Dicamba (3,6‐dichloro‐2‐methoxybenzoic acid) effectively controls many dicotyledonous weeds, but nontarget species such as soybean [Glycine max (L.) Merrill) are susceptible to spray or vapor drift. Field studies were conducted on a Canfield silt loam (fineloamy, mixed, mesic Aquic Fragiudalf) soil to determine the response of ‘Elf’ and ‘Williams’ soybean to dicamba over a wide range of applied rates, and to evaluate the use of dicamba injury symptoms to predict yield reductions. Soybean yield in response to increasing rates of dicamba was described by equations of the form y = Aexp( −bx), where y = yield, A = maximum yield (rate = 0 g ha−1), b is a constant, and x = rate of dicamba applied. Height reduction, seed number ha−1, and morphological symptoms of dicamba injury were useful in assessing yield reduction. Except for Elf soybean treated at the midbloom stage, there was no yield reduction without height reduction, regardless of foliar symptoms. Seed number ha−1 decreased with increasing rates of dicamba and was closely correlated with yield. Yield reductions greater than 10% were indicated by severe morphological symptoms of injury, such as terminal bud kill, splitting of the stem, swollen petioles, and curled, malformed pods. Other foliar symptoms, such as distinctive crinkling and cupping of the terminal leaves, occurred at rates much lower than those required to cause yield reductions.

Four enzyme-containing fractions were separated by ammonium sulfate fractionation of 2-day, postbreaker tomato (Lycopersicon esculentum L cv. Manhattan). The

A low-cost, automatic firmness measuring instrument was developed using commercially available components such as: dial gage, dashpot lowering mechanism, weight sets and probe tips. The details of the assembly and the names of parts manufacturers are given. The instrument is an automated modification of the original P-L Meter developed by Parker and Levin at Michigan State University. The application of the instrument to firmness measurements on cherries and tomatoes is summarized and illustrated with typical results. Tomato studies covered the relationship between firmness and variables such as: fruit size, cultivar type, changes in protopectin content, polygalactu-ronase and cellulase activity. The readings compared favorably with those obtained with the Instron Universal Testing machine.

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Cellulase activity increased with softening of ripening fruit and differed among the tomato lines. Fruit containing genes for high pigment had lower cellulase activity and did not soften as rapidly as the commercial lines.