Wheat Tan Spot Control Recommendations

Fungicide Common Name	Fungicide Trade Name	Formulated Rate/Acre
azoxystrobinc	Quadris	6.2 - 10.8 fl oz
mancozeba	Dithane M45	2.0 lbs
mancozeba	Dithane F45	1.6 qts
mancozeba	Dithane DF	2.0 lbs
mancozeba	Manzate 200	2.0 lbs
mancozeba	Manzate DF	2.0 lbs
mancozeba	Penncozeb	2.0 lbs
mancozeba	Penncozeb DF	1.5 - 2.0 lbs
propiconazoleb	Tilt 3.6EC	4.0 fl oz
propoiconazole + trifloxystrobinb	Stratego 250 EC	10.0 fl oz
pyraclostrobind	Headline 2.09EC	6.0 - 9.0 fl oz

Other Control Recommendations:   Management Practices

Remarks:

a: These fungicides are protestant types that must be applied before infection to provide a barrier to prevent infection. Make first application when flag leaf is fully emerged (Feekes' stage 10 or Zadoks' 45) and repeat when grain head is visible about 10-12 days later. Do not make last application within 26 days of harvest. Livestock may not graze in treated areas within 26 days of last treatment. Penncozab is only registered for use on wheat.

b: Scout fields weekly from Zadoks' growth stages (GS) 30 through 59 (Feekes' GS 5 through GS 10.5) head emergence. For leaf and plume blotch collect main tillers from 10 plants from 10 randomly selected areas within the field. Examine the appropriate indicator leaf (see Figure 3) from each tiller and record the number of indicator leaves with one or more lesions. If 25% of the 100 indicator leaves have one or more lesions, then a fungicide application is indicated.

c: Quadris should be integrated into an overall disease management strategy that includes proper selection of varieties with disease tolerance, proper timing and placement of irrigation, removal of plant debris in which inoculum overwinters, plant residue management, and crop rotation. Resistance management: Do not make more than two applications of Quadris per acre per year. Application directions: Quadris should be applied prior to or in the early stages of disease development. Applications may be made at any time, immediately after jointing (Feeks 6 or Zadok's 31) up to late head emergence (Feekes 10.5 or Zadok's 59). A crop oil concentrate adjuvant may be added at 1.0% V/V to optimize efficacy. Do not apply later than Feekes growth stage 10.5 (Zadok's 59). Do not harvest treated wheat for forage. Do not apply more than 0.77 quarts product/acre/season (0.4 lb ai/A). Do not apply within 14 days of harvest for hay. Do not apply within 45 days of harvest for grain and straw.

d:Headline should be integrated into an overall disease management strategy that includes proper selection of cultivars with disease tolerance, removal of plant debris in which inoculum overwinters, and plant residue management. Resistance management: do not make more than two applications of Headline/A/year. Determination of treatment threshold: Scout fields weekly from Zadoks' growth stages (GS) 30 through 69 (Feekes' GS 5 through 10.53). For leaf and glume blotch, collect main tillers from 10 plants from 10 randomly selected areas within the field. Examine the appropriate indicator leaf (see Indicator leaves) from each tiller and record the number of indicator leaves with one or more lesions. If 25% of the 100 indicator leaves have one or more lesions, then a fungicide application is indicated. Do not apply to wheat after Zadoks' GS 69 (Feekes' GS 10.53). Do not harvest hay within 14 days of application.

Indicator leaves are: Flag-4 and flag-5 from Zadoks' GS 31-37 (Feekes' GS 6-8)

Flag-3 from Zadok's GS 38-45 (Feekes' GS 8-10)

Flag-2 from Zadoks' GS 46-59 (Feekes' GS 10-10.5)

Do not treat before Zadoks' GS 31 (Feekes' GS 6) first joint (see Figure 1), except in the Tidewater region south of James River. Do not apply more than 4 fl. oz./acre per year or after Zadoks' GS 59 (Feekes' GS 10.50), head emerged, but not flowering. Do not graze or feed livestock treated forage or cut the green crop for hay or silage. After harvest straw may be used for bedding. Follow all label instructions.

Biological Description

Last updated on March 03, 2003.