ProMED
http://www.promedmail.org

Source: Jordan News [summ. Mod.DHA, edited]
https://www.jordannews.jo/Section-109/News/80-of-potato-farms-in-the-Jordan-Valley-affected-by-fungal-disease-34647

The Jordan Farmers Union (JFU) has sounded the alarm regarding the potential for "complete loss or substantial reduction" in potato yields in Jordan from mid-March until May 2024 due to the fungal disease late blight. Already, farmers in the Jordan Valley have incurred severe losses. Over 1000 hectares [2471 acres] have been affected.

Late blight has resurfaced in Jordan after a prolonged absence. Previously manageable, the disease now threatens significant areas of potato farms. Recent weather conditions have created highly favourable conditions for the spread of late blight. Nearly 80-90 percent of potato farms in the Jordan Valley have been affected by the disease. Disease incident in individual potato crops ranges from 30-80 percent.

Despite employing pesticides, farmers have been unable to halt the spread of the disease. Labor shortages have exacerbated the situation, reducing pesticide applications. The Ministry of Agriculture has initiated laboratory tests and aims to implement necessary measures. The agricultural sector faces an uphill battle in navigating the impact of this devastating disease.
--
Communicated by:
ProMED

[Late blight of potato (PLB) and tomato is caused by the fungus-like organism (oomycete) _Phytophthora infestans_ and can cause 100% crop loss. The pathogen can also affect some other solanaceous crops. In potato, it affects leaves as well as tubers; in tomato, it causes lesions and rotting of leaves, stems, and fruits. The disease is favoured by cool, moist conditions. It can spread rapidly within a crop and destroy it within a few days. Under favourable conditions, epidemics in tomatoes may be even more rapid than in potatoes.

The pathogen is spread by plant material (including potato seed tubers, tomato transplants, plant debris, volunteer crop plants), mechanical means (including human and insect activities), wind, and water. Disease management requires an integrated approach; it may include removal of pathogen reservoirs, crop rotation, preventative fungicide treatments of planting material, as well as fungicide sprays of crops. Farm saved or uncertified seed tubers have often been reported as sources of PLB outbreaks. Certified clean planting stock and management strategies for fungicide resistance of the pathogen are considered vital to control late blight outbreaks. Commercial crop cultivars vary in susceptibility to late blight. Development of resistant cultivars is being counteracted by the adaptability of the pathogen.

Late blight is considered an increasing problem worldwide. Considerable variation in aggressiveness between different pathogen strains has been observed, but more virulent strains are emerging frequently. The presence of both A1 and A2 mating types of the pathogen increases the chances of strains with additional fungicide resistances and increased yield losses developing.

Pictures
Late blight on potato:
https://onvegetables.com/wp-content/uploads/2018/08/Potato-late-blight-No-halo.jpg,
https://www.thompson-morgan.com/static-images/tandm/static-articles/how-to-stop-potato-blight/what-is-potato-blight.jpg and
https://farm1.static.flickr.com/81/281344513_74bbffe5fe.jpg
Late blight on tomato:
http://ipm.illinois.edu/ifvn/volume15/images/tomato_late_blight.jpg
Microscopy of PLB infected cells:
https://micro.magnet.fsu.edu/optics/olympusmicd/galleries/brightfield/images/potatoblight.jpg

Links
Information on late blight:
https://gd.eppo.int/taxon/PHYTIN (with photo gallery),
https://doi.org/10.1079/cabicompendium.40970,
https://cropscience.bayer.co.uk/threats/diseases/potato-diseases/late-blight/,
https://cipotato.org/press_room/blogs/combating-late-blight/,
https://www.gov.mb.ca/agriculture/crops/plant-diseases/print,mgmt-late-blight-potatoes.html and
https://www.hutton.ac.uk/research/departments/cell-and-molecular-sciences/epidemiology
_P. infestans_ taxonomy and synonyms:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=232148 and
https://www.speciesfungorum.org/GSD/GSDspecies.asp?RecordID=232148
- Mod.DHA]