Bacterial blight develops on the upper leaves of during periods of cool, wet weather, after the plants have reached the boot stage. Leaf blight is associated with high relative humidity, wet weather, and cool spring temperatures (15-25 degrees C or 60-75 degrees F). Warm, dry weather stops the disease and new emerging leaves may be relatively free of bacterial infection. Although detailed studies have not been conducted, damage to the flag often occurs suggesting that yield losses may reach 10-15%. Disease incidence and severity is reducing by rotating to non-grain crops, burying crop residue and using disease free seed. No resistant cultivars are known, some are more susceptible than others. Jan Keizer (referee)  Johannes "Jan" Nicolaus Ignacius Keizer (born October 6, 1940 in Volendam, North Holland) is a retired Dutch referee. He is known for having refereed two matches in the 1986 FIFA World Cup in Mexico. He also refereed one match in the 1984 UEFA European Football Championship in France. Keizer is known to have been a FIFA referee during the period from 1974 to 1987. He officiated the final at the 1984 Olympic tournament between France and Brazil, and served as a referee in the 1983 FIFA World Youth Championship, UEFA Euro 1980 qualifying, UEFA Euro 1984 qualifying, UEFA Euro 1988 qualifying, 1978 FIFA World Cup qualification, 1982 World Cup qualification, and 1986 World Cup qualification. Prestwich tram stop  Prestwich tram stop is a stop on the Bury Line of Greater Manchester's light rail Metrolink system. The stop was originally Prestwich railway station, which was along the Manchester to Bury heavy rail line, completed by the Lancashire & Yorkshire Railway, in 1879 and opened on 1 September. The line was converted from steam to electric power as from 17 April 1916, using the third rail system. The station closed on 17 August 1991 to allow conversion of the route to the Metrolink system using overhead power lines, reopening on 6 April 1992. The station forms part of Ticketing Zone B. It is located off Rectory Lane a walkway connects the station to the Longfield Suite Precinct and Bury New Road (A56). Services mostly run every 12 minutes on 2 routes, forming a 6-minute service between Bury and Manchester at peak times. Cumfybus service 484 runs to Eccles and Manchester Community Transport service 90 to the nearby Tesco stops outside the station. On Bury New Road, which is on the opposite side of the shopping centre, First services 92, 93 and 98 run between Bury and Manchester (92 via Unsworth, Hollins and Pilsworth, 93 via Unsworth and 98 via Whitefield and Radcliffe), along with Maytree's 95 service between Bury and Pendleton and 495 service to Simister.