Studies On Biological Characteristics Of Alternaria Radicina And The Field Control Effect To Carrot Black Rot

Carrot black rot caused by the fungal pathogen Alternaria radicina, is a devastating disease. To understand the morphology and biological characteristics of A. radicina, isolates of A. radicina were collected and examined their biological characteristics of A. radicina. The results show that:1. According to the morphology of the colony, the conidiophore and the conidia, the pathogen was identified as A.radicina2. The temperature of spore germination ranged from 24℃ to 32℃. The optimum temperature of spore germination is 28℃. The pH values of spore germination ranged from 4-10.The mycelium of A. radicina grows more quickly on PDA at 28℃.3. The carbon source (glucose, maltose, mannitol, lactic acid, cane sugar, citric acid sodium, soluble starch) can influence the mycelium growth. Growth rate of mycelium of A. radicina were highest in including glucose or sucrose culture medium. Urea, (NH4)2SO4, KNO3, easier, NH4NO3 and Ammonium oxalate can influence the mycelium growth. The mycelium of A. radicina grows more quickly on including Urea culture medium.4. Studies on the field controlling effect of 7 different fungicides to carrot black rot and the yield increasing role were carried out. The results showed that all these different fungicides had certain controlling effects to carrot black rot. The best one among them was 40% chlorothalonil SC with 76.38% of controlling effect. (202.5 mL/666.7m2)...