Sugarbush Diseases and Insects
The following information has been taken from: Sugarbush Management: A Guide to Maintaining Tree Health
Major Early-Season Defloliators
Major Late-Season Defoliators
Conspicuous Insects of Little Consequence
Some insects and mites alter plant growth when they stimulate the host to produce strange-looking growths called galls. These tumor-like abnormalities are derived from cells that grow excessively large or numerous. This unusual development is triggered by growth stimulants introduced into the plant in the saliva of insects and mites. The location, shape, and color of a gall, which provides a source of nutritious and readily available food and shelter for the pest, usually is distinctive enough to identify the gall maker.
A tree disease can be caused by abiotic factors such as air pollution, mineral imbalances, and climatic extremes; by biotic agents such as tiny viruses, bacteria, mycoplasma-like organisms, and fungi; by nematodes; or by larger parasitic plants such as mistletoe and broomrape. Nearly all diseases of sugar maple incited by biotic agents are caused by fungi. Like insects, fungi can be classed as primary (able to successfully infect and invade healthy vigorous trees altered by stress). Collectively, diseases probably cause more losses to sugar maple than all other destructive agents.
Diseases of sugar maple range from conspicuous, but rarely significant, leaf diseases to inconspicuous, but often lethal, diseases of internal stem wood and roots. The presence of many diseases often goes unnoticed until the damage is significant. And since little can be done to halt their progress, it is important to prevent or reduce the conditions that lead to tree diseases. Nearly all biotically incited diseases of major consequence other than dieback/declines are facilitated by wounds. Wound prevention, especially to roots and lower stems, must be central to an IPM program for sugarbushes.
Dieback/decline diseases epitomize the complex nature of tree diseases for they reflect the interactions of fungal pathogens and various stresses, including defoliating insects, as well as adverse abiotic factors. Their complex etiology also serves to emphasize the need for a holistic approach to managing the sugarbush.
Cankers and Canker Rots
Stem cankers are conspicuous tree diseases in that they generally deform the lower tree bole and often render it unsuitable for tapping. Cankers themselves often are points of entry for decay fungi, and create weak points where trees often break. Affected trees should be removed so long as doing so would not create a large opening in the canopy that, as mentioned earlier, would encourage unwanted vegetation or promote excessive soil drying.
Decays of Stems and Roots
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