Symptoms in the image is the downy mildew infection caused by parasitic fungi.
Following sprays may be administered for the management of Downy mildew disease on cucumber crop
1. Kavach 2 gm/L + Ampoxcillin 1 gm/L
https://www.bighaat.com/products/kavach-fungicide + https://www.bighaat.com/products/ampoxcilin-chelated-multi-micro-nutrient-fertilizer
and after a week
2. Ridomil gold 2 gm/L + Kitoguard 2 mL/L
https://www.bighaat.com/products/ridomill-gold-fungicide + https://www.bighaat.com/products/kitoguard-fungicide
K SANJEEVA REDDY
Senio Agronomist, Bighaat India
Disclaimer: The performance of the product(s) is subject to usage as per manufacturer guidelines. Read enclosed leaflet of the product(s) carefully before use. The use of this product(s) /information is at the discretion of user.