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Ministry of Agriculture, Food and Rural Affairs


Trade Name: Aatrex Liquid, Converge 480,

Registration status: This herbicide is not registered for use in tender  fruit orchards.

When to suspect injury: Injury from atrazine may occur when atrazine (or herbicide mixtures like Primextra that contain atrazine), were used on fields before orchards were planted. Atrazine can persist in soil for varying lengths of time depending on rate, weather and soil conditions (see below). If you notice the symptoms described below, ask for a herbicide history of the field and determine the soil pH and organic matter.

Herbicide Information:  Knowing how the herbicide works will help to determine the likelihood of injury from either direct application or drift.  Consider how the herbicide works in plants, behaves in soils and what symptoms are common in other plants.  

Chemical Family : S-triazine

Site of Action/Group:  Inhibition of photosynthesis (WSSA Group 5)

General Symptoms in Plants

  • Interveinal chlorosis of the leaves and yellowing of the margins
  • Older leaves more damaged than new growth
  • Browning of leaf tips
  • Root growth is not affected 

Symptoms in Fruit Trees

  • Interveinal chlorosis in leaves
  • Yellowed leaf margins
  • Brown leaf tips
  • More prevalent on older leaves
  • Trees located in soil where atrazine residues may be high based on previous cropping history

Uptake and Translocation

  • Absorbed by plants mainly through the roots, but also through the foliage
  • Once absorbed, atrazine is translocated upward and accumulates in the growing tips and the new leaves of the plant


  • Can persist in the soil for varying lengths of time, depending on rate applied, weather and soil conditions
  • Persistence is longer under dry, cool weather conditions and in sandy soils
  • Post-emergence treatments tend to persist longer than pre-emergence treatments
  • Many horticultural crops require 10-22 months after applications of 1-1.5 kg ai /ha. before planting
  •  Atrazine is moderately to highly mobile in soils, especially where soils have low clay or organic matter content
  • Half-life in field: 60-100+ days
  • To reduce the hazard of atrazine residues:
    • Fall plowing will reduce triazine injury more than spring plowing
    • Deeper tillage will reduce the concentration of herbicide in the upper soil area compared to shallow tillage
    •  Adjust soil pH to between 6.0 and 7.5
    • Spray uniformly without overlaps, especially along headlands

If you suspect herbicide injury, laboratory analyses of herbicide levels in plant tissue are necessary to confirm the presence of herbicides, although symptoms may be helpful in diagnosing which herbicides caused the problem.

Both damaged and healthy plant tissues should be analyzed, because comparison levels are not readily available for many herbicides. Contact your lab for instructions on which plant parts should be sampled, how to handle and ship the sample, and what costs are involved to ensure an accurate and timely diagnosis.

Triazine injruy to peach leaf
Click to enlarge.