Evaluation of Pre- and Postemergence Herbicide Combinations for Broadleaved Weeds in Sugar Beet

Lithuania sugar beet growers have few herbicide options available for weed management. Six field trials were conducted at the Institute of Agriculture, Lithuania, in order to evaluate the effects of chemical weed management in sugar beet. Treatments included untreated and hand-weeded control and several rates of phenmedipham plus desmedipham plus ethofumesate, phenmedipham, ethofumesate, triflusulfuron, chloridazon, and metamitron. Pre- and postemergence and only postemergence applications similarly affected weed control. Phenmedipham plus desmedipham plus ethofumesate was more effective for controlling weeds when applied in combination with metamitron, triflusulfuron, and chloridazon. The significantly lowest efficacy for weed control was phenmedipham combined with ethofumesate and metamitron as compared to the phenmedipham plus desmedipham plus ethofumesate. Reducing the doses of phenmedipham plusdesmedipham plus ethofumesate from 114+89+140 g a.i. ha-1 to 91+71+112 g a.i. ha-1 and 68+53+84 g a.i. ha-1 in mixture with triflusulfuron resulted in the increase of weed biomass. Full (45 g a.i. ha-1) and reduced doses (30 g a.i. ha-1) of triflusulfuron with phenmedipham plus desmedipham plus ethofumesate similarly affected weeds. The herbicides investigated did not have any negative influence on sugar beet productivity and quality

Measurements of Penetration and Detoxification of PS II Herbicides in Whole Leaves by a Fluorometric Method

The effect of herbicides that inhibit the photosynthetic electron transport at the photosystem II acceptor side has been analyzed in whole plants by using a fluorometric method. The data reported indicate that the apparent variable fluorescence of the induction curve normalized to the control value provides reliable information about the penetration rate and metabolic detoxification of PS II herbicides in whole plants

Field Evaluation of Herbicides on Small Fruit, Vegetable, and Ornamental Crops, 1997

Growers generally use herbicides to efficiently produce high-quality fruit and vegetables for processing or fresh market sales. Due to the smaller acreage of these crops compared to major field crops, fewer herbicides are registered for use in fruit and vegetable crops than for field crops. Each year, new herbicides are evaluated under Arkansas growing conditions with the objective of improving the herbicide technology for the grower, processor, and ultimately the consumer. This report includes studies on the control of many of the more serious weed problems in important crops of this region, including snapbeans, spinach, southern pea, watermelon, cantaloupe, tomato, blackberry, and grape. In addition, the report includes information on the tolerance of selected bedding plants to some effective herbicides

Određivanje fenmedifama i desmedifama u komercijalnom herbicidu tečnom hromatografijom pod visokim pritiskom

Betanal AM-11 is the herbicide that is using to control one-year old weeds with wide leafs in sugar beet fields. Active ingredients of the herbicide are phenmedipham and desmedipham. Commercial emulsifiable concentrate (EC) contains 80 g/L ( 10% of each active compound. We applied high performance liquid chromatography (HPLC) with diode array detector (DAD) at 254 nm for the determination of phenmedipham and desmedipham in commercial samples of Betanal AM-11. This method involves reversed-phase separation of the components on C-18 bonded silica with methanol-water (51+49, v/v) as the eluent. The procedure was highly selective and reproducible and can be successfully used in determining contents of phenmedipham and desmedipham on micro and macro levels.Betanal AM-11 je herbicid koji se koristi za suzbijanje jednogodišnjih širokolisnih korova na poljima sa šećernom repom. Aktivni sastojci herbicida su fenmedifam i desmedifam. Komercijalni koncentrat za emulziju (ES) sadrži 80 g/l ( 10% svake aktivne komponente. Za određivanje fenmedifama i desmedifama u komercijalnim uzorcima Betanala AM-11 je primenjena tečna hromatografija pod visokim pritiskom, DAD detektor i talasna dužina od 254 nm. Metod je obuhvatio razdvajanje komponenata na obrnutim fazama sa kolonom C-18 i eluentom metanol-voda (51+49, v/v). Postupak je veoma selektivan i reproduktivan i može se koristiti za određivanje makro- i mikro količina fenmedifama i desmedifama

Differential sensitivity of Atriplex patula and Chenopodium album to sugar beet herbicides : a possible cause for the upsurge of A. patula in sugar beet fields

In the last decade, the prevalence of Atriplex patula as a weed in the Belgian sugar beet area has increased. Possible reasons for its expansion in sugar beet fields, besides a poor implementation of the low-dose phenmedipham/activator/soil-acting herbicide (FAR) system, might be low sensitivity or evolved resistance to one or more herbicides used in sugar beet. Dose-response pot bioassays were conducted in the glasshouse to evaluate the effectiveness of five foliar-applied sugar beet herbicides (metamitron, phenmedipham, desmedipham, ethofumesate and triallate) and three pre-plant-incorporated herbicides (metamitron, lenacil, dimethenamid-P) for controlling five Belgian A.patula populations. Local metamitron-susceptible and metamitron-resistant populations of Chenopodium album were used as reference populations. Effective dosages and resistance indices were calculated. DNA sequence analysis of the photosystem II psbA gene was performed on putative resistant A.patula populations. Overall, A.patula exhibited large intraspecific variation in herbicide sensitivity. In general, A.patula populations were less susceptible to phenmedipham, desmedipham, ethofumesate and triallate relative to C.album populations. Two A.patula populations bear the leucine-218 to valine mutation on the chloroplast psbA gene conferring low level to high level cross-resistance to the photosystem II inhibitors phenmedipham, desmedipham, metamitron and lenacil. In order to avoid insufficient A.patula control and further spread, seedlings should preferentially be treated with FAR mixtures containing higher-than-standard doses of metamitron and phenmedipham/desmedipham and no later than the cotyledon stage

Fate of the organophosphate herbicide glyphosate in arable soils and its relationship to soil phosphorus status

Glyphosate is one of the world's most widely used herbicides. This study was undertaken to unravel the factors affecting its movement, sorption, persistence and leachability in different Finnish soils to create a sound basis for risk assessment. Field experiments indicated rather long persistence of glyphosate in Finnsih soils low in soil test P. The key soil factors promoting the persistence and reducing the leaching of glyphosate and its metabolite aminomethylphosphonic acid appeared to be low P status and high Al and Fe oxide contents in soil, leading to low degree of P saturation and to reduced biodegradability as result of strong sorption