common smut of corn

affect africa agricultural agriculture agriculturer agronomy algeria america bacteria blister boil branch burn cancer caused chlorophyll chlorose chlorosis common corn country countryside cuitlacoche curling destruction disease diseased downy etiolation feed field flower fongicide food fungi fungus gall green huitlacoche leaf leaves line maize maydis mediterranean mexico mushroom natural nature necrose pathogen pathogens pattern pesticide phytopathology plant showing smut stem symptom teliospores tissue tumor ustilgo zeae