Published online by Cambridge University Press: 31 May 2012
A population index for the estimation of the neosistens stage of pine leaf chermid on white pine is described. This is based on the observation that increasing numbers of the chermid produce increased stunting of length of pine needles. A regression relating chermid population density to needle length produced a correlation coefficient of −0.88, suggesting that measurements of needle length alone adequately estimate chermid populations under most conditions. The numbers and distribution of needles that must be measured to estimate length with reasonable precision are calculated. The total sampling plan for the four cyclic generations of the chermid is reviewed.