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Arrested ear syndrome of Maize

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The term arrested ear syndrome refers to theabnormal development of the corn ear whichcan be caused by a number of stress factors.The most common theories proposed to explainthe occurrence of arrested ear is coldstress, in particular a sudden drop in the averagetemperature, and pre-tassel application ofcrop protection chemical often including adjuvants.It is important to note that the unpredictabilityof arrested ear makes pinpointingthe exact cause very difficult despite numerousstudies done aimed at doing just this.  Arrested ear symptoms can occur on the ears,husks, silks and leaves. At maturity ears affectedby this disorder are shorter, have lesskernels and have dried and stunted tips(Figure 1 and 2). In trials done to simulatearrested ear syndrome, symptoms could beseen as soon as 7 days after foliar applicationbut was usually more pronounced at 21 daysafter application. At this early stage it could beobserved that seed development at the tip ofthe cob had prematurely stopped (Figure 3).sometimes turned a purplish colour due to thebuild-up of sugars in the leaves. Arrested ear syndrome is still very much anunknown phenomenon but what is known isthat it can have a devastating effect on yield.Avoiding the development of this disorder is ofgreat importance, and most research suggestthe risk of arrested ear developing can bereduced by avoiding crop protection chemicalapplications during growth stages V10 to VT.It is important to note that if disease pressureis high it can be very risky not to apply cropprotection products so if applications have tobe made in this period it is important not touse adjuvants, especially Non-ionic surfactants,and to avoid multi chemical mixes. Research done at Purdue University showsclearly that the more products get mixed in theapplication the greater the arrested ear percentages(figure 4). The full article can be seeat: http://www.kingcorn.org/news/articles.08/ArrestedEars-1209.html