Mildew, powdery

An obligate ascomycetes, Erysiphe cichoracearum DC., powdery mildew, can be moderately severe on some Jerusalem artichoke lines in the southern U.S., while others remain essentially disease-free (McCarter, 1993). E. cichoracearum infects a wide range of species, especially so in the Compositae family. It is found worldwide and is especially critical in the hot, humid tropics and subtropics. Damage in temperate regions tends to be limited. The disease appears as white to gray areas on the leaves and occasionally on the stems, which is caused by superficial mycelium. With 

Biology and Chemistry of Jerusalem Artichoke Helianthus tuberosus L. 

Powdery mildew form cleistothecia, the overwintering structures of the organism. Cleistothecia are 90 to 135 pm in diameter and have numerous unbranched appendages. Development of cleistothecia is stimulated by cool weather, and they are seen as black, pinhead-sized dots scattered over the surface of the leaves. Cleistothecia are found on infested stubble, which acts as an inoculum, providing conidia or ascospores that infect new plants the following season. 

In continuous culture, the inoculum progressively builds up in the soil, leading to greater losses each year (e.g., 1% loss in year 1, 19% in year 2, and 22% in year 3 for the cultivar Nahodka ) (Cassells and Walsh, 1995). Control, therefore, is best mediated through rotation with nonhost crops. Since the sclerotia can survive in the soil for up to 7 years, a 3- to 5-year rotation is recommended. Jerusalem artichoke can be rotated with small grains or maize, but not dry edible beans, sunflowers, safflower, mustard, or soybeans — all crops susceptible to sclerotinia wilt. Effective control of weeds, which may act as hosts, and volunteer Jerusalem artichokes is also 

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Karathane A trade name for 2,4-dinitro-6-( 1 -methylheptyl)phenyl crotonate, CJ8H24N2O6, a compound which has both acaricidal and fungicidal activity. It is a red-brown oil of high boiling point, insoluble in water but soluble in most organic solvents. Karathane is used for the control of powdery mildew, and is nontoxic to mammals. 

Ascomycetes Prysiphe graminis powdery mildew of wheat/barley... 

The almost exclusive use of tria2oles foi ceieal powdery mildew control up to the mid-1980s has resulted in a shift in E.Tysiphe populations toward reduced sensitivity or resistance to this class of fungicides. However, use has continued because field performance of most tria2oles has remained adequate (43). Decreased a2ole sensitivity in the population to a2oles has also been noted. 

Profiling of wheat class III peroxidases genes derived from powdery mildew-attacked epidermis reveals distinct sequence-associated expression patterns / / Molecular Plant-Microbe Interactions. V. 18. P. 730-741. 

Mineral Bicarbonate (K and NA) Kaligreen Powdery mildew, black spot, leaf spot Grapes, strawberries Fungicide... 

Copper products Champion, Clean Crop, Nordox Powdery mildew, anthracnose, various blights Various fruits and vegetables Fungicide... 

Soaps Potassium salts of fatty acids M-Pede Aphid, whitefly, mealybug, powdery mildew Various fruits and vegetables Insecticide, fungicide... 

Grapevine vines Powdery mildew Uncinula necator Copper sulphate + sulphur... 

Cucumbers Powdery mildew Erysiphe cichoracearum Bordeaux mixture, copper ammonium carbonate... 

Beans Powdery mildew Erysiphe polygoni Bordeaux mixture... 

Romero-Perez AI, Lamuela-Raventos RM, Andres-Lacueva C and Torre-Boronat MC. 2001. Method for the quantitative extraction of resveratrol and piceid isomers in grape berry skins. Effect of powdery mildew on the stilbene content. J Agric Food Chem 49(1) 210-215. 

Hiickelhoven R, Kogel KH (2003) Reactive oxygen intermediates in plant-microbe interactions who is who in powdery mildew resistance Planta 216 891-902 Hurtado AQ, Critchley AT, Trespoey A, Bleicher-L Honneur G (2006) Occurrence of Polysiphonia epiphytes in Kappaphycus farms at Calagas Is., Camrines Norte, Philippines. J Appl Phycol 18 301-306... 

Thordal-Christensen H, Zhang Z, Wei Y, Collinge DB (1997) Subcellular localization of H202 in plants. H202 accumulation in papillae and hypersensitive response during the barley-powdery mildew interaction. Plant J 11 1187-1194... 

Sulfur Naturally occurring mineral used to control powdery mildew and rose black spot. It can harm predatory mites, so it should not be applied where biological controls are in use. 

Potassium bicarbonate can be used against powdery mildew, black spot, and downy mildew on a range of plants including roses, fruits, and cucurbits. 

Resistant roses Roses are often thought to be terribly prone to diseases, such as black spot and powdery mildew. The trick is not to grow roses all together In a "rose bed," where disease can spread choose resistant roses (see also p.l69) such as Buff Beauty, above, and mingle them in with other garden plants. 

Cucumber mosaic virus pictured on p.89) can, despite its name, affect all members of this family, and many other plant families, too. There Is no cure, but some cultivars show some resistance. Protect young plants from slugs. Powdery mildew may be a sign of dry soil late In the year It will not affect the crop. Under cover, biological controls can be used to control pests like red spider mite. Crop rotation, good... 

Pick off diseased fruit and foliage as seen. Powdery mildew symptoms on leaves are more likely in dry weather. Use a drip or soaker hose watering system to avoid wetting the foliage. 

Fungal disease that overwinters in buds. Infected buds open later than healthy ones. See also Powdery mildews. 

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