Potato culture is very sensitive to the pathogen attack. Of these, the most frequently reported is Phytophthora infestans. Late blight can cause in favorable years a 40-50% loss of the harvest if the control measures are not applied. In our country, Potato late blight is frequent and dangerous in the area of cultivation, especially in the rainy years, when the production losses can reach 50% or more. The evolution of the attack degree in 2017 is explosive, after 20 days of the first reading. If the first two readings in July show a level below 3%, in the third decay of the month, the average attack exceeded 20%. One of the oldest substances used to control these pathogens is copper. This substance is still valid and still accepted in organic farming. Climatic conditions strongly influence the efficiency of copper fungicides. Also, previous studies claim that there are differences in efficacy between the three chemical formulations of copper. This paper aims to determine the effectiveness of different formulations of this substance. Thus, copper sulfate, copper hydroxide, and copper oxychloride were tested on three varieties of potatoes (red, white, and purple). For control of downy mildew, the most efficient was the oxychloride followed by copper hydroxide. In the variant treated with copper sulfate, the average attack rate exceeded 30%. The highest levels of the attack were recorded in the variants treated with CuSO4 in both the Sante and Red Fantasy varieties. The differences between these two variants and all others are significant. Comparing the varieties is observed that the least attacked by the Phytophthora infestans is the purple variety, the differences between this variety and the others are covered statistically. The most sensitive to the late blight attack was found to be the Sante variety. Of the fungicides tested, the highest efficiency we noted at the copper oxychloride.

potato, Phytophthora infestans, copper, fungicide

biology

Presentation: oral