how to hatch a cell in table

Question

\documentclass[a4paper,12pt, twoside]{article}
\usepackage{enumerate}
\renewcommand{\baselinestretch}{1.5}
\usepackage{amsmath,  amsthm,  amsfonts, mathrsfs, latexsym, amssymb,
pstricks,graphicx,setspace,textcomp}
\usepackage{pdfpages,caption}
\usepackage[round]{natbib} 
\bibliographystyle{apa}
\usepackage{cite}
\usepackage{nomencl}
\usepackage{graphicx}
\usepackage{float}
\usepackage{underlin}
\usepackage{url}
\usepackage{longtable}
\usepackage{titletoc}
\usepackage{titlesec}
\usepackage[normalem]{ulem}
\usepackage{hyperref}
\usepackage{caption}
\usepackage{parskip}
\setlength{\parindent}{20pt}
\usepackage{setspace}
 \usepackage{lipsum}
 \usepackage{pdflscape}
 \usepackage{multirow}
\usepackage[utf8x]{inputenc}
\begin document
\begin{landscape}
\chapter*{Plan of work}
\begin{tabular}{|c|*7{p{32mm}|}}
\hline
\multirow{2}{*}{Task}  &  \multicolumn{6}{c|}{Duration}\\
\cline{2-7}
 & Jan-15 to May-15 & June-15 to Dec-15 & Jan-16 to May-16 & June-16 to Dec-16 & Jan-17 to May-17 & June-17 to Dec-17\\
\hline
\multirow{2}{*}{Course Work} &   &  &&&&\\
\cline{2-7}
&  &  &&&&\\
\hline
\multirow{2}{*}{Literature Survey} &&&&&&\\
\cline{2-7}
&&&&&&\\
\hline
\multirow{2}{*}{Develop CZM }   &&&&&&\\
\cline{2-7}
&&&&&&\\
\hline
\multirow{2}{*}{Fracture Toughness}  &&&&&&\\ 
\cline{2-7}
 for pure modes &&&&&&\\
\hline
\multirow{2}{*}{Applying to mixed }  &&&&&&\\
\cline{2-7}
  mode cases &&&&&&\\
\hline
\multirow{2}{*}{Publications and }  &&&&&&\\
\cline{2-7}
 Thesis Preparation &&&&&&\\
\hline
\end{tabular}
\newpage
\end{landscape}
\end document