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Stephanie G. Harvey and Carl E. Sams

Isothiocyanates are volatile chemicals produced by damaged tissues of Brassica species. Allyl isothiocyanate (AITC), the predominant isothiocyanate in Indian mustard (B. juncea), has been shown to control pest in laboratory and field experiments. We investigated the effectiveness of AITC against the germination of sclerotia of Sclerotium rolfsii Saccardo, a common soilborne pathogen of tomato. Sclerotium rolfsii was cultured on PDA from a field isolate. Mature sclerotia were collected and placed in polyester mesh bags. Culture tubes (16 × 150 mm) were packed with 18 g clay loam soil. A sclerotia-bag was placed in each tube and covered with an additional 5 g soil. Soil was maintained at 60% field capacity for the duration of the experiment. AITC was injected into each tube through a septum. Treatments consisted of 0, 5.6, 11.2, 22.4, and 44.8 μmol AITC/L of atmosphere and an ethanol control. AITC in each tube was sampled using SPME and analyzed on GC-MS. Tubes remained sealed for 42 h at 30 °C. Sclerotia were then removed from tubes and bags and plated on PDA to determine viability. Radial growth was measured to determine the effects of AITC. Mycelial growth was negatively correlated to AITC concentration (P < 0.01). The highest concentration of AITC resulted in a 40.3% reduction in mycelial growth. Although the AITC concentrations used in this study did not kill sclerotia of S. rolfsii, they did suppress mycelial growth from germinating sclerotia. At higher concentrations, or mixed with other chemicals, AITC may prove to be an affective control for this pathogen.

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Merilark Padgett and Janice C. Morrison

Grape berries (Vitis vinifera L., `Thompson Seedless') exuded a variety of compounds through the cuticle and epicuticular wax layer onto the berry surface. The composition of the exudate changed through the course of the growing season. Phenolic compounds and malic acid were in relatively high concentrations in grape berry exudates after bloom, but were low in exudates from mature fruit. The rate of decrease of phenols and malic acid was more rapid during the early stage of berry growth than during the ripening period. Sugar and potassium concentrations in the berry exudates were low at bloom, but increased rapidly in the later stages of ripening. Water extracts of berry exudates contained sugars, malic acid, potassium, and sodium. The water extracts promoted mycelial growth of Botrytis cinerea Pers. Ethanol and ether extracts contained phenols and lipids. These fractions from fruit sampled in the first 3 weeks after bloom strongly inhibited mycelial growth. The inhibitory effect of these fractions decreased later in the season.

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Jiaqi Yan, Megan M. Dewdney, Pamela D. Roberts and Mark A. Ritenour

CBS lesion development on ‘Valencia’ orange fruit. The effects of heat treatments on mycelial growth of G. citricarpa in vitro and the potential changes in fruit quality caused by hot water treatments were also investigated. Materials and Methods

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Naveen Hyder, James J. Sims and Stephen N. Wegulo

binding materials that hold the fibers together in the husk ( Zachariah and Muralidharan, 2002 ). Evaluation of mycelial growth of P. capsici on medium amended with a coir suspension. Seventy-two grams of dry coir was soaked in 1 L of distilled water and

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Charles S. Krasnow and Mary K. Hausbeck

Institute, Cary, NC) was used to analyze data from the study. Mycelial growth-inhibition data were analyzed with linear regression in PROC REG. The EC 50 and EC 90 were interpolated from growth inhibition data. Growth inhibition data were transformed to

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Charles S. Krasnow, Rachel P. Naegele and Mary K. Hausbeck

based on mycelial growth and percentage of the fruit infected using a 0 to 4 scale adapted from Meyer and Hausbeck (2013) with 0 = no visible pathogen growth, 1 = water soaking only, 2 = light visible mycelial growth, 3 = moderate mycelial growth, 4

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Fahrettin Goktepe, Teresa Seijo, Zhanao Deng, Brent K. Harbaugh, Natalia A. Peres and Robert J. McGovern

noted. Isolates were frozen at –80 °C in 20% glycerol for long-term storage. Temperature effect on mycelial growth in vitro. The optimal temperature for mycelium growth of nine F. solani isolates (04-01, 04-02, 04-03, 05-19, 05-20, 05-253, 05

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Xiaoyuan Feng, Baogang Wang, Wensheng Li, Lei Shi, Jiankang Cao and Weibo Jiang

a microscope with 40× magnification. Germination was determined by observing the conidia directly with a light microscope. Colony diameter of mycelial growth was measured. Data were expressed as percent of conidia germination or mycelial growth

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Mohammed B. Tahboub, Soumaila Sanogo, Paul W. Bosland and Leigh Murray

features usable in breeding programs intended for developing resistance to P. capsici . In laboratory experiments, Beard (2006) showed that mycelial growth of P. capsici was reduced by 49% to 83% on media amended with Capsicum oleoresin varying in heat

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Lisa Keith, Tracie Matsumoto, Kate Nishijima, Marisa Wall and Mike Nagao

, Phomopsis , and Colletotrichum spp. were identified based on morphological and physiological characteristics and on literature reports ( Farungsang et al., 1994b ; Nishijima et al., 2002 ). Temperature effects on mycelial growth. Five replicate, 10-cm