Foliage

• The Japanese beetle, green June beetle, European red mite, stink bug, and plum cuculio plant bug may damage the tree's foliage. The caterpillars of the gypsy moth can defoliate an entire tree if control is not promptly gained, according to NC Cooperative Extension. The European red mite attacks the new growth and sucks the tree's nutrients, leaving the leaves deformed.
  
  

Trunk and Limbs

• The peach tree borer feeds on the soft inner bark of the nectarine tree and other stone fruit tree varieties. It can cause widespread damage by girdling young trees. If not promptly treated, the insect can cause the death of the tree.
  
  

Fungus

• The fungus brown rot (Monilinia fructicola) occurs during the spring months and can destroy an entire fruit crop.
  
  

Prevention/Solution

• Utilizing a regular insecticidal spray program on nectarine trees can help prevent most insect pests. Prompt treatment with insecticides of gypsy moth and peach tree borer infestations can help save a nectarine tree's life. Applications of fungicides help control brown rot. Promptly removing fallen fruit and leaves will also help prevent fungal diseases from occurring.