\docType{data}
\name{Sunflower_Phomopsis}
\alias{Sunflower_Phomopsis}
\title{Phomopsis stem canker observations for Sunflower}
\format{a \code{RangedData} instance, 1 row per observation.}
\source{
  Debaeke, P., & Estragnat, A. (2009). Crop canopy
  indicators for the early prediction of Phomopsis stem
  canker (Diaporthe helianthi) in sunflower. Crop
  Protection, 28(9), 792-801.
  doi:10.1016/j.cropro.2009.04.011
}
\description{
  This dataset contains fraction intercepted
  photosynthetically active radiation (IPAR) and
  corresponding percent of girdling lesions at harvest
  (pclesions) for 43 fields. Phomopsis stem canker is a
  worldwide fungal disease of sunflower, which causes stem
  girdling lesions and a consequent reduction in yield.
  One wants to decide if the number of girdling lesions at
  harvest in the absence of early treatment will exceed 15%
  (Debaeke & Estragnat, 2009). If the answer is yes
  (population X1) then one should treat, if the answer is
  no (population X0) then a treatment is not needed. An
  early indicator of the final number of lesions has been
  proposed, namely fraction intercepted photosynthetically
  active radiation (IPAR) at the early E2 growth stage.
  Larger values of IPAR correspond to greater vegetative
  development , which leads to higher humidity in the
  canopy. This in turn favors disease development. We want
  to quantify the usefulness of early IPAR for determining
  if the number of girdling lesions at harvest in the
  absence of early treatment will exceed 15%. This data
  frame consist of a sample of fields with values for IPAR
  (ipar) and for the percent of girdling lesions at harvest
  (pclesions).
}
\keyword{datasets}

