May 18, 2007

一个简单的代价nefit evaluation can be used to determine the potential profit from applying a fungicide to control wheat diseases. The potential profit will vary with the estimated preventable yield loss from applying the fungicide, yield potential of the crop, wheat price, and the cost of buying and applying the fungicide. The estimated preventable yield loss depends on several factors including favorability of the environment to disease development and susceptibility of the wheat cultivar planted to diseases. Yield potential depends in part on agronomic practices. Selling price can vary from year to year. Fungicide application cost depends on the price of the specific fungicide and can vary from year to year.

The cost benefit formula is:

(PYL x YP x SP)- FAC = PP

where

PYL = Preventable Yield Loss (%)

YP = Yield Potential (bu/ac)

SP = Selling Price ($/bu)

FAC = Fungicide Application Cost ($/ac)

And PP = Potential Profit ($/ac)

Table I如果估计显示了潜在的利润预期preventable yield loss is held constant at 10%, 15%, and 20%; yield potential rises in five bu/ac increments; selling price is held constant at $4/bu; and fungicide application cost is held constant at $20/ac.

Table II如果估计显示了潜在的利润预期preventable yield loss is held constant at 10%, 15%, and 20%; yield potential is held constant at 60 bu/ac, selling price rises in $0.50/bu increments; and fungicide application cost is held constant at $20/bu.

FromTables I and II, it can be seen that the preventable yield loss resulting from applying a fungicide and the selling price of wheat both have a strong influence on the potential profit to expect. The potential profit increases significantly with increasing preventable yield loss and increasing selling price.

Stephen Wegulo
Extension Plant Pathologist, Lincoln

Table I. Potential profit (PP) to expect if estimated preventable yield loss (PYL) is held constant at 10%, 15%, and 20%; yield potential (YP) rises in 5 bu/ac increments; selling price (SP) is held constant at $4/bu; and fungicide application cost (FAC) is held constant at $20/ac.
PYL (%)	YP (bu/a)	SP ($/bu)	FAC ($/a)	PP ($/a)
10	30	4.00	20.00	-8.00
10	35	4.00	20.00	-6.00
10	40	4.00	20.00	-4.00
10	45	4.00	20.00	-2.00
10	50	4.00	20.00	0
10	55	4.00	20.00	2.00
10	60	4.00	20.00	4.00
10	65	4.00	20.00	6.00
10	70	4.00	20.00	8.00
10	75	4.00	20.00	10.00
10	80	4.00	20.00	12.00
10	85	4.00	20.00	14.00
10	90	4.00	20.00	16.00
10	95	4.00	20.00	18.00
10	100	4.00	20.00	20.00
10	105	4.00	20.00	22.00
15	30	4.00	20.00	-2.00
15	35	4.00	20.00	1.00
15	40	4.00	20.00	4.00
15	45	4.00	20.00	7.00
15	50	4.00	20.00	10.00
15	55	4.00	20.00	13.00
15	60	4.00	20.00	16.00
15	65	4.00	20.00	19.00
15	70	4.00	20.00	22.00
15	75	4.00	20.00	25.00
15	80	4.00	20.00	28.00
15	85	4.00	20.00	31.00
15	90	4.00	20.00	34.00
15	95	4.00	20.00	37.00
15	100	4.00	20.00	40.00
15	105	4.00	20.00	43.00
20	30	4.00	20.00	4.00
20	35	4.00	20.00	8.00
20	40	4.00	20.00	12.00
20	45	4.00	20.00	16.00
20	50	4.00	20.00	20.00
20	55	4.00	20.00	24.00
20	60	4.00	20.00	28.00
20	65	4.00	20.00	32.00
20	70	4.00	20.00	36.00
20	75	4.00	20.00	40.00
20	80	4.00	20.00	44.00
20	85	4.00	20.00	48.00
20	90	4.00	20.00	52.00
20	95	4.00	20.00	56.00
20	100	4.00	20.00	60.00
20	105	4.00	20.00	64.00

Table II. Potential profit (PP) to expect if estimated preventable yield loss (PYL) is held constant at 10%, 15%, and 20%; yield potential (YP) is held constant at 60 bu/ac; selling price (SP) rises in $0.50/bu increments; and fungicide application cost (FAC) is held constant at $20/ac.
PYL (%)	YP (bu/a)	SP ($/bu)	FAC ($/a)	PP ($/a)
10	60	3.00	20.00	-2.00
10	60	3.50	20.00	1.00
10	60	4.00	20.00	4.00
10	60	4.50	20.00	7.00
10	60	5.00	20.00	10.00
10	60	5.50	20.00	13.00
10	60	6.00	20.00	16.00
15	60	3.00	20.00	7.00
15	60	3.50	20.00	11.50
15	60	4.00	20.00	16.00
15	60	4.50	20.00	20.50
15	60	5.00	20.00	25.00
15	60	5.50	20.00	29.50
15	60	6.00	20.00	34.00
20	60	3.00	20.00	16.00
20	60	3.50	20.00	22.00
20	60	4.00	20.00	28.00
20	60	4.50	20.00	34.00
20	60	5.00	20.00	40.00
20	60	5.50	20.00	46.00
20	60	6.00	20.00	52.00