Effects of environmental factors on conidial germination and infection of Pestalotiopsis spp. causing twig blight disease of bayberry(Myrica rubra)in China

【Objective】The twig blight disease is one of the main diseases of Myrica rubra. To develop ef-fective technologies of prediction and prevention.【Methods】Germination of conidia of two Pestalotiopsis fungi infecting bayberry was evaluated after 2,4,6,12,and 24 h incubation under different tempera-tures,relative humidities and nutrition solutions. Infection of the above conidia on bayberry was also eval-uated after 5,7,9,11,13,and 15 d incubation under different temperature and relative humidity.【Re-sults】Conidial germination and infection of Pestalotiopsis species were significantly affected by tempera-ture and relative humidity. The temperature of 20 to 30 ℃ and 25 to 35 ℃ were the most suitable for theconidial germination and infection respectively. The conidial germination rate was near or more than 50%incubated for 48 h under the relative humidity of 60% or higher. The optimum relative humidity for infec-tion was 60% to 80%. The conidia germinated in water with low rates,and well germinated in the 0.1%solutions of glucose,potato fried juice,sucrose,potassium nitrate and potassium dihydrogen phosphaterespectively.【Conclusion】The results of this study indicated the conidia of Pestalotiopsis fungi infectingbayberry could germinate and infect in a large range of temperature and relative humidity,and use a vari-ety of nutrition.