21st February 2007
Mancozeb interchangeable with chlorothalonil at
critical T0 timing
With the mild winter and lush forward crops, the risk of
early disease in wheat is higher this year and a T0 treatment
of either mancozeb or chlorothalonil will be needed at Growth
Stage 30-31 in many situations, according to Dr. David Ellerton,
Technical Manager for Procam.
“A T0 treatment in cereals aims to take the pressure
off the T1 spray and delay the development of Septoria tritici.
This year it will be even more essential as crops have good
yield potential but are already suffering from high disease
levels. T0 sprays are applied at late tillering to GS 30,
which is normally mid to late March, with the T1 spray going
on at GS 32 when leaf 3 has emerged and which is normally
mid to late April. In some more advanced crops, growers
may be tempted to go earlier with their T0 spray, but you
have to consider the interval between T0 and T1 which if
it gets too wide will mean that leaf 3 is not adequately
protected. If the weather closes in and your T1 sprays are
delayed, you will get into trouble very quickly without
the insurance of a protectant T0 spray. Consequently I am
advising growers to stick to traditional timings. The use
of a multi-site contact protectant, such as Laminator (mancozeb)
or chlorothalonil alone or in mix depending on variety and
risk, will provide the necessary early protection required,”
says David.
“What is needed at T0 is a strong protectant fungicide
with activity on Septoria and rusts but with a different
mode of action to either strobs or triazoles. The multi-sited
protectants chlorothalonil and mancozeb are suitable products
and have been used widely and have performed well in the
UK and in France respectively. As T0 fungicides, they are
largely interchangeable but with possible supply problems
with generic chlorothalonils this spring, mancozeb could
prove to be an important alternative,” says Dr. Ellerton.
A simple low cost T0 application of Laminator or Quell Flo
will prevent disease infection recycling onto new foliage
as well as feeding the crop and so helping it maximise its
photosynthetic ability. “Mancozeb is a leading multi-site
compound which gives good contact protection against a number
of foliar diseases including Septoria tritici, mildew, yellow
and brown rusts. Its use also introduces an important anti-resistance
strategy into the crop. In my opinion, it can deliver just
as much as chlorothalonil can.” says Dr. David Stormonth,
Technical Manager, Interfarm (UK) Ltd.
A 1.5 l/ha dose of Laminator/Quell Flo delivers 683 gms
active ingredient of mancozeb per hectare, but it also delivers
140 g/ha of nutritional manganese and 13 g/ha of zinc which
will make leaves greener, leading to improved photosynthesis.
“There are many crops out there that are looking deficient
in manganese. The product is formulated as a flowable for
easy handling by cereal farmers and can be tank mixed with
a wide range of other relevant treatments such as growth
regulators, specific mildewicides or early spring herbicides.”
“Mancozeb offers simple multi-site chemistry which
protects and also helps feed the crop. It is one of the
lowest cost options available and will be a key component
in wheat fungicide programmes at T0 and T1 timings this
year when some competitor protectant products could be in
short supply,” concludes Dr. Stormonth.
Laminator/Quell Flo contains 455g/L mancozeb formulated
as a suspension concentrate. It is approved for use in wheat,
oilseed rape and potatoes. In cereals it is recommended
at a dose rate of 1.5 l/ha up to 3.3 l/ha. The maximum total
crop dose is 9.9 l/ha. It has a Harvest Interval of up to
GS 71 (grain watery ripe) and no LERAP. It is packed in
a 10 litre container.
For further comment and information, please contact Dr.
David Stormonth, Technical Manager, Interfarm (UK) Ltd.
on 01354 741414 or 07818 036506 (mobile).
