Herbicide Symptoms - Part 1 (ACIS)

Classical photosynthetic inhibitors - block the light reactions of photosynthesis and result in the formation of toxic singlet oxygen and/or lipid radicals. The result is lipid peroxidation, destruction of membranes, leakage of cell contents and desiccation and death.

Symptoms include interveinal (most triazines) or veinal chlorosis (phenylurea) or general chlorosis of leaves and yellowing of leaf margins followed by necrosis in affected areas.

Triazine herbicides

atrazine - Aatrex,Atrazine
prometon - Pramitol, various trade names
prometryn - Caparol, Prometryn
simazine - Princep, Simazine
metribuzin - Sencor

diuron - Direx, Diuron, Karmex,
fluometuron - Cotoran, Meturon
tebuthiuron - Spike

Full Disclaimers

Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, James A. Christenson, Director Cooperative Extension, College of Agriculture, The University of Arizona.

The University of Arizona is an equal opportunity, affirmative action institution. The University does not discriminate on the basis of race, color, religion, sex, national origin, age, disability, veteran status, or sexual orientation in its programs and activities.

Because labels are subject to frequent change, always consult the label attached to the product before using any pesticide. The user must assume responsibility for proper application and for residues on crops as well as for damage or injury caused by pesticides, whether to crop, person or property.

Any products, services, or organizations that are mentioned, shown, or indirectly implied in this web document do not imply endorsement by The University of Arizona.

Erin Taylor, etaylor@cals.arizona.edu Extension Agent, Field & Veg Crops
William B. McCloskey, wmcclosk@ag.arizona.edu Extension Weed Specialist
College of Agriculture, The University of Arizona, Tucson, AZ.
Material written June 2003.