The term arrested ear syndrome refers to the
abnormal development of the corn ear which
can be caused by a number of stress factors.
The most common theories proposed to explain
the occurrence of arrested ear is cold
stress, in particular a sudden drop in the average
temperature, and pre-tassel application of
crop protection chemical often including adjuvants.
It is important to note that the unpredictability
of arrested ear makes pinpointing
the exact cause very difficult despite numerous
studies done aimed at doing just this.
Arrested ear symptoms can occur on the ears,
husks, silks and leaves. At maturity ears affected
by this disorder are shorter, have less
kernels and have dried and stunted tips
(Figure 1 and 2). In trials done to simulate
arrested ear syndrome, symptoms could be
seen as soon as 7 days after foliar application
but was usually more pronounced at 21 days
after application. At this early stage it could be
observed that seed development at the tip of
the cob had prematurely stopped (Figure 3).sometimes turned a purplish colour due to the
build-up of sugars in the leaves.
Arrested ear syndrome is still very much an
unknown phenomenon but what is known is
that it can have a devastating effect on yield.
Avoiding the development of this disorder is of
great importance, and most research suggest
the risk of arrested ear developing can be
reduced by avoiding crop protection chemical
applications during growth stages V10 to VT.
It is important to note that if disease pressure
is high it can be very risky not to apply crop
protection products so if applications have to
be made in this period it is important not to
use adjuvants, especially Non-ionic surfactants,
and to avoid multi chemical mixes.
Research done at Purdue University shows
clearly that the more products get mixed in the
application the greater the arrested ear percentages
(figure 4). The full article can be see
ArrestedEars-1209.html