Q.staghorn fern dying
The staghorn fern looks dead with no growth on the too 1/2 of the hanging basket. we thought it might have aphids so a week ago we sprayed it with malathian. Please help. It used to be so plentiful but now half dead.

What made you think you had aphids? Did you see a black sticky substance? Interestingly enough, staghorn ferns are prone to black spot, which is a fungal disease and is characterized by black spots on leaves which kinda looks similar to the black sooty mold caused by aphids. I have included a link to an article about black spot below so you can take a look and see what you think and take measures, if necessary. Barring that, I would review an article on our website on staghorn ferns (link below) and make sure you giving it the water, lighting and fertilizer that it requires.
Black spot information:
https://www.gardeningknowhow.com/plant-problems/disease/black-spot-fungus.htm
Aphid information - includes natural control methods:
https://www.gardeningknowhow.com/plant-problems/pests/insects/homemade-aphid-control.htm
For more information on the care of staghorn ferns, please visit the following link:
https://www.gardeningknowhow.com/ornamental/foliage/staghorn-fern/staghorn-fern-information.htm