• Black hills spruce, a variety of white spruce, occurs naturally in the wild and is native to South Dakota. The spruce tree can grow 30 to 60 feet tall and 15 to 25 feet wide at the top, or crown, of the tree. Vigilance and proper care of black hills spruce can help reduce the chances of infection by spruce tree diseases. Knowing the signs of diseases affecting black hills spruce will help you to take appropriate action and measures to keep the spruce diseases from spreading to the rest of the tree or surrounding spruce trees.
  
  

Spruce Needle Rust

• Spruce needle rust disease isn't caused by one specific fungi. Infection from one of the several species of fungi from the genus Chrysomyxa may infect a black hills spruce. The fungus live on plants from the Ericaceae plant family, which includes azaleas, huckleberries, blueberries and rhododendrons. Cool, wet weather in the spring causes the spores leave the host plant and infect young spruce needles. Infected spruce needles turn yellow and fall off in September at the end of the needles' growing season. In the summer, white or pale orange structures shaped like a tube grow on the spruce needles. These tube-like structures release the orange powdery fungal spores inside. The fungal spores attach to a host plant nearby waiting to start their life cycle all over again. The fungus only affects the color of the needles, but won't kill the tree.
  
  

Lirula Needle Blight

• A fungus called Lirula macrospora causes lirula needle blight disease on spruce trees. Black hills spruce is the most susceptible species to this needle blight. In late May, fungal spores begin to form and continue into August. From early June through mid-July, infected needles release spores when it rains. Infected needles develop yellow bands that turn to a purplish-brown color over the next a year and a half. Between 23 and 25 months later, the needles turn reddish-brown and fruiting bodies, called hysterothecia, appear on the spruce needles as a black, smooth line down the middle. Needles eventually become tan or pale colored. The fruiting bodies mature releasing the fungal spores next year in the spring and summer. Old, infected needles may fall off or stay attached to the spruce branches for several years after infection.
  
  

Cytospora Canker

• Cytospora canker is the most common spruce tree disease found on older, larger spruce trees, according to the North Dakota University Extension. The fungus infects trees through wounds found on the lower branches of the black hills spruce and spreads upward to other branches of the tree. Branches infected with the canker eventually die. The disease spreads by small animals coming into contact with infected branches, rain dripping off of infected needles or pruning tools that have come into contact with infected spruce trees. The needles on the infected branches turn brown and the branches can have white or blue-gray colored patches of dried sap on some or all of the branches. Removing the bark from an area with dried sap on it is the only way to make an accurate identification of the canker. The inner bark will look brown and contain pinhead-sized spores.