Twenty herb species were exposed to root-knot nematode under greenhouse conditions. The root systems were examined for root gall development and nematode reproduction as an indication of host suitability. The herbs evaluated were balm (Melissa officinalis L.), basil (Ocimum basilicum L.), catnip (Nepeta cataria L.), chamomile (Matricaria recutita L.), coriander (Coriandrum sativium L.), dill (Anethum graveolens L.), fennel (Foeniculum vulgare Mill.), hyssop (Hyssopus officinalis L.), lavender (Lavandula augustifolia Mill.), oregano (Origanum vulgare L.), peppermint (Mentha ×piperita L.), rocket-salad (Erurca vesicaria L.), rosemary (Rosmarinus officinalis L.), rue (Ruta graveolens L.), sage (Salvia officinalis L.), savory (Satureja hortensis L.), sweet marjoram (Origanum majorana L.), tansy (Tanacetum vulgare L.), thyme (Thymus vulgaris L.), and wormwood (Artemisia absinthium L.). Peppermint, oregano, and marjoram consistently were free of root galls after exposure to initial nematode populations of two or 15 eggs/cm3 of soil medium and were considered resistant. All other herb species developed root galls with accompanying egg masses, classifying them as susceptible or hypersusceptible to root-knot nematode. The highest initial nematode egg density (15 eggs/cm3) significantly decreased dry weights of 14 species. The dry weights of other species were unaffected at these infestation densities after 32- to 42-day exposure.
Andrew P. Nyczepir, Janete A. Brito, Don W. Dickson, and Thomas G. Beckman
was ended after 114 d (14 July 2006) and the following data were collected: number of egg masses per root system, number of eggs per root system, number of root galls per root system, and dry root weight (dried at 70 °C in aluminum foil until no more
Judy A. Thies, Don W. Dickson, and Richard L. Fery
‘Charleston Belle’ and ‘Carolina Wonder’ exhibited partial loss of resistance when grown at 32 °C for 8 weeks after inoculation with M. incognita , these cultivars had root gall severity indices that were still in the low resistance range, and the number of
Jeffrey Granett, Laszlo Kocsis, Laszlo Horvath, and Eva Baracsi Horvathne
The objective was to explore temporal distribution of grape phylloxera, Daktulosphaira vitifoliae (Fitch), gallicoles on grapevine rootstocks (Vitis sp.) and determine how this distribution arose. We tested the hypothesis that leaf galls are created by individuals arising from the soil in the spring. Galls begin to appear at budbreak and gall averages per leaf increase variably as the season progresses. Initial galling appears to be associated with dry conditions and gall populations decline with rain. Emergence-trap catches show that phylloxera maintain populations on rootstock roots and that these populations disperse above ground. Aerial trap data demonstrated wind dispersal of crawlers and alates. Shielding of canes from soil-emerging phylloxera largely prevented early gall formation. These results suggest alternative testable hypotheses for explaining overwintering of phylloxera in rootstock vineyards.
Charles E. Barrett, Xin Zhao, and Robert McSorley
pest and disease pressure. One of the major pest management challenges is RKNs ( Meloidogyne spp.), which thrive in warm weather and moist, sandy soils ( Roberts et al., 2005 ; Sasser, 1980 ). RKNs cause root galls that damage the root system and
Judy A. Thies, Jennifer J. Ariss, Richard L. Hassell, Sharon Buckner, and Amnon Levi
fibrous roots, where 100% = highly fibrous root system and 0% = no fibrous roots. Nematode eggs were extracted from the roots using 1% NaOCl ( Hussey and Barker, 1973 ) and eggs were counted using a stereomicroscope. Root galling, egg mass, and fibrous
Alexis K. Nagel, Guido Schnabel, Cesar Petri, and Ralph Scorza
ended 60 d after inoculation and the following data were collected for inoculated seedlings: number of egg masses per root system, number of eggs per root system, and fresh root weight. Root systems were also rated for the percentage of root galls
Craig J. Frey, Xin Zhao, Jeffrey K. Brecht, Dustin M. Huff, and Zachary E. Black
after the initial assessment, respectively. A final assessment was conducted after the final harvest on 7 July. Plant root galling ratings were also conducted after the final harvest. In 2016, every other plant in each sub-subplot was assessed. However
Xin Zhao, Qianru Liu, M. Tatiana Sanchez, and Nicholas S. Dufault
fungicides and insecticides following Florida’s watermelon production guidelines ( Elwakil et al., 2017 ; Freeman et al., 2015 ). Assessment of plant growth, pathogen recovery, disease severity, root galling, and fruit yield. The greenhouse experiments were
Kathryn E. Brunson, Sharad C. Phatak, J. Danny Gay, and Donald R. Summer
Velvetbean (Mucuna deeringiana L.) was used in crop rotation to determine the influence on southern root-knot nematode (Meloidogyne incognita) in sustainable vegetable production. Replicated trials were conducted at four locations. Two cover crop treatments, crimson clover and subterranean clover, were used in the sustainable plots and rye was the plow-down cover crop for the conventional plots. Selected as the vegetable crops were tomato, pepper, and eggplant. Following the final harvest, velvetbean was planted into the sustainable plots and disked under after 90 days. Results from soil samples before and after velvetbean, indicated the sustainable plots had substantially reduced nematode densities, while most conventional plots showed increases. A correlation between location, treatment, root-gall indexes and nematode density occurred in all crops for 1992. In 1993 there was only a correlation between root-gall index and nematode density in pepper. However, root-gall indexes were significant for location and treatment in all crops.