dolabriform A botanical term, pick-shaped and attached toward the middle, or at some point along the length rather than at an end.

dollar spot on lawns A fungus (Sclerotinia homeocarpa) encouraged by spring's warm, wet, weather and fall's wet weather with cool nights. Lawns low on fertilizer (esp. nitrogen), or poorly drained areas are most susceptible. This disease is recognized by small, round, brown spots later becoming straw colored. A white cobwebby fungus growth seen most easily in early morning before the dew dries; may cover dying leaf blades. The best options for preventing this fungus is to plant resistant varieties of grasses and to water deeply, infrequently, and in the morning.

dolomite or dolomitic limestone A mineral of calcium magnesium carbonate usually from compacted limestone beds. It is sometimes applied to growth mediums to supply both calcium and magnesium carbonates while raising the soil pH.

domestic well A water supply from a well for household use.

dominant With regard to plant materials, a species that is most characteristic of a habitat, or that tends to crowd out other plant species.

donor site See transfer of development rights and sending site.

door head 1. In framing, the upper horizontal member of the frame for a door. 2. In finish design, any projection immediately above a door that gives emphasis to the top of the door.

dormancy 1. Plants or seeds that are alive, but not growing. 2. A regularly occurring period when plant growth processes greatly slow down or growing ceases. This occurs in many species in the temperate region beginning in winter as cold days grow shorter and temperatures begin to lower; this ends in spring when plants are exposed to higher temperatures and longer days. Dormancy protects plants against extremes of temperature. It is usually best not to fertilize during dormancy.

dormant oil A highly refined oil used for spraying on deciduous shrubs and trees while dormant (preferably shortly before bud break) that kills eggs and or insects, usually by smothering. It can kill tender herbaceous understory plants, so it is best to cover them before spraying.

dormant spray A sprayed application of fungicide, oil, or insecticide during a plant's dormancy. This is a very effective way to assist in controlling disease. See also dormant oil.

dorsal In botanical terms, the back or outer surface of an organ.

dorsifixed A botanical term used in plant identification, attached on the back. (Compare with basifixed.)

dote or doat or doze A dull appearance in wood indicating decay has caused it to become weak.

double-acting pump A pump in which the up and down motion of a piston moves water as it moves in each direction.

double axe An axe having a blade on both sides of its head.

double check assembly A backflow device with two internally loaded, independently operating check valves together with tightly closing, resilient-seated shutoff valves upstream and downstream of the check valves with resilient-seated test cocks for testing of the assembly. It may be used to protect against a pollutant only.

double corner block or pier block or pilaster block A concrete masonry unit having rectangular end faces and rectangular side

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