Fungal pathogenicity in plants requires a conserved mitogen-activated protein kinase (MAPK) cascade homologous to the yeast filamentous growth pathway. How this signaling cascade is activated during infection remains poorly understood. In the soil-borne vascular wilt fungus Fusarium oxysporum, the orthologous MAPK Fmk1 (Fusarium MAPK1) is essential for root penetration and pathogenicity in toma...

Exposing a wild-type culture of Trichoderma harzianum to gamma irradiation induced two stable salt-tolerant mutants (Th50M6 and Th50M11). Under saline conditions, both mutants greatly surpassed their wild type strain in growth rate, sporulation and biological proficiency against Fusarium oxysporum, the causal agent of tomato wilt disease. Tolerant T. harzianum mutants detained a capability to g...

The soilborne pathogen Ralstonia solanacearum is the causal agent of bacterial wilt and causes significant crop loss in the Solanaceae family. The pathogen first infects roots, which are a critical source of resistance in tomato (Solanum lycopersicum L.). Roots of both resistant and susceptible plants are colonized by the pathogen, yet rootstocks can provide significant levels of resistance. Cu...

The use of novel isolates of Trichoderma with efficient antagonistic capacity against Fusarium oxysporum f. sp. lycopersici (FOL) is a promising alternative strategy to pesticides for tomato wilt management. We evaluated the antagonistic activity of 30 isolates of T. asperellum against 4 different isolates of FOL. The production of extracellular cell wall degrading enzymes of the antagonistic i...

Fungal pathogenicity in plants requires a conserved mitogen-activated protein kinase (MAPK) cascade homologous to the yeast filamentous growth pathway. How this signaling cascade is activated during infection remains poorly understood. In the soil-borne vascular wilt fungus Fusarium oxysporum, the orthologous MAPK Fmk1 (Fusarium MAPK1) is essential for root penetration and pathogenicity in toma...

Bacterial wilt caused by Ralstonia solanacearum is the most destructive disease of plants. Fifty-seven isolates of R. solanacearum causing wilt on different host plants viz., tomato (Solanum lycopersicum), brinjal (S. melongena), potato (S. tuberosum), bird of paradise (Strelitzia reginae), ginger (Zingiber officinale), chili (Capsicum annuum), capsicum (Capsicum annuum), davana (Artemisia pall...

The PhcA virulence regulator in the vascular wilt pathogen Ralstonia solanacearum responds to cell density via quorum sensing. To understand the timing of traits that enable R. solanacearum to establish itself inside host plants, we created a ΔphcA mutant that is genetically locked in a low-cell-density condition. Comparing levels of gene expression of wild-type R. solanacearum and the ΔphcA mu...

Verticillium wilt is a vascular disease predominantly caused by the soil-borne fungi Verticillium dahliae and Verticillium albo-atrum. Most of the commercial potato cultivars grown in the USA are susceptible to Verticillium, resulting in significant crop losses. Development of new cultivars with resistance gene(s) against the pathogen can be assisted with molecular marker technology that allows...

Seasonal flight activity of thrips was examined in commercial tomato fields, Lycopersicon esculentum L., on Virginia’s (USA) Eastern Shore in 2000 and 2001. In each of three regions along the Shore, populations of adult thrips infesting tomato flowers and dispersing within tomato fields were monitored weekly. Frankliniella fusca (Hinds) was the only thrips species captured that is currently con...

Tomato spotted wilt virus (TSWV) is transmitted in a persistent propagative manner by Frankliniella occidentalis, the western flower thrips. While it is well established that vector competence depends on TSWV acquisition by young larvae and virus replication within the insect, the biological factors associated with frequency of transmission have not been well characterized. We hypothesized that...