Choices aplenty for win­ter crop fungi­cides

Irish Independent - Farming - - Front Page -

The choice of fungi­cides avail­able is huge and this ar­ti­cle can­not cover all. Yet, the fol­low­ing will briefly out­line pos­si­ble fungi­cide choices for win­ter wheat and win­ter bar­ley.

Sep­to­ria is the main disease of win­ter wheat and the lat­est de­vel­op­ments are out­lined on page 13. Ta­ble 3 (see page 10) looks at the groups of fungi­cides and how they should be ap­plied to pre­vent in­sen­si­tive sep­to­ria build­ing up in the crop.

The main fungi­cide pro­gramme re­ally starts with the T1, which aims to pro­tect leaf 3 and leaf 2, both of which will con­trib­ute to fi­nal yield. Get the tim­ing of the T1 ap­pli­ca­tion wrong and you will strug­gle to con­trol disease all sea­son.

Ap­ply the T1 when the ma­jor­ity of leaf 3s are emerged. This is not nec­es­sar­ily at GS 31 or GS 32 but can be in be­tween.

The tar­get dis­eases at the T1 tim­ing in win­ter wheat are sep­to­ria, eyespot (in con­tin­u­ous tillage ground) and, to a lesser ex­tent, mildew. In­clude Chlorothalonil (Bravo) in all T1 ap­pli­ca­tions. Use a high rate (80pc+) of a tri­a­zole or tri­a­zole mix at the T1 tim­ing – Ven­ture Ex­tra, Gleam, To­cata or Pro­line can be used. Cheaper prod­ucts con­tain­ing epox­i­cona­zole could be used where eyespot is not set to be a prob­lem.

The T2 or sec­ond main fungi­cide tim­ing should be tar­geted at the flag leaf emerged. This will com­prise of a high-rate tri­a­zole ( 80pc+) + SDHI + chlorothalonil. This tim­ing gen­er­ally re­turns the most money, there­fore you should aim to spend the most money here. Tar­get the use of a prod­uct con­tain­ing a SDHI ( Avi­a­tor, Ven­ture Ex­tra) as these have shown a higher yield in tri­als when used at this tim­ing.

The fi­nal ap­pli­ca­tion (T3) will again con­sist of a tri­a­zole mix of prod­ucts ( Caramba, Foli­cur, Gleam, Prosaro, etc). These will give pro­tec­tion from fusar­ium (50pc con­trol is re­garded as good con­trol). The ad­di­tion of a stro­bil­urin may be jus­ti­fied in high-yield­ing sit­u­a­tions.

Start plan­ning bar­ley fungi­cide strate­gies early so that prod­ucts can be pur­chased on time and at a lower cost. Gen­er­ally, two fungi­cide ap­pli­ca­tions are needed to keep disease at bay.

Va­ri­eties with good disease re­sis­tance, such as Quench, Propino or Ma­galy, can lend them­selves to a low fungi­cide strat­egy, eg, re­duced rates at both tim­ings. Keep a close eye on Snakebite for rhyn­cho and Aza­lea and Cock­tail for net blotch at an early stage.

The first fungi­cide can be ap­plied from mid to late tiller­ing but is gen­er­ally ap­plied around the first node-de­tectable stage. Half rates are gen­er­ally suf­fi­cient. Prod­ucts such as Pro­line (pro­th­io­cona­zole), Punch C, Lyric, Stereo, etc, will all do an ex­cel­lent job at this stage.

Where rhyn­cho is a prob­lem early, use Pro­line at a higher rate (40-50pc of pro­th­io­cona­zole) as it has the best ac­tiv­ity of the prod­ucts men­tioned. In­clude a mildew­cide to help dry the le­sions. Like­wise, where net blotch is a prob­lem, use higher rates of Pro­line. The ad­di­tion of stro­bil­urins (Mo­dem, Galileo, etc) may also be jus­ti­fied.

The sec­ond fungi­cide ap­pli­ca­tion (T2) will co­in­cide with the flag leaf emerged to awns vis­i­ble. Tri­a­zoles form the cor­ner­stone of disease con­trol at the T2 tim­ing, with prod­ucts con­tain­ing pro­th­io­cona­zole fea­tur­ing strongly (Sil­tra, Fan­dango etc). Other al­ter­na­tives can be used, such as Ven­ture Ex­tra, Al­le­gro Plus, or tri­a­zoles plus stro­bil­urin mixes, such as Amis­tar Opti, Credo, etc.

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