Author : Tangonan, Naomi G.

Summary : Two sorghum croppings, a main crop and a ratoon, were conducted to determine the pathogens causing the stalk rot complex in Mindanao and to determine the effects of various cultural management practices and prevailing weather conditions on its occurrence and development. Results show that three fungal pathogens were consistently associated with each other and with the stalk rot complex. These were Colletotrichum graminicola (Cesati) Wilson, commonly causing a "red rot" symptom in sorghum stalks, Fusarium moniliforme Sheldon and MAcrophomina phaseolina (Tassi) Goid. (Rhizoctonia bataticola (Taub.) Butler) better known as responsible for causing "charcoal rot" of sorghum. Because of their synergistic relationship to one another, their combined effect resulted to an etiological phenomenon - the sorghum stalk rot complex. Larger lesions were developed when two or three were associated together. Pathogenicity tests conducted both in the field and greenhouse revealed that significantly bigger lesions developed when the plants were inoculated in the field.