OTHER CAUSES OF PLANT PROBLEMS - CROWN/FOLIAGE

A variety of environmental and mechanical factors can cause plant problems. These factors may be the primary cause of the problem, or they may be secondary, placing additional stress on the plant. This weakens the plant's defense system and resistance to plant disease.

Abiotic (non-infectious) factors are usually caused by adverse environmental conditions. Abiotic causes of plant problems may include:

	FALL NEEDLE DROP The oldest needles (innermost needles) on conifers turn yellow to brown and drop from the tree in the fall. Photo by Chad Behrendt
	WINTER INJURY Browning and desiccation of needles near the tree top which are not protected by the snow cover. Photo by Department of Plant Pathology
	UNUSUAL NEEDLE BROWNING (DELAYED DORMANCY) Rapid browning and death of needles on the top or side of the tree. This problem appeared in the spring of 1999 affecting only spruce. The theory is that trees did not go dormant until mid-December due to warm temperatures. Photo by Chad Behrendt
	NUTRIENT DEFICIENCY Trees planted on alkaline soils may become chlorotic (develop yellow-green needles) due to an iron deficiency. Photo by Chad Behrendt
	SALT DAMAGE Pine trees planted near road sides can develop red-brown needles as a result of deicing salts used during the winter. Photo by Plant Disease Clinic
	HAIL DAMAGE Hail injury can cause brown needles, wounds on the branches or trunk, and branch dieback. Photo by Chad Behrendt
	FLOODING Prolonged periods of standing water may kill roots, causing decline, dieback, or death of the tree. Photo by Dave McDonald
	ROOT DAMAGE Root damage may cause wilting, dieback, or death of trees. Photo by Department of Plant Pathology

Animals may cause browning of needles, due to girdling of the branches or trunk.

SAPSUCKER DAMAGE Multiple rows of holes caused by sapsucker feeding will girdle the tree. This causes drought-like symptoms to develop on the needles (browning of the needles). Photo by MN Extension Service

Insects can cause symptoms similar to plant disease.

SPRUCE GALL Insect galls (Cooley spruce gall) can cause distortion of branch tips and dieback. Photo by Chad Behrendt

Refer to the following web pages for more information on insects.

University of MN, Department of EntomologyUniversity of MN, Integrated Pest Management


Abiotic causes of plant problems may also include improper cultural practices. Refer to the following web page for information on proper tree care.

Planting & Care


For more information on how to identify and control noninfectious diseases

Plant Disease Diagnostics
University of Minnesota, Yard and Garden Clinic
Developed (1999) and maintained by
Chad J. Behrendt, Ph.D. and Crystal M. Floyd

For plant disease questions contact the Yard and Garden Line Content Last Updated 09/07/00 View University of Minnesota Disclaimer