Can kasha be special summoned from the deck to field using pyramid turtle ability as long two other zombies are on field?

Yes, Kasha can be Special Summoned from the Deck to the field by the effect of Pyramid Turtle as long as there are two other Zombie monsters on the field. Pyramid Turtle's effect states that you can Special Summon 1 Zombie monster from your hand or Deck, by sending 1 Level 4 or lower Zombie monster you control to the Graveyard. Kasha is a Level 2 Zombie monster, so it can be Special Summoned by Pyramid Turtle's effect by sending a Level 4 or lower Zombie monster to the Graveyard.