Until now I didn't find any work on insect borer of tree species control, but there is work on maize borer.

https://link.springer.com/article/10.1007/s10658-019-01814-y

Borers can be from coleuptera or from lepedoptera .The endophytic fungus Acremonium lolii Latch can be on borers of coleoptera such as the Argentine stem weevil Listronotus bonariensis (Kuschel) (Curculionidae); in particular,on larval feeding behaviour, growth and survival.

My problem is Coleopteran borer of tree species (Populus deltoides)

Need any work done on coleoptran borer using endophytes fungus?

Amin et al., 2014. The study on the role of entomopathogenic fungal endophytes in controling the cocoa pod borer on cocoa plant

Hello, maybe these articles help you:

The root microbiome: Isolating a functionally relevant guild of fungi from the Populus rhizosphere. https://www.osti.gov/servlets/purl/1327688

Endophytic fungi from the hybrid 'Neva' of Populus deltoides Marsh M Populus nigra L. and their antimicrobial activity. Article Endophytic fungi from the hybrid 'Neva' of Populus deltoides...

Yes, I am working in Agroforestry, many borers are damaging Agroforestry tress..