Watermelon (Syngenta), drying of plants, curling, cracking of fruits - need help

Hi All,

Big issue in Watermelon Farm

Type of seed - Syngenta Sugar Queen
Date of Plantation - 15 March 2015
Problem started since last 2 weeks (20th April)
Temp range - 42 deg C - 46 deg C
Irrigation Type - Drip
Fruit Size - length ranging from 10cm to 30cm (some of them are more than 30 cms), Diameter 5cm to 25cms
Water management: a> Till flowering and small fruit size 1-2 hrs daily
                              b> Since last 5-7 days, gradually increased to 5 hours daily

Problems
1>Plants Getting dried and fruits of those plants getting hard, it is spreading, earlier farm was lush green and now it is getting dried
2>Curling of leaves changing color from dark green to pale yellow and finally dried
3>Fruits are cracking, some fruits are rotting at end.

Please let me know reasons what is going wrong and how to cure this.

Regards,
Krushan

I would suspect either a fungal disease or just the summer heat at work. In spite of irrigation, watermelon leaves crinkle in the sun, so is it just extreme sun?

Pics will help.

Thank you very much.

I am not equipped with camera, I shall arrange and post the photos.