How do I control fruit fly and powdery mildew in ash gourd (petha)?

Maggots in young fruit are from fruit fly, managed across all gourds with cucurbit pheromone traps, prompt removal and destruction of infested and fallen fruit, and bagging young fruits on small plots. White powdery patches on leaves and stems are powdery mildew, common in dry warm weather with humid nights and worse in dense vines, so give wide spacing and air flow, avoid excess nitrogen, and apply a recommended fungicide following the label at first sign if pressure is high. Keep the field clean of old crop debris. Since fruit grown for storage is on the vine for a while, watch the pre harvest interval. Confirm the diagnosis and current recommendations with your KVK.