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Permit, containing the active ingredient halosulfuron (750 g/kg WG) is a new herbicide in maize. It is listed in Annex I since October 2013. Permit plays a special role when dealing with the hard to control weed yellow nutsedge (Cyperus esculentus). Yellow nutsedge is an invasive plant belonging to the family Cyperaceae (sedges). Specific graminicides used to control Poaceae (sweet grasses) are not effective against Cyperacea. Propagation is rapid and occurs exclusively via tubers formed in the soil. Affected areas in Germany grow rapidly, especially in Lower-Saxony. Application rates from 30-50 g/ha Permit were tested in solo or split application in 7 trials to control Cyperus esculentus in maize. Application timing proved critical for successful control. High levels of control were achieved with 30-50 g/ha Permit with single applications at BBCH 16 (efficacy 94-98%) as well as with split applications at BBCH 14 and 16 of the crop (efficacy 94-99%). Because yellow nutsedge often emerges in multiple waves, the split application provides more reliable control. Permit offers new opportunities to effectively control Cyperus esculentus in maize and thus closes an important gap in the weed spectrum of currently available maize herbicides.

Yellow Nutsedge (Cyperus esculentus L.) belongs to the family of Cyperaceae. It propagates exclusively with tubers in the ground. Its abundance has strongly increased in Switzerland in the last two decades. Main reasons for this increase are changing land use and production systems, a difficult herbicide control and a low awareness level among the farmers. The actual invasion is enhanced by unintended dislocation of tubers by machines or crops/crop waste, lack of knowledge of infested fields and missing supporting measures. An obligation to announce infested fields and to control Yellow Nutsedge is currently discussed in Switzerland. Such an obligation would help contractors and buyers of crops to reduce unintended dislocation of tubers. Cleaning up infested plots is quickly expensive and complex. Maleic acid hydrazide is actually used for preventing potato tubers to germinate in stock. We tested Fazor (maleic acid hydrazide) and Asulox (asulam) for its efficacy on preventing germination of Yellow Nutsedge tubers. The results of our pot trial in the greenhouse are clear. The expected efficiency was not observed. Furthermore the complexity of problems with this species in agriculture is discussed and some ideas for a control strategy are given in this paper.

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Some closely related members of the monocotyledonous families Alismataceae, Liliaceae, Juncaceae, Cyperaceae, Poaceae and Araceae with variable modes of pollination (insect- and wind-pollination) were studied in relation to the ultrastructure of pollenkitt and exine (amount, consistency and distribution of pollenkitt on the surface of pollen grains). The character syndromes of pollen cementing in entomophilous, anemophilous and intermediate ('ambophilous' or 'amphiphilous') monocotyledons are the same in principal as in dicotyledons. Comparing present with former results one can summarize: 1) The pollenkitt is always produced in the same manner by the anther tapetum in all angiosperm sub-classes. 2) The variable stickiness of entomophilous and anemophilous pollen always depends on the particular distribution and consistency of the pollenkitt, but not its amount on the pollen surface. 3) The mostly 'dry' and powdery pollen of anemophilous plants always contains a variable amount of 'inactive' pollenkitt in its exine cavities. 4) A step-by step change of the pollen cementing syndrome can be observed from entomophily towards anemophily. 5) From the omnipresence of pollenkitt in all wind-pollinated angiosperms studied one can conclude that the ancestors of anemophilous angiosperms probably have been zoophilous (i.e. entomophilous) throughout. [ABSTRACT FROM AUTHOR]