black knot


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black knot

[¦blak ‚nät]
(plant pathology)
A fungus disease of certain fruit and nut trees that is characterized by black excrescences on the branches; destructive to plum, cherry, gooseberry, filbert, and hazel.
References in periodicals archive ?
The ATB Blank-Spectra system, being the most budget-minded, is capable of reliably detecting sound knots, black knots, and bark pockets.
Both systems were able to partially or correctly detect mineral streak, discoloration, sound knots, black knots, burl pocket, decay, blue stain, wane, split ([greater than or equal to] 0.
Small black knots that are tight and not over 1/2" (12.
diameter (this type of knot is desirable and as many as possible should be included on the good side); splits within the knots are acceptable unless they seriously weaken the part and cannot be filled; occasional small black knots if they are tight and not over 1/4 in.
This grade will not permit black knots larger than 1/4 in.
of knots 0 Sound knots Not allowed Black knots Not allowed Rotten knots Not allowed Cracks Not allowed Discoloration Max 33% of top diameter over bark Grade Property 2 Allowed lengths (m) 3.
This grade will permit any size or number of round red knots (splits within the knot are acceptable and splits around the knot are acceptable up to 2/3 of the circumference of the knot); small black knots which are tight and not over 1/32 in.