Study on Nattrassia mangiferae, the Causal Agent of Apricot Tree Decline Disease in the Oases of South Tunisia: Biology and in Vitro Evaluation of Some Fungicides

Nattrassia mangiferae (H. & P. Syd.) B. Sutton & Dyko is a wood fungus causing serious apricot decline in the oases of the South of Tunisia. In the literature there is relatively little information on the biology of N. mangiferae. The objective of this work was to determine the effects of temperature, pH, culture media and some fungicides on the radial growth of N. mangiferae on culture media, and the effect of humidity on conidial germination. N. mangiferae was able to grow on temperatures ranging from 20-40°C with an optimum between 30-35°C. Mycelial growth was best at pH 6. The best medium for mycelial growth was potato dextrose agar (PDA). Maximum conidial germination occurred at relative humidity higher than 90%. The systemic fungicide Benomyl (Benlate) was less effective than the nonsystemic fungicides: Mancozeb (Dithane M45) and Maneb (Manebe 80).