Development of a fungicide-based management strategy of inflorescence rot disease caused by Mauginiella scaettae Cavar on date palm (Phoenix dactylifera L.) in Morocco

Abstract

Inflorescence rot is a serious constraint to date palm cultivation in Morocco. However, studies on the management of this fungal disease are limited. We compared seven fungicides (Thiram, Thiophanate-methyl, Copper oxychloride, Mancozeb, Fosetyl-aluminum, Chlorothalonil and Maneb) based on their antifungal activity against the causal agent, M. scaettae, in vitro . Data on the effects of these fungicides on the pathogen mycelial growth, spore germination and sporulation indicate that Thiram, Thiophanate-methyl, and Copper oxychloride had significantly the strongest inhibitory activities. The three fungicide were then tested in an experiment for their abilities to control inflorescence rot on date palm cultivar “Majhoul” under field conditions. The study was conducted following a factorial design with 3 factors; the factor “fungicide” with 3 levels (3 fungicides), the factor “fungicide concentration” having 2 levels (60%, 0.6X and 80%, 0.8X, of the concentration recommended by the manufacturer against other fungal pathogens), and the factor “frequency of sprays” including 3 levels (1, 2, or 3 pulverizations). Results showed that the three fungicides varied significantly in controlling the disease in a dose- and frequency of treatment-dependent manner. When applied three times at the dose of 0.8X, all fungicides completely eliminate the disease. However, with one or two applications, Copper oxychloride had significantly the greatest percentages of disease control, 69% and 96.8% respectively. Therefore, two application of Copper oxychloride at the dose of 0.8X can be recommended for preventive control against inflorescence rot on date palm.