The bagworm caterpillar lives its entire life inside a tough protective case made of silk and camouflaging bits of foliage. Each caterpillar makes its own bag that it carries around as it feeds with the head and legs sticking out the open, top end of the bag.  As the caterpillar eats and grows the bag is enlarged until by the end of the summer, what started as tiny pods only one-quarter inch long will have grown to almost 2 inches in length.

Acorn and Nut Weevils

The adult acorn weevil is a brown beetle about 3/8 inches in length, and has a very long, thin snout.  The larvae are legless grubs which are curved and fat in the middle, tapering toward both ends.  The larva is creamy white colored with a brown head, and can grow to be 1/4 to 3/8 inches long.

Pine Wilt

Image of pine wilt on a Scotch Pine
Pine wilt on a Scotch Pine

Overview of pine wilt 

Pine wilt causes rapid wilting and dying of pine trees, particularly Scots (Scotch) pines. Pine wilt is particularly common in scotch pines but is capable of infecting other non-native pines as well.

Rhizosphaera Needle Cast

Rhizosphaera needle cast is the most common disease on spruce trees that is received in the Plant and Insect Diagnostic Clinic. Rhizosphaera needle cast is caused by fungal pathogens within the genus Rhizosphaera. This genus also infects several conifer species including; fir, cedar, spruce, and pine

Oak Wilt

Oak wilt is a serious disease that can infect many oak species. It is caused by the fungus, Ceratocystis fagacearum. Red oaks are very susceptible to the oak wilt fungus and can die within 4-6 weeks.  White and bur oaks are susceptible, but the symptoms develop slowly. Trees can be infected by the fungus through root grafts or by beetle vectors that carry spores to newly wounded trees. When a tree is infected it tree tries to protect itself by producing gummy material called tyloses which can clog the water conducting vessels. Water is prevented from moving to the canopy and leaves begin to wilt. Leaves of infected oaks can wilt, turn brown at the edges, and fall off. The outermost ring of sapwood sometimes turns brown and appears as streaks when the bark is peeled; or as a ring when the branch is cut in cross-section. Because oak wilt is often confused with other disorders, positive identification requires recovery of the causal fungus from the tree.

Dothistroma Needle Blight

Dothistroma needle blight is especially common on Austrian pines.

Diplodia Tip Blight and Canker

Diplodia tip blight is caused by the fungus Sphaeropsis sapinea.

Corn Smut

Need to know:

  • Smut galls are lumpy and mushroom-like with an off-white to grew color.
  • The galls enlarge, filling with fine black spores.
  • The spores can spread easily by wind and water.
  • Prevent this problem by selecting corn hybrids.
  • If older varieties are desired, the gardener should scout early and often, remove galls before they set spore, and avoid overhead irrigation.


Black Knot

This disease is caused by the fungus Apiosporina morbosa and typically affects both wild and cultivated cherry, chokecherry, and plum species. Black cherry and pin cherry are not susceptible to black knot.