I was unable to find any information on the Internet regarding a Startaviska lilac. Mealy bugs can look like dabs of cotton, but they do not create a web. Spider mites produce a web, but it does not usually look like cotton. This link includes treatment for each of these problems: http://www.starkbros.com/growing-guide/how-to-grow/garden-plants/lilacs/pest-and-disease-control I don't know which problem you have. Either of these pests could cause crinkled leaves. Leaf damage could have been cause by the hard freeze we experienced in early April. Mealy bugs can be difficult to treat. A lilac is a very hardy shrub. If your plant doesn't have a lot of damage, no treatment may be needed. We could be more helpful if you provided a photo.