Influence of Fungicides on Wheat Disease Incidence and Yield, 1996.

Quadris is an experimental fungicide and was applied at two wheat growth stages. Although there was excessive rainfall and high humidity in May, disease incidence was very low. Therefore, Quadris was not beneficial for preventing or reducing disease infection. Yield ranged from 68 bu/A in the nontreated to 72 bu/A in the treated. There was no difference in yield or test weight.

I. INTRODUCTION:

Foliar diseases can decrease wheat test weight and yield if infection is severe. Fungicides may reduce the incidence of infection when environmental conditions are favorable for disease development. This study was designed to evaluate the fungicide, Quadris, applied at two wheat growth stages.

II. FUNGICIDES EVALUATED:

      Quadris 80 WP
      Tilt 2 EC

III. ABBREVIATIONS USED:

      F9: Feekes 9
      F10: Feekes 10
      TRZAW: wheat

IV. RESULTS AND DISCUSSION:

An extended period of rainfall occurred in which 11 inches of rainfall was received in April yet disease incidence was very low.

Percent Flag Leaf and Head Infection:

There was no incidence of disease even in the nontreated plots despite an extended period of rainfall in April and early May. Therefore, percent flag leaf and head infection was rated 0 for all plots. Head scab incidence also was low in the study area. The study area is slightly sloped. Therefore, the lack of disease incidence may be attributed to the drainage of the study area.

Test Weight and Yield:

Test weight ranged from 57 to 58 lb/bu. Yield ranged from 68 to 72 bu/A. There was no difference in test weight or yield. This is a reflection of no disease pressure. Therefore, the application of a fungicide was not beneficial despite the excessive rain.

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