Herbicide phytotoxicity

Kind of organism : Disorders and damages

Detection method : Visual

All diseases & pests

Possible causes

Potato crops can suffer herbicide injuries from different causes:

Seed tubers

The seed potato plants may have been accidentally contaminated during the previous year’s treatment with hormones or other herbicides (clopyralid, glyphosate, etc.) or with a sprouting inhibitor applied to the growing crops (maleic hydrazide). Another possibility is an accidental contamination of seed tubers in storage by a sprouting inhibitor (chlorpropham (CIPC)).


The soil may contain residues of the herbicide used on the previous crop, e.g. a hormone (clopyralid) overdose causing post-emergence plant deformation. This phenomenon can be observed either over the entire field or in patches (e.g. in the case of spray overlapping).

Similarly, an accumulation of these products in crop residues or in organic soil amendments (manure) may cause the same phenomenon.



The extend of the damage is not necessarily related to the spectacular appearance of the symptoms. The consequences for the yield of herbicide phytotoxicity are better assessed by the time and duration of the symptoms rather than by their intensity.

Symptoms induced by a potato herbicide

Symptoms due to the non-selectivity of some herbicides can vary greatly and may be observed at different crop stages, usually on the foliage.

Appearance of these symptoms depends on the mode of action of the active ingredient. Several types of symptoms due to herbicides may be distinguished:

Symptoms induced by non-selective herbicides

The accidental application of non-selective potato herbicides may cause severe damage to potato crops:

Localisation of the symptoms

The symptoms of herbicide phytotoxicity appear in different ways and may point to the source of the problem:


As chemical dosages per hectare have been very significantly reduced in recent years, herbicide persistence is becoming increasingly rare.


To minimise the risk of accidents, the following measures are recommended for the use of herbicides:

Furthermore, it is highly advisable to use certified seed potatoes and, in the case of rented land, to check which pesticide treatments were applied to the previous crops.