Helminthosporium leaf blight of forage sorghums in Southern California
HELMINTHOSPORIUM LEAF BLIGHT, caused by the fungus Helminthosporium turcicum, was first noted on sudan leaves in San Bernardino and San Diego counties in 1956. Tests conducted in San Bernardino County in 1954 showed Sudan 23 and Piper to be the highest yielding varieties. At that time, they were outyielding Tift by about 20%. Consequently, most sudan acreage during this period was planted to the susceptible variety, Sudan 23. Characteristic symptoms of the Helminthosporium disease on sudangrass are elongated, linear lesions. The lesions are water soaked at first, and then turn brown to straw color. Under conditions favorable to the disease in San Bernardino and San Diego counties, entire leaf blades are killed.