Onion fly

applying chemical insecticides when necessary. Damage caused by onion fly Severe onion fly damage can cause stunted growth, yield reduction or even death of [...] spotting an infestation early can help stop the insect from spreading and causing more harm. Biological control of onion fly with nematodes Biological control

Pea blight, leaf and pod spot

and thus also causes post- and pre-emergence damping off and dwarfing. Other Ascochyta species may also infect peas. Ascochyta pinodes causes Ascochyta blight [...] blight, which causes darker spots than Ascochyta pisi . Ascochyta pinodella (current preferred name Phoma medicaginis var. pinodella ) causes foot rot in [...] General Ascochyta pisi is a fungal plant pathogen that causes A scochyta blight on pea (leaf blight or pea blight) and lesions of stems, leaves, and pods

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

Verticillium wilt

pathogens. Verticillium dahlia causes verticillium wilt and early dying of potato. Damage symptoms Verticillium species mostly cause wilting of plants. The wilting [...] The presence of both the fungus and the gum causes the xylem vessels to get blocked, which in turn causes the plant to wilt. Spores may be wind-dispersed [...] vessels, brown or greenish, but much less distinct than the discolouration caused by Fusarium . The root system usually stays mostly intact. In rose, branches

Fusarium spp.

(FSSC) are capable of causing disease in many agriculturally important crop 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 [...] /Gibberella zeae ( Fusarium head blight or scab ) (anamorph/teleomorph) causes seedling damping-off . On the foot of the stem, brown discolouration occurs

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

Apple scab

Venturia inaequalis is an ascomycete fungus that causes apple scab disease Damage symptoms Venturia inaequalis causes apple scab disease, which at first presents [...] lesions become grey and fluffy. The lesions caused by ascospores are more restricted, whereas the lesions caused by conidia extend faster and may merge. Infected [...] then grow between the cuticula and the epidermis of the plant cells. This causes lesions, on which conidiophores, structures which carry conidia, are formed

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