Psyllid yellows is a disease of

potato The potato is a starchy food, a tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial in the nightshade family Solanaceae. Wild potato species can be found from the southern Unit ...

es infested by the potato/tomato

psyllid Psyllidae, the jumping plant lice or psyllids, are a family of small plant-feeding insects that tend to be very host-specific, i.e. each plant-louse species only feeds on one plant species (monophagous) or feeds on a few closely related plants ( ...

, ''

Bactericera cockerelli ''Bactericera cockerelli'', also known as the potato psyllid, is a species of Psylloidea, psyllid native to southern North America. Its range extends from Central America north to the American Pacific Northwest and parts of Manitoba, in Canad ...

''. The symptoms are a marked yellowing of the leaves, an upright appearance to the leaves, with severe cases resulting in early death of the plant. Tuber initiation and growth is affected. Many small tubers are formed, frequently misshaped. In some cases, the tubers seem to have lost sprouting inhibition and have begun sprouting before harvest. At later stages, the tubers sprout weakly, if at all. It is thought that a toxin produced by the nymph stage of the

causes these symptoms. If pest control occurs at an early stage of the disease, the plants appear to be able to recover. A very similar disease has been described in tomatoes. In addition to the foliar symptoms, mature fruit is very much smaller, tends to have a pointy end, and frequently they occur in larger clusters of fruit than normal. In severe cases, the yellowing progresses to plant death. In addition to psyllid feeding, a new species of bacterium

Candidatus In prokaryote nomenclature, ''Candidatus'' (Latin for candidate of Roman office) is used to name prokaryotic phyla that are well characterized but yet-uncultured. Contemporary sequencing approaches, such as 16S sequencing or metagenomics, provide m ...

'' Liberibacter solanacearum' has been associated with this disease.

Capsicum ''Capsicum'' () is a genus of flowering plants in the Solanum, nightshade family Solanaceae, native to Americas, the Americas, cultivated worldwide for their chili pepper or bell pepper fruit. Etymology and names The generic name may come f ...

crops show a similar fruit effect, but generally with no, or very little, foliar symptom. A summary of symptoms from plants in New Zealand with photos of tomato and capsicum plants: * Symptoms in tomato plants: Include leaf curling and yellowing stunting of the plant, fruit occasionally misshapen with a strawberry like appearance. The leaf axial or stalk may also become very long and the fruit development may be uneven. * Symptoms in capsicum plants: Include pale green or yellow leaves with spiky tips. Leaves may be misshapen. Leaf stalks may be misshapen, leaf stalks appear short, flowers may drop prematurely and parts of the plant may die back. Symptoms may vary in severity between varieties. * Symptoms in potato tops can include these being smaller than normal, yellowing and the tops can develop a scorched appearance before premature collapse. This same Liberibacter has recently been found in potatoes in New Zealand and in the US.Candidatus Liberibacter spp. as putative causal agent of Zebra Chip of potatoes
/ref> The potato disorder/disease "

Zebra chip Zebra chip, also known as ''papa manchada'' and ''papa rayada'', is a disease in potatoes putatively caused by an alphaproteobacteria "''Candidatus'' Liberibacter solanacearum", which is vectored by the potato psyllid. When fried, potato tubers ...

" is related in that

'' Liberibacter solanacearum' has been reported from Zebra Chip potatoes in both Texas and New Zealand.

References

{{reflist Bacterial plant pathogens and diseases Potato diseases Candidatus taxa