Fungicidas no controle da ''mela'' da batatinha (Solanum tuberosum) causada por Phyophtora infestans (Mont) de Bary

Resumo

The paper describes an experiment in the field that was conducted to determine the effeciency of nine fungicides in the control of "late blight" (Phytophthora infestans ) and ''early blight" (Alternaria solani). The nine fungicides tested were: A)Manzate (Maneb 80%) at 0, 2%, B) Manzate Maneb(80%) 0,15% +Batasan ou Brestan 20% at 0,05%, C) Manzate D (Maneb 78% + Zn** 2%) at 0, 15% + Batasan or Brestan 20% at 0, 15%, D)Maneb 78% + Znt* 2%) at 0,2%, E) Dithane M-45 ( Maneb 78% + Zn** 2%) at 0,2% F) Dithane M 45 ( Maneb 78% + Zn**2%)at 0,15% + Batasan or Brestan 20% at 0,05%,G) Brestan 60% at 0,06%,H ) Sandoz Copper ( Cuprous oxide ) at 0,3% and I) Blue Cuprosan (copper oxicloride) at 0,5%.

The different treatments were sprayed with fungicides 30 days after planting (on May 6 th, 1965) and ther once aweek for 6 weeks. The experiment was also sprayed with a systemic fungicide "Demoton' 21 days after planting and twice more at 3 week intervals. "Late blight" infection occured in all the treatments, however there was no "early blight'  infection.

Alghough Dithane M-45 and Manzate D are the same chemically the former gave better control than the later. Perhaps this is because of the better physical properties of Dithane M-45.

Treatments with Manzate + Batasan, Dithane M-45, and Dithane M-45 + Batasan had significantly higher yeilds and better looking foliage than with the other treatments.