Holly leaves turning Brown


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Old 04-28-00, 06:44 PM
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I have a large holly tree, about 18ft. talll. About a month ago I noticed the leaves getting spots of brown then become dry and the dryness spreads throughout the leaves. It is getting out of control now. Suggestions? Spraying?
Calford
 
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Old 04-29-00, 08:43 PM
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Hollies are generally pest/disease free unless they are under stress from overwatering, soil compaction or not enough sunlight. Blackening of foliage is generally not an insect problem. Leaf minors that tunnel through holly foliage leave light green to yellow tunnels in the foliage but do cause the foliage to dry out. Spider mites can also cause yellowing of the leaves and drying out, but not usually blackening of the foliage. Scale insects are usually indicated by a scaley or stippled looking stems and leaves. Blackening of the foliage is usaully disease based and can be leaf spot or holly decline. Leaf spot is a fungal disease that is generally caused by stress on the plant for one or more of the reasons listed above. You can cure leaf spot by spraying the tree with lime-sulfur spray but unless the underlying cause is determined, the problem will re-occur. Decline can only be cured by correcting the stress on the plant. Examine carefully the tree both in the damaged sections and in the sections on the edges of the tree for any insect activity. To check for spider mites, take a white piece of paper, hold it under the edge of a damaged section such that the paper is 1/2 under healthy and 1/2 under damaged and shake the branch vigorously. Spider mites are so small as to be almost invisible to the naked eye and will appear only as small specks on the paper. If the specks on the paper are moving and leave a brown smear across the paper when you brush your hand across the paper, then you have spider mites. Control is usually effected by spraying the plant with a garden hose on full force or by spraying dormant oil in temperatures below 80 degrees farenheight or by using insecticidal soap, superior or panific oil. Dormant oil or panific oil will control scale insects. In severe cases a systemic insecticide may be considered for insect infestations. Leaf miner controls are usually only partially effective at best as the insects are actually inside the foliage and protected from most sprays. Pruning out severely infested areas of the plant are usually the best control.
 
 

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