Arthashastra
क्षीण कृण काष्ठ उदकम् असंस्कृत दुर्गम मित्रं वासन्तिकं च अस्य सस्यं वार्षिकीं च मुष्टिम् उपहन्तुं ज्येष्ठामूलीयां यात्रां यायात् ॥
He should march during the month of Jyestha (May-June) against one whose storage of fodder, firewood and water has diminished and who has not repaired his fortifications, if he means to destroy the enemy's vernal crops and handfuls of the rainy season.
english translation
kSINa kRNa kASTha udakam asaMskRta durgama mitraM vAsantikaM ca asya sasyaM vArSikIM ca muSTim upahantuM jyeSThAmUlIyAM yAtrAM yAyAt ॥
hk transliteration by Sanscript