Purple blotch
Alternaria porri
Description
The initial symptoms of purple blotch are small, water-soaked lesions with white centers that appear usually on older leaves. As the disease progresses, the lesions enlarge (individual lesions can be as long as 1–2 inches) and become purplish with light yellow concentric rings on the margins. As severity increases, leaves turn yellow brown, lose erectness, and wilt. Windborne conidia from previous crop debris intiate infection, which is favored by high temperatures and humid conditions. Prolonged leaf wetness increases the probability of further infection.
Pesticides
Acrobat
intensity: ★★★
Acrobat MZ 690
intensity: ★★★
Acrobat SC
intensity: ★★★
Acrobat WDG
intensity: ★★★
Aprisco 900 WG
intensity: ★★★
Axiom MZ 720
intensity: ★★★
Bravo
intensity: ★★★
Bravo Weather Stik
intensity: ★★★
Cavalry Weatherguard
intensity: ★★★
Cherokee 900
intensity: ★★★
Conan 500
intensity: ★★★
Conan 720 SC
intensity: ★★★
Dithane Rainshield Neo Tec
intensity: ★★★
FMC Chlorothalonil 720
intensity: ★★★
FMC Chlorothalonil Bond 720
intensity: ★★★
Frenta 750 WG
intensity: ★★★
Galben M
intensity: ★★★
Manzate DF
intensity: ★★★
Penncozeb
intensity: ★★★
Penncozeb 750 DF
intensity: ★★★
Polyram DF
intensity: ★★★
Ridomil Gold MZ WG
intensity: ★★★
Ridomil Gold Plus
intensity: ★★★
Rotam Aprisco
intensity: ★★★
Rotam Milor 720 WP
intensity: ★★★
Rotam Winner Mancozeb WP
intensity: ★★★
Sphinx
intensity: ★★★
Unizeb Disperss 750 DF
intensity: ★★★
Zeemil 720 WG Systemic and Protective
intensity: ★★★
Zeemil MZB 720 WP Systemic and Protective
intensity: ★★★
Arysta LifeScience Mancozeb 750 WG
intensity: N/A
Barmac Zineb
intensity: N/A
Barrack 720
intensity: N/A
Barrack Betterstick
intensity: N/A
Chlornil 720 SC
intensity: N/A
Chloronil Pro
intensity: N/A
Chlorothalonil
intensity: N/A
Clash Dry 900 WG
intensity: N/A
Clash Storm Guard 720 SC
intensity: N/A
Echo 720
intensity: N/A
Manco 750 WG
intensity: N/A
Mancoflo
intensity: N/A
Mankocide DF
intensity: N/A
Manzeb
intensity: N/A
Maxyl
intensity: N/A
Metal-Man Mz 720
intensity: N/A