Black leg of seedlings

Pythium affects roots, in particular those of seedlings. Infected plants lag in growth. Seedlings fall over (‘ damping-off ’). In slightly older plants [...] General Pythium is considered a ‘weak pathogen’, meaning that it can usually only affect plants that are in a sub-optimal condition or suffer from stress [...] turn yellow, for example in flower bulbs. At first, the plants recover during the night, but later the plants wilt irreversibly. In potted plants the flower

Early blight

General The only known stage in all Alternaria species is the asexual stage. Conidia and mycelium overwinter in the soil and on crop residues and cause [...] are wet. Small differences in optimum temperature occur between species, but in general the risk of Alternaria infection is larger under quite warm and [...] sporulation within five days. Infection is both direct and through wounds and stomata. Spores are dispersed by wind and in some species through the splash of

Brown root rot, corky root rot

lycopersici survives in the soil and in buried tomato roots as microsclerotia. The microsclerotia germinate and produce mycelium that in turn infect the roots [...] horizontal bands on the roots with lengthwise cracks. No discoloration is present in the xylem tissues which distinguishes it from wilts caused by Verticillium [...] cultivation practices. However, this fungus is a poor competitor against a balanced microbial population in soil. How to prevent Brown root rot, corky root

Leaf stripe

graminea is monocyclic, which means there is only one disease cycle during the cropping season. The fungus is seed-borne and this systemic infection is the [...] the seed before use Use resistant cultivars Delay sowing in spring barley until soil temperature is higher than 12-15 o C Prevent plant diseases by optimizing [...] General Pyrenophora graminea is a disease of Barley that causes significant yield losses. Damage symptoms Symptoms first occur on the first, second and

Grape downy mildew

primarily as oospores in fallen leaf litter, though in milder climates it can also persist as mycelium within infected buds and canes. In spring, oospore g [...] grapevine downy mildew, caused by Plasmopara viticola , is one of the most important diseases in wine and table grape production worldwide. The disease [...] on temperature and humidity), the disease is often well-established before it can be visually detected in the field. Leaf symptoms Yellowish to light-green

Cottony soft rot

Sclerotinia sclerotiorum ) overwinters as sclerotia and mycelium in dead and living plant material in or on the ground. Sclerotia germinate at temperatures between [...] whereas the ascospores infect the above-ground plant parts. In greenhouses, usually only mycelium is produced by the germinating sclerotia. The fungus grows [...] General Sclerotinia sclerotiorum, also known as cottony soft root, is a plant pathogenic fungus. It has a very wide range of host plants. Damage symptoms

Potato aphid

the dorsal surface. In green individuals, this stripe is dark green, while in pink specimens it is dark red. This longitudinal stripe is specifically cha [...] aphid ( Macrosiphum euphorbiae ) is of North American origin, but is these days distributed throughout the world. It is a highly polyphagous species with [...] As a result, the plant’s growth is retarded giving rise to deformed leaves or, if the infestation occurs early enough in the season, the death of young

Green peach aphid

peach tree, is native, however it is now a pest with a world-wide distribution. The green peach aphid ( Myzus persicae subsp. persicae ) is a particularly [...] General The green peach aphid ( Myzus persicae subsp. persicae ) is an important insect pest in sweet pepper, tomato, cucumber and many other greenhouse crops [...] persicae subsp. persicae ) is the most important vector of viral diseases. It can transmit at least 100 different viruses and is thus rightfully feared by

Glasshouse potato aphid

to deformations in the growing tip of the plant. Precisely where the plant is pierced is unimportant. The piercing of the lower leaves in the crop can cause [...] presence in the crop. The wingless adult stage of the greenhouse potato aphid is rather squat, of medium size (1.8 - 3.0 mm long) and oval in shape. It [...] that has pale to dark transverse bands. The body shape is similar to wingless females, but is 2.0-3.0 mm long. The glasshouse potato aphid manifests both

Grapevine powdery mildew

(Erysiphe necator) is closely synchronized with the vine growth stages and environmental conditions. Understanding its lifecycle is essential to implementing [...] buds or as chasmothecia (sexual fruiting bodies) attached in the bark crevices and plant debris. In spring, chasmothecia release ascospores during periods [...] Grapevine powdery mildew (Erysiphe necator) is a widespread fungal disease that poses a serious threat to commercial viticulture worldwide. The pathogen