41 



chlortetracycline hydrochloride (Sigma Chemical Co., St. Louis, MO 

 63178) per liter of medium was used to monitor the antagonist popula- 

 tions. Soil dilutions in water of 1:25, 1:100, and 1:1000 (wtivol) 

 were employed and plates were stored at 25 C and 2000 lux of 12 hr of 

 fluorescent light per day for ? days before examination for fungal 

 colonies. 



A standard hygro thermograph was used to monitor the high and low 

 temperatures during the growing season. 



The effect of the treatments on yield and disease incidence were 

 determined. Yield data were obtained by harvesting all of the fruit 

 that were past the mature green stage of ripeness each week for 4 con- 

 secutive weeks. Fruit weight and number were recorded for each plot. 

 Disease incidence, as determined by the presence of lesions on the crown 

 and lower stems of the plant, was determined at the last harvest date. 

 Sections of the stems at the edges of the lesions were plated on 

 Komada's (l6) medium to confirm the presence of the pathogen. 



A randomized, complete-block design with eight treatments repli- 

 cated five times was used. There were 20 plants in each plot. The 

 entire experiment was repeated in the field two times at 2 wk intervals. 



Results 

 The incidence of Fusarium crown rot of tomato was affected signifi- 

 cantly (P = 0.05) by the initial inoculum density of F. oxysporum f . sp. 

 radicis-lycopersici , the antagonist amendment, and the time of planting 

 (Table 5 ) • The increase in disease observed during the later planting 

 time as compared to earlier planting times was associated with cooler 

 prevailing temperatures. The mean low temperature during the first and 



