watered with a sprinkler canister daily and fertilized once at the 10-leaf stage with 5N–4.4P–8.3K fertilizer. Plants were monitored for symptoms of Verticillium wilt every 7 d. Verticillium wilt is caused by a soil-borne fungus, Verticillium dahliae . It
using a microscope. Pathogen control (Salinas only) . To evaluate fumigant efficacy for P. ultimum and verticillium wilt ( Verticillium dahliae ), two bags (Forestry Suppliers) per plot containing P. ultimum inoculum and V. dahliae inoculum were
. These included airborne defoliating fungal diseases and verticillium wilt of olives ( Rallo et al., 2013 ). Tests for evaluating resistance to peacock spot ( Fusicladium oleaginum ), cercosporiosis ( Pseudocercospora cladosporioides ), and anthracnose
Abstract
Bacterial wilt (Pseudomonas solanacearum E.F. Smith biovar III) causes substantial losses in susceptible tomato (Lycopersicon esculentum Mill.) cultivars in coastal Queensland from late spring to autumn (3). Verticillium wilt (Verticillium dahliae Kleb. race 1) can be a major disease from autumn to early spring. A previously released cultivar, Scorpio (3), is resistant to bacterial wilt and Fusarium wilt (Fusarium oxysporum Schlecht, ex Fr.f.sp. lycopersici (Sacc.) Snyd. and Hans, race 1), but lacks resistance to Verticillium wilt. Fruit of this cultivar are relatively soft. ‘Redlands Summertaste’ a hybrid, was developed to provide a locally adapted tomato cultivar in which resistances to bacterial, Verticillium and Fusarium wilts are combined with good fruit quality.
Abstract
Susceptible tomato (Lycopersicon esculentum Mill.) cultivars in coastal Queensland may suffer substantial losses from bacterial wilt [Pseudomonas solanacearum (Smith 1896) Smith 1914 biovar III] from late spring to autumn (3). Verticillium wilt (Verticillium dahliae Kleb. race 1) can be a major disease from autumn to early spring. A hybrid cultivar, Redlands Summertaste (1), recently was released and is resistant to bacterial wilt, verticillium wilt, and fusarium wilt [Fusarium oxysporum Schlecht, f.sp. lycopersici (Sacc.) Snyder & Hansen race 1 and 2]. However, although this cultivar has high yields (75 to 92 t·ha–1), the jointed fruit attachment and indeterminate growth habit limit returns to growers who have high labor costs. ‘Redlander’ was developed as an inbred cultivar to provide a locally adapted tomato in which resistances to bacterial, verticillium, and fusarium wilts are combined with good fruit quality, jointless pedicel, and determinate growth habit.
Abstract
Induced resistance to verticillium wilt occurs in fusarium-resistant tomato cultivars from dip inoculation with mixed cultures of Race 1 of Fusarium oxysporum f. lycopersici (F) and Verticillium albo-atrum (V). This induced resistance decreases as F level in mixed inoculi is reduced. Simultaneous screening for resistance to V and F can be achieved by inoculation with V and reinoculating 48 to 72 hours later with F.
Forty-two Lycopersicon pennellii Corr. D'Arcy accessions, from the Tomato Genetics Stock Center, were inoculated for resistance to Fusarium wilt race 3 at the 3-leaf and cotyledon stage. All were over 90% healthy when inoculated at the 3-leaf stage but had greater disease incidence at the cotyledon stage. Crosses were made between healthy plants within each accession. Using this seed, 39 accessions were 100% healthy and 3 were over 96% healthy when inoculated at either stage. Seventeen F1's with susceptible parents were tested for race 3 and all had over 80% healthy plants. Twenty-two accessions were tested for Fusarium wilt race 1 and race 2. For race 1, 21 were 100% healthy and 1 was 91% healthy, For race 2, 20 were 100% healthy, 1 was 96% healthy, and 1 was 75% healthy. Forty accessions were screened for Fusarium crown rot and Verticillium wilt. For crown rot, LA 1277, LA 1367, and LA 1657 were over 95% healthy, 6 other accessions were over 68% healthy and several others had over 50% healthy plants, All 40 were susceptible to Verticillium wilt race 1. L. pennellii appears to be a good source of resistance to Fusarium sp. but not to Verticillium wilt.
Roots of greenhouse-grown mint plants and in-vitro-grown shoot cultures were inoculated with Verticillium dahliae Kleb. conidial suspensions to study wilt symptom development and detection and elimination of the fungus. There were significant differences in the symptom expression between control and infected shoot cultures at all conidia concentrations for the four mints tested. Disease-symptom ratings were proportional to the V. dahliae inoculum density. Infected shoot cultures were stunted when inoculated with ≥ 103 conidia/mL. Verticillium dahliae was re-isolated from infected shoot cultures at all levels of inoculum, but not from any control cultures. Verticillium infections were easily detected by plating mint stems on potato dextrose agar. Shoot tips (0.5 to 15 mm) from infected in-vitro- and greenhouse-grown plants were isolated and screened for fungus. The most effective shoot length for fungus elimination was 3-5 mm. Shoot tips isolated from in vitro spearmint cultivars infected at 102 and 103 conidia/mL were 100% Verticillium free, but only 42% of `Black Mitcham' and 54% of `Todd's Mitcham' peppermints were free of the disease. Shoot tips from infected greenhouse plants produced Verticillium-free cultures from 79% of `Black Mitcham' and 90% of `Todd's Mitcham' plants. These results indicate the utility of testing for Verticillium and the safety of micropropagated mint shoots for certified planting stock programs.
Abstract
‘Tribute’ and ‘Tristar’ are everbearing strawberry cultivars (Fragaria × ananassa Duch.) that fruit in spring, summer, and fall (as indicated by the prefix “Tri-”). They are the first everbearing strawberries bred for culture in the eastern United States which combine resistance to red stele root rot, incited by Phytophthora fragariae Hickman, with a high degree of tolerance to verticillium wilt, incited by Verticillium albo-atrum Reincke & Berth. Their generally consistent good health, productivity, and fruit quality under a number of cultural systems suggest that these cultivars will offer new opportunities to the strawberry home gardener and commercial grower alike.
Strawberry cultivars Selva and Camarosa (Fragaria ×ananassa Duch.) were grown at a high elevation nursery in soil that was either naturally infested with Verticillium dahliae or was rendered pathogen-free through preplant fumigation with 2 methyl bromide: 1 chloropicrin (wt/wt) at 392 kg·ha-1. Plants grown in fumigated soil were inoculated with a conidial suspension of V. dahliae, prior to establishment. Just prior to harvest, plants were rated for disease based on symptoms of Verticillium wilt. At the same time, petiole samples were taken from mother plants and each of three generations of runner plants, along with the stolons subtending each of the sampled runner plants. Petioles and stolons were cultured to assay for the presence of V. dahliae, and scored as either infected or not infected. The experiment was conducted in each of two successive years, and the following conclusions were supported by results obtained in both years. First, symptoms of Verticillium wilt on mother plants of both cultivars were highly correlated with recovery of V. dahliae from petioles, but runner plants were consistently free of symptoms even though they were often infected. Second, runner plants sustained lower infection frequencies than mother plants, with the differences being significant in most cases. Lastly, infection of runner plants was due, at least in part, to transfer of inoculum from infected mother plants; in some cases this appears to have been the exclusive mode of infection.