The picture shows not mealybugs or cottony cushion scale, but soft scale insects:

Order Hemiptera: Suborder Sternorrhycha: Superfamily Coccoidea: Family Coccidae: genus Pulvinaria. Nine species of Pulvinariaare known to occur in India: P. aligarhensis, P. durantae, P. floccifera, P. iceryi, P. indica, P. ixorae, P. obscura, P. polygonataandP. psidii.

Pulvinariais a very large genus of soft scale insects. The species are difficult to identify, and identification requires production of high-quality slide mounts and examination of them at high magnifications using a compound light microscope. The best specimens for identification purposes are the young adult females just before or just as they are beginning to produce the white ovisac. Old females (which have produced large ovisacs) like the ones in your photograph are much more difficult to prepare on slides and identify.

The population is about to explode, as all those white waxy ovisacs are full of eggs. Mineral oil emulsion sprays should kill the hatchlings without seriously affecting the predators and parasitoids in the crop.