Crazy roots, hairy roots, crown gall

Rhizobium radiobacter causes crazy roots, hairy roots and crown gall. Damage symptoms The four pathogenic Rhizobium species cause different symptoms, like [...] All four species cause the growth of galls on the stems, which are first white and later turn brown. Only Rhizobium radiobacter causes galls and tumours [...] no bacteria have been isolated from crazy roots. This disease seems to be caused by a change in the hormonal system of the plant resulting from the Rhizobium

Fusarium spp.

(FSSC) are capable of causing disease in many agriculturally important crops Damage symptoms of Fusarium spp. Fusarium fungi cause vascular wilt, root rot [...] post-harvest decay. Fusarium oxysporum ( Fusarium wilt ) is the species that causes vascular wilt. Initially, the leaves turn yellow and wilt, mostly on one [...] graminearum/Gibberella zeae (Fusarium head blight or scab) (anamorph/teleomorph) causes seedling damping-off . On the foot of the stem, brown discolouration occurs

Black rot of carrots

Infection of carrots during post-harvest storage causes dry, sunken, black lesions. Typically, Alternaria causes spots on leaves, petals and stems. These spots [...] stage. Conidia and mycelium overwinter in the soil and on crop residues and cause primary infection of the leaves. Survival can be several years, in the case [...] to 8 years. Damage symptoms Black rot of carrots ( Alternaria radicina ) causes death of seedlings and dark brown lesions with a yellow halo on leaves,

Flies

Lyprauta sp.) can cause damage in potted orchids. The Spotted Wing Drosophila has recently invaded Europe and the Americas where it is causing serious damage [...] in agriculture, horticulture and mushroom cultivation. Species that can cause damage or nuisance, are particularly small flies of the families Sciaridae [...] and prefer moist substrates that is rich in organic matter. Although they cause little direct damage to plants, they are often a problem due to their large

Pepino mosaic virus

the damage that is caused. For instance, an infection early in the season, when the plant does not yet bear fruit, will typically cause less losses than [...] symptoms and the damage they cause. For example, there are very aggressive Chilean isolates, but also very mild ones that cause less symptoms. Pepino mosaic [...] started to damage greenhouse tomato crops in Europe. Although the virus only causes major problems in tomato cultivation, other plants of the Solanaceae family

Early blight

and cause primary infection of the leaves. Survival can be several years, up to eight years for several Alternaria spp. Typically, Alternaria causes early [...] concentric rings that are caused by sporulation. Species may differ in specific symptoms. Damage symptoms Alternaria solani causes small green to dark brown

Leaf miners

miners Leaf miner damage Leaf miners cause damage to plants both directly and indirectly. The most direct damage is caused by the larvae mining the leaf tissue [...] , the larvae of these species are parasitized by parasitic wasps and so cause few problems. However, the use of chemical insecticides kills these natural [...] the biological control of other crop pests. The leaf miner species that cause damage in horticultural crops are mostly polyphagous; that is, they feed

Downy mildew of Cucurbits

General Pseudoperonospora cubensis is a plant pathogen causing downy mildew on cucurbit crops like cucumber, cantaloupe, pumpkin, watermelon and squash [...] pathogens infect mostly the leaves but occasionally also stems and fruits. They cause lesions on the upper leaf surface, bordered by the veins, which are first [...] extruding from the stomata. Life cycle and appearance of Downy mildew Pathogens causing downy mildew are not fungi but Oomycetes and related to Pythium and Phytophthora

Phytophthora blight

potato blight and late / early blight of potato. Damage symptoms Phytophthora causes root rot, seedling damping off and rot of stems, bulbs, tubers, leaves and [...] Late blight or Phytophthora blight (Phytophtora infestans f.sp. infestans ) causes water-soaked lesions with vague borders and white fluffy fungal growth on [...] seen through the skin. The Great Famine was a period of mass starvation caused by this disease which ravaged potato crops throughout Europe during the

Potato/tomato psyllid

potato psyllid amplifies the feeding damage and causes ‘zebra chip’ in potatoes Indirect damage causes the most harm, since the consequences are wide-ranging [...] responsible for serious crop damage, both directly and indirectly, the latter causing the greatest concern and proving difficult to control. In light of this [...] is considered a quarantine pest. Damage symptoms The main direct damage, caused by potato psyllid nymphs when feeding, is known as ‘psyllid yellows’, which