On a New Damping-Off Disease of Texas Bluebonnets

Abstract

The Texas bluebonnet (Lupinus texensis Hook.) is a native annual plant and the official State fiower of Texas. The plant grows in wooded areas, open prairies, and along railroad banks; and seems to thrive well in calcareous, neutral, and even slightly acid soils. The bluebonnet fiower is showy, and usually lasts a long time on the plants or when placed in water, and is therefore highly prized as a cut fiower. Under field conditions, the plants are very prolific and reseed themselves every year. The seeds usually begin to sprout around January; the plants grow rapidly and are usually in full bloom by March. Bluebonnet plants are very easy to transplant, provided this is done during the month of February, before the plants begin to show fiower buds. Early in January, 1931, Mr. P. B. Monosmith, in charge of the Texas Agricultural and Mechanical College greenhouses, brought in large numbers of plants, which were potted in five-inch pots and placed in a cool house at a temperature of 65? to 70? F. These plants started out well, but before long many of the plants began to lose their normal green color, wilt, and die, and in about ten days the majority of the plants were dead. Microscopic examination of the crowns and roots of these plants showed a typical damping-off and an abundance of Rhizoctonia and Pythium hyphae in the decayed tissues. A number of petri-plate cultures were made from infected crowns and roots, and both the Rhizoctonia and the Pythium were recovered from most of the plants. Microscopic examination of the Pythium showed that it resembled closely P. Debaryanum Hesse. The Rhizoctonia did not produce basidiospores in culture, but its cultural characteristics resembled Rhizoctonia Solani Kuhn 1 Published with the approval of the Director as contribution No. 200, Technical Series, of the Texas Agricultural Experiment Station. 457