intern_herbicide {PROSPER}

Surviving the Herbicide

Description

Utility function internally used. It's used only by sel_herb, and usually there is no reason to change it. Calculates the surviving number of weeds according to the specific genotype.

Usage

intern_herbicide(resist, n_samples, put, rate, sdrate, thresh)

Arguments

resist

numeric, value of resistance for the genotype (defined by Renton et al. 2011). Shall be \le 1.

n_samples

integer, the number of weeds with one specific genotype.

put

probability of a weed to be untouched by the herbicide. numeric, 0 \le \code{put} \le 1.

rate

percentage (%) of the registered herbicide dose. positive numeric, can exceed 100 %.

sdrate

variance of the herbicide rate reaching the weed. positive numeric, 1 = 1 unit standard deviation.

thresh

threshold herbicide rate to kill weeds without resistance. numeric, 0 \le \code{thresh} \le 1.

Details

intern_herbicide is used in sel_herb. Firstly, it calculates the number of weeds that are untouched by the herbicide by chance (probability=put). In the second step, the herbicide rate that reached an individual is compared with the resistance value (calculated after Renton et al. 2011, sel_resist). If the resistance value is lower than the dose, the weed dies. All surviving weeds are summed up.

Value

The number of weeds surviving the herbicide.

References

Renton, M.; Diggle, A.; Manalil, S. & Powles, S. (2011): Does cutting herbicide rates threaten the sustainability of weed management in cropping systems? Journal of Theoretical Biology, 283, 14-27.

See Also

sel_herb sel_resist

Examples

#How many of 1000 weeds of a genotype with resistance value 5.5 survive a herbicide application 
#with full dose? 'It is assumed that weeds reseaving less than 20 \% of the full dose survive
#independently of their resistant value.
intern_herbicide(resist=5.5, n_samples=1000, put=0.04, rate=100, sdrate=0.4, thresh=20)