Chemical spraying in St. Croix resulting in dying birds.

I am doing research on the effects of Chemical spraying on wildlife (ex. birds,plants, and butterflies mostly). I am finding great information, however, I came across a small amount of information linking St. Croix with Chemical spraying. It said this happened in the 1970's or 1980's and it killed off most of the birds and butterflies there in St. Croix. The information said the animals and insects are just now finally beginning to recover from this chemical spraying. I would like to put this information in my report, however, I am finding it extremely difficult to find out any information. Does anyone know anything about this? Did this actually take place and if so, do you know when? How bad was it there? Any information at all would be extremely helpful. Thank you so much for any insight you can give me on this information.