Arthashastra
हैमानं च अस्य सस्यं वासन्तिकं च मुष्टिम् उपहन्तुं चैत्रीं यात्रां यायात् ॥
He should march during the month of Chaitra (March), if he means to destroy the enemy's autumnal crops and vernal handfuls.
english translation
haimAnaM ca asya sasyaM vAsantikaM ca muSTim upahantuM caitrIM yAtrAM yAyAt ॥
hk transliteration by Sanscript