Editing Blackcurrant (section)

===Diseases and pests===

''Ribes'' plants are susceptible to several diseases and a number of insect pests. However, new varieties have been or are being developed to overcome some of these problems.<ref>{{cite web |url=http://www.blackcurrantfoundation.co.uk/the_blackcurrant_growing.html |title=Pest and Disease |work=The blackcurrant |publisher=The Blackcurrant Foundation |access-date=2013-09-08 |archive-url=https://web.archive.org/web/20130917165221/http://www.blackcurrantfoundation.co.uk/the_blackcurrant_growing.html |archive-date=2013-09-17 |url-status=dead }}</ref>

[[Cecidophyopsis ribis#Blackcurrant reversion disease|Reversion]] is a serious disease transmitted by the [[blackcurrant gall mite]] (''Cecidophyopsis ribis''). It causes a decline in yield and is quite widespread in Europe but is rarely encountered on other continents. Symptoms include a modification of leaf shape in summer and swollen buds ("big bud") in winter, each housing thousands of microscopic mites.<ref name=Hummer>{{cite web |url=http://www.ars-grin.gov/cor/ribes/ribsymp/stem6.html |title=Black Currant Gall Mite |last1=Hummer |first1=Kim |last2=Postman |first2=Joseph |date=2000-03-01 |work=Currant and Gooseberry Pests |publisher=USDA/ARS [[National Clonal Germplasm Repository]] |access-date=2013-03-09 |url-status=dead |archive-url=https://web.archive.org/web/20120926145635/http://www.ars-grin.gov/cor/ribes/ribsymp/stem6.html |archive-date=2012-09-26 }}</ref> As pest control has limited effectiveness, severely infected bushes should be destroyed. All new plants purchased should be certified as virus-free.<ref>{{cite web |url=http://www.which.co.uk/documents/pdf/blackcurrant-reversion-151472.pdf |title=Which magazine: Blackcurrant reversion |access-date=2012-06-13  |archive-date=2019-08-17  |archive-url=https://web.archive.org/web/20190817171314/https://www.which.co.uk/documents/pdf/blackcurrant-reversion-151472.pdf |url-status=dead }}</ref>

[[White pine blister rust]] (''Cronartium ribicola'') needs two alternate [[Host (biology)|hosts]] to complete its life cycle. One host is plants in the genus ''[[Ribes]]''. On the blackcurrant, it causes the leaves to become pale and later develop tiny orange pustules and sometimes a yellow filamentous coating on some leaves. The fruit crop is little affected but the leaves fall early and growth is slowed the following year. The other host is any of the [[white pine]]s, in which it causes serious disease and mortality for the North American species that have not co-evolved with the rust.<ref name=acornorganic/> As a result, the blackcurrant was [[Blackcurrant production in the United States|banned in the United States]] as a [[Vector (epidemiology)|disease vector]] for much of the 20th century, and even after the federal ban was lifted in 1966, several [[U.S. state]]s continued their own [[Ribes#United States of America|bans]], some of which remain in force as of August 2021. The effectiveness of these restrictions is questionable, since other ''Ribes'' species also host the disease, some are native to North America, and others such as [[red currant]]s and ''[[Ribes uva-crispa]]'' were never banned.{{Citation needed|reason=content needs citation for verification|date=June 2019}}

[[Podosphaera|American gooseberry mildew]] and [[powdery mildew]] can infect the leaves and shoot tips, and [[Botryotinia|botrytis]] may cause the fruit to rot in a wet season. Currant and [[gooseberry]] leaf spot (''Drepanopeziza ribis'') is another disease of blackcurrants, but it is not usually a serious problem as most cultivars now have some resistance.<ref name=Gilbert/>

The blackcurrant leaf midge can cause browning, crimping and distortion of leaves at the tips of shoots but it is seldom a serious problem. The blackcurrant sawfly (''[[Nematus ribesii]]'') lays its eggs on the underside of the leaves and the voracious larvae work their way along the shoots, stripping off leaf after leaf. In a serious attack, the bush can be denuded of leaves. Larvae of the currant borer drill their way along the centres of shoots, which wilt and die back. Other insect pests include [[scale insect]]s, [[aphid]]s and [[earwig]]s.<ref name=acornorganic/>