If
PesticideData <- read.csv("~/PesticideData.csv")
is not giving you an error, then the data are being read into a data frame named PesticidedData. If that is giving you a error, try writing out the entire path to the file. On my systems that would be either
#Linux system
PesticideData <- read.csv("/home/fjcc/R/PesticideData.csv")
or
#Windows system
PesticideData <- read.csv("c:/users/fjcc/Documents/R/PesticideData.csv")
but you have to know where the file is.