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Jayesh B. Samtani, John B. Masiunas, and James E. Appleby

growth stage influenced visual leaf injury (1 = no injury to 10 = plant dead) at 45 d after treatment at the leaf unfolding stage. Acetochlor concentrations were 20 (1%) and 500 (25%) g·ha −1 . Bars with the same letter are not significantly different

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M.E. Conley, J.C. Pair, and E. T. Paparozzi

During 1989, leaves of 3 cultivars of Acer saccharum were sampled from a cultivar trial. The purpose was to anatomically investigate development of leaves and incidence of foliar injury due to tatter. Previously, certain cultivars had been observed to be more predisposed to tatter than others. However, more injury symptoms than just tatter occurred. An extensive literature search revealed that definitions for each type of injury varied and often conflicted.

In this poster, photographs of various injuries plus the terms and definitions deemed most representative of what was observed will be presented. Terms explored will include tatter, windburn, sunburn, scorch and scald. Also, a separate symptom which may prompt creation of a new term. will be presented. This injury appears to be part of, but could be separate from, the etiology of leaf tatter. This new term must be considered carefully as preliminary results suggest that tatter does appear to be linked to anatomical differences among cultivars. A questionnaire soliciting opinions/reactions to the confusion in the literature, these terms, and the new term(s) will be featured. Hopefully, this will help resolve the leaf injury nomenclature dilemma.

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Thomas M. Kon, Melanie A. Schupp, Hans E. Winzeler, and James R. Schupp

fertilization of later blossoms and spur leaf injury is minimal. The purpose of this work was to determine 1) effects of TS treatments on the duration of stigmatic receptivity, 2) effects of TS temperature and timing on pollen tube growth in vivo and visible

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Thomas M. Kon, Melanie A. Schupp, Hans E. Winzeler, and James R. Schupp

strategy, the effects of TS temperature and treatment duration on pollen tube growth in vivo and visible spur leaf injury were evaluated. Materials and Methods Trials were conducted in 2014 and 2015 at the Pennsylvania State University’s Fruit Research and

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W. Mersie, T. Mebrahtu, and M. Rangappa

Plant introductions of Phaseolus vulgaris L. were grown from seed in a growth chamber and exposed to 0, at 0.6 μl·liter-1 for 2 hours. Plants were assessed for their response to O3 by evaluating percent leaf injury. Of the 410 introductions tested. 17 insensitive. 370 sensitive. and 23 highly sensitive plant introductions were identified.

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Leonardo Lombardini, Astrid Volder, Monte L. Nesbitt, and Donita L. Cartmill

leafminer as a function of measured leaf area injured; A = 10.317 – 2.0238 × ln(% leaf injury), P < 0.001 (n = 40). Fig. 2. Net photosynthesis rates (A uninjured ) ( A ) and PSII maximum efficiency (F v ′/F m ′ uninjured ) ( B ) of non-injured portions of

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J.G. Clapp Jr.

Urea-triazone-based nitrogen (N) solutions were evaluated for potential leaf injury on agronomic and horticultural crops at 61 commercial grower sites throughout the United States. Poliar spray solutions containing triazone N were used at concentrations ranging from 1.5% to 15.7%. Safe N concentrations for urea-triazone-based N products ranged from 1.5% for crops such as sweet corn, apple, cherry, and pear, and up to 15.7% for nursery root stocks. Urea-triazone-based N solutions were found to be much safer on crop foliage than ammonium-, nitrate-, and/or all urea-based foliar fertilizer products than reported in the literature.

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Abbas Lafta, Thomas Turini, German V. Sandoya, and Beiquan Mou

one germplasm accession) were selected through a preliminary screening of more than 1000 genotypes for leaf injury, fresh weight, and survival of seedlings at 43 °C day/35 °C night for 12 h in a growth chamber. The putative heat-tolerant genotypes

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Robert M. Welker, Richard P. Marini, and Douglas G. Pfeiffer

White apple leafhopper (WALH; Typhlocyba pomaria McAtee) feeding damage on apple (Malus domestica Borkh.) leaves was examined with scanning and transmission electron microscopy. WALH created feeding holes in the (lower) abaxial epidermis, with no visible exterior evidence of cell injury to the adaxial (upper) epidermis. Feeding holes were located in areas of the leaf with high stomatal density and were near stomata. Groups of cells in the palisade layers were empty or contained coagulated cell contents. Adjacent, apparently noninjured, palisade cells contained an abundance of starch granules, possibly indicating that photoassimilate export was impaired. Spongy mesophyll cells abaxial to the feeding area were left intact as were the epidermal cells adaxial to the feeding area. External views of either epidermis and internal leaf views of injured cells indicated no cell wall collapse.

Open access

D. C. Ferree and F. R. Hall


Various treatments resulting in physical stress to leaves of apple (Malus domestica Borkh.) were tested for their influence on net photosynthesis (Pn) and transpiration (Tr). Brushing to simulate handling or wind rubbing reduced both Pn and Tr in one study and had little effect in another. Shaking 1 min/day had no influence on Pn or Tr. Six or more 1-cm cuts/leaf reduced Pn and had no effect on Tr. Removal of 20% of the leaf area and twenty-four 1-cm cuts/leaf reduced Pn in young expanding leaves; the amount of cut surface exposed by injury was more important than the amount of leaf area removed. Scoring and feeding of two-spotted spider mites [Tetranychus urticae (Koch)] reduced Pn.