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7 > Image 7 of Kentucky fruit notes, vol. 4, No. 1, January 1949

Part of Kentucky Agricultural Experiment Station

Y.; Q .; 7 SOME STRAWBERRY DISEASES W. D Armstrong B12.f2~E The red stele root rot disease has long been a serious problem in the strawberry producing sections of Illinois, New jersey, and a number of other states. Kentucky growers have been very fortunate in that losses from this disease have been relatively light, to date. The writer first saw the disease in an Aroma patch near Paducah in the spring of 1939. Another strawberry crop was planted on this sarne field in 1944 and was again virtually ruined by red stele in 1945. It was seen in a few other berry fields in the Paducah section and I at Lexington in 1947 and it is suspected to be spread more generally than is realized. In 1948 additional evidence of the disease causing injury around Louisville and Covington was seen. The disease is caused by a fungus that thrives in poorly drained soils and causes most injury in cool, wet seasons. The disease is often carried to 1 the new field on the roots of the newly set plants and can be spread by surface water run~off, as well as by cultivation tools that have been used in diseased spots. If set in high, well drained soil, infected plants mg develop healthy runner plants and grow into a productive field. However, if the soil is low, poorly drained or of a tight, wet nature or if a wet, cool spring follows, the new i patch may grow nicely the first season and then go to pieces early the following Q spring The disease is inactive during the warm part of the year. Hence, in- ] fected patches often arc- vigorous and liealtliy looking during the suninier. This condition prevailed in a three-acre ficlcl of Blakenwores in the Pac1ucahl{evi1 section in 1947 and the entire crop was lost except. on a high ridge down the center of the field. Symptoms: The trouble usually becomes noticeable just before harvest. The sympt_o_rris_a_1Te low, small, light foliage that often wilts as the berries try to ripen. These symptoms usually occur first in the lower parts of fields. in little draws. dips or depressions. Most of the foliage scorches on seriously infected plants and the berries do not mature or are seedy and of very low quality. I\/lost of the infected plants continue to lose vigor and die out. The disease can be identified easiest by carefully digging suspected plants and splitting the roots lengthwise. In diseased plants the central core (or stele) of the roots is a dark red or copper color. This corresponds to the appearance of the lead in a pencil split lengthwise. Control measures: At present the best control seems to be to avoid the disease, if possible, This can be done, to a large extent by setting only clean plants that have come from inspected fields. Use higher, well-drained soil V as far as possible, especially after the disease has become established on the l farm. Setting berry plants on small ridges has proven helpful in infected areas. _ Lay out the berry rows so as to encourage good surface water drainage but, of course, still attempt to reduce erosion. Keep new settings of berries out of infected fields for at least five years, since the disease remains in the soil for