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To our knowledge, reports of Betula spp. resistance against damage caused by the birch leafminer, Fenusa pusilla (Lepeletier), have not been published. Becker (1938), Friend (1933), and Johnson and Lyon (1976) We examined leaves under a microscope at 15 X to ensure that no leafminer eggs were present. All leaves, except 2 or 3 young leaves (5 to 15 mm maximum width) per branch tip were removed and the branch tips were placed in 125 ml Erlenmeyer flasks containing water. Cotton was placed in the neck of each flask to hold branch tips upright and prevent adult leafminers from contacting the surface of the water. Leafminer adults up to 18 h old, reared from late instar larvae were confined to leaves using 10.2 cm diameter x 20.3 cm long sections of cellulose dialysis tubing as cages. The tubing was sealed to the neck of the flasks with tape and, after adults were introduced, sealed at the top by twisting. Tests were conducted throughout the summer as young leaves and leafminer adults became available. Each test consisted of 3 replications for a tree species with 6 to 9 young leaves (3 branch tips) per replicate. Test conditions were 16 h of light at 15" to 20°C, B. populifolia leaves were used as a susceptible standard in all tests. Normally two females were used per leaf with an equal number of males. In several tests, five or 20 females were used on B. davurica. B. populifolia and B. davurica were tested 5 times throughout the summer; B. pendula forma Dalecarlica, B. nigra, and B. alba were tested once. After adults had died (3 or 4 days after introduction) leaves were examined at 15 X with transmitted light.At Geneva, 0,0.35, 0.75, 0.25, and 0.50% of the leaves of B. davurica were darnaged by birch leafminer compared with 3 1,48,20,30, and 27% of the leaves of B. pendula during the respective five seasons. At Dansville, averages of 64% of the leaves of B. populifolia, 52% of B. pendula forma Dalecarlica, and 60% of B. nigra were damaged. Damage to B. davurica was consistently less than damage to B. pendula. Results from Dansville indicate equal susceptibility among the three species observed. In our laboratory tests, regardless of numbers of adult females used, no eggs were deposited in B. davurica and no evidence of attempted oviposition was observed. The average number of eggs deposited by two females per leaf for all other species of Betula tested ranged from

The economic importance of potato leafhopper, Empoasca fabae (Harris), damage to alfalfa in eastern North America is well recognized (Davis and Wilson 1953;Jewett 1929;Kehr et al. 1975;Poos and Johnson 1936;Smith and Medler 1959) and the importance of germplasm that may contribute to development of leafhopper resistant cultivars is obvious. From United States Regional Plant Introduction Station Annual Reports we selected 70 Medicago introductions that were noted as having some resistance against potato leafhopper damage. Reported are the results of field tests conducted to determine the relative resistance of selected introductions. Materials and Methods

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A walk‐in drying room was constructed to remove field moisture from forage legume and grass harvested for seed. Steam at 48–50 p.s.i. was used as a heat source. The heat was transferred from thin coils to a moving air stream. Air flow was forced up or down through bags of drying plant materials. The temperature of the moving air may be adjusted, and there were 10 settings of circulation from completely recirculated air to completely exhausted air after a single cycle. Performance of the drying room was evaluated by drying 96 alfalfa (Medicago sativa L.) plants that had been separated into three components: tops, crowns, and roots. The initial moisture content was highest in the tops, intermediate in the crowns, and lowest in the roots. With the room operating at 43.5 C and with completely recirculating hot air, the tops dried most rapidly, crowns dried at an intermediate rate, and roots dried more slowly than either tops or crowns. At the end of 96 hours all three plant parts were equal in retained moisture content, and at 144 hours loss in weight had completely ceased and all three plant parts had attained stable dry weight.