Hannah Jones1, John M. Whipps2, and Sarah Jane Gurr1
1 Department of Plant Sciences, South Parks Road, University of Oxford, Oxford, OX1 3RB, UK,
2 Horticulture Research International, Wellesbourne, Warwick, CV35 9EF, UK
| Summary: | Powdery mildew fungus; Ascomycete although sexual stage is yet to be found; an obligate biotroph. |
| Identification: | Superficial mycelium with hyaline hyphae; unbranched erect conidiophores; conidia, ellipsoid-ovoid or doliform, 22-46 x 10-20 痠, lack fibrosin bodies; conidia formed singly, rarely in short chains of 2-6 conidia; appressoria lobed to multilobed, rarely nipple-shaped. Pseudoidium species. |
| Host range: | Broad, reported to attack over 60 species in 13 plant families, particularly members of the Solanaceae and Curcubitaceae. |
| Disease symptoms: | Powdery white lesions on all aerial plant parts except the fruit. In severe outbreaks the lesions coalesce and disease is debilitating. |
| Agronomic importance: | Extremely common in glasshouse tomatoes world wide but increasing in importance on field grown tomato crops. |
| Control: | Chemical control and breeding programmes for disease resistance. |
