiencarbazone-methyl is a new herbicide for the selective control of grasses and broadleaf weeds primarily in corn. The active ingredient belongs to the chemical class of sulfonly-amino-carbonyl-triazolinones (SACT) and acts as an inhibitor of the ALS-enzyme. The compound offers cross spectrum activity against grasses and broadleaf weeds and can be applied at the pre-emergence and the post-emergence timing. The use rate depends on the application timing and may vary from 22 – 45 g a.i./ha in pre-emergence applications and 10 – 15 g a.i./ha in post-emergence applications. Sequential treatments are possible as long as the maximum seasonal dose of 45 g a.i./ha is not exceeded. In commercial corn herbicides, TCM is always combined with safener technology such as the novel safener cyprosulfamide and with other herbicidal active ingredients. In pre-emergence applications, the primary herbicidal mixpartner is isoxaflutole. In herbicides designed for postemergence use, TCM is co-formulated with foramsulfuron, iodosulfuron or tembotrione. The commercial herbicides composed of TCM and CSA plus sulfonylurea or triketone partners have demonstrated high weed control success in conventional and herbicide-tolerant corn production systems. Depending on the product, the potential for one pass weed control has been confirmed. Control of perennial grasses like Sorghum halapense and Elymus repens together with control of problem weeds like Polygonum convolvulus and suppression of Cirsium arvense and Convolvulus arvensis appear to be among the most attractive features of TCM-based herbicides under European conditions. High crop tolerance of herbicides combining two or three highly active ingredients in one commercial product is ensured by the novel safener cyprosulfamide which can protect corn via root uptake and via leaf uptake from herbicide damage. Keywords: Herbicide, pre-emergence, post-emergence, residual activity, sulfonylaminocarbonyl-triazolinone, weed controlThiencarbazone-methyl (TCM) und Cyprosulfamide (CSA) – ein neues Herbizid und ein neuer Safener zur Anwendung in MaisThiencarbazone-methyl ist ein neues Herbizid zur selektiven Bekämpfung von Ungräsern und dikotylen Unkräutern vor allem in Mais. Der Wirkstoff gehört zur Klasse der Sulfonylaminocarbonyltriazolinone (SACT) und wirkt als ALS-Hemmer. Der Wirkstoff besitzt ein breites Wirkungsspektrum und kann im Vorauflauf oder im Nachauflauf angewandt werden. Die empfohlene Dosis hängt vom Anwendungszeitpunkt ab und liegt zwischen 22 – 45 g a.i./ha im Vorauflauf und bei 10 – 15 g a.i./ha in Nachauflauf. Spritzfolgen sind möglich, solange die Maximaldosis von 45 g a.i./ha nicht überschritten wird. In kommerziellen Maisherbiziden wird TCM immer mit einem Safener, meist mit Cyprosulfamide, und weiteren herbiziden Wirkstoffen kombiniert. Für Vorauflaufanwendungen ist Isoxaflutole der primäre Mischpartner. In Nachauflaufherbiziden wird TCM gemeinsam mit Foramsulfuron, Iodosulfuron oder Tembotrione formuliert. Die Herbizidkombinationen aus TCM + CSA und Sulfonylharnstoff- oder Triketonpartner haben ihren Nutzen für die Unkrautbekämpfung in konventionellen und herbizid-toleranten Maisproduktionssystemen unter Beweis gestellt. Eine einmalige Anwendung der am breitesten wirkenden Produkte kann die Unkrautbekämpfung für eine gesamte Anbausaison sichern. Besonderen Wert der TCM-haltigen Produkte hat die Wirkung gegen perennierende Gräser wie Sorghum halapense und Elymus repens, die gekoppelt ist mit der Bekämpfung des Problemunkrauts Polygonum convolvulus und der unterdrückenden Wirkung gegen Cirsium arvense und Convolvulus arvensis unter europäischen Bedingungen. Die sichere Verträglichkeit der Kombiherbizide, die zwei oder drei herbizide Wirkstoffe enthalten, wird durch den neuen Safener Cyprosulfamide gewährleistet, der den Mais nach der Aufnahme durch Wurzeln und Blätter vor Herbizidschäden schützt. Stichwörter: Dauerwirkung, Herbizid, Nachauflauf, Sulfonylaminocarbonyltriazolinone, Unkrautbekämpfung, Vorauflau

Crop Response to Leaf and Seed Applications of the Biostimulant ComCat® under Stress Conditions

Although clear evidence for benefits in crop production is partly missing, several natural compounds and microorganisms have been introduced to the market as biostimulants. They are supposed to enhance nutrient efficiency and availability in the rhizosphere, reduce abiotic stress, and improve crop quality parameters. Biostimulants often derive from natural compounds, such as microorganisms, algae, and plant extracts. In this study, the commercial plant extract-based biostimulant ComCat® was tested in two field experiments with maize in the communities of Banikoara and Matéri in Northern Benin and six pot experiments (four with maize and two with winter barley) at the University of Hohenheim in Germany. Maize was grown under nutrient deficiency, drought, and weed competition, and winter barley was stressed by the herbicide Luximo (cinmethylin). ComCat® was applied at half, full, and double the recommended field rate (50, 100, and 200 g ha−1) on the stressed and unstressed control plants as leaf or seed treatment. The experiments were conducted in randomized complete block designs with four replications. The above-ground biomass and yield data of one experiment in Benin were collected. The biostimulant did not promote maize and winter barley biomass production of the unstressed plants. When exposed to stress, ComCat® resulted only in one out of eight experiments in higher barley biomass compared to the stressed treatment without ComCat® application. There was a reduced phytotoxic effect of cinmethylin after seed treatment with ComCat®. Crop response to ComCat® was independent of the application rate. Basic and applied studies are needed to investigate the response of crops to biostimulants and their mechanisms of action in the plants before they should be used in practical farming