Socking It to Strawberry Root Rot
By Don Comis
September 24, 2007
Strawberry plants grown in
compost-filled mesh tubes, or socks, had significantly less chance
of getting black root rot, a severe threat to yields, than plants grown
directly in infested soils in an Agricultural Research Service (ARS) study.
No methyl bromide or any other soil fumigant was used in the study, since
they have become too costly for many small growers and nonchemical alternatives
are being sought. The sock plants yielded 16 to 32 times more fruit than those
from the conventional "matted row" or black plastic mulch systems
when grown in infested soil with no soil treatment.
The compost socks lay on top of the infested soil. The disease didnt
migrate into the socks and roots of the strawberry plants during the first
growing season, as it did into the strawberry plant roots growing in infested
soil. Drip irrigation provided water and supplemental nutrients to the plants
in the compost socks.
D. Millner, with the
Sustainable Agricultural Systems Laboratory in Beltsville, Md., conducted
this studythe first of its kind for strawberries.
Small strawberry growers in the northern United States tend to use perennial
matted rows, in which the runners self-root and form living mats. Some
operations that grow strawberries as annual plants use black plastic mulch.
Soil fumigants are used to control root diseases, weeds and nematodes.
In addition to horticultural production, compost socks are often used for
road and stream bank stabilization, flood control, and to hold back silt at
Millner experimented on three farms in central Maryland, each with different
soil types. She rated the root health of the strawberry plants on a scale of 1
to 5, with a rating of 5 meaning the plants were totally free of root rot. All
but one plant grown in the compost socks scored 4 or 5, while those grown in
matted rows or plastic scored from 1 to 3, except for one rating of 4. A study
comparing compost socks with fumigation and crop rotation is being completed.
more about the research in the September 2007 issue of Agricultural
ARS is the U.S. Department of
Agricultures chief scientific research agency.