EPPO PP 1/207(2): Efficacy evaluation of plant protection products, Effects on succeeding crops


Plant protection products may have a negative effect on succeeding crops sown or planted in the next growing cycle. The seedling emergence and seedling growth test (OECD 208) can be used to show if the active substance or metabolites of a plant protection product have a potential effect on seedling emergence and early growth of seedlings of succeeding crops.

Study Design

Plant species

The plant species selected for the test should derive from different plant families to consider the taxonomic diversity and should give reliable and reproducible results.

Six plant species are chosen representing typical succeeding crops of a crop in which the plant protection product is intended to be used. Among them could be for example Triticum aestivum (wheat), Zea mays (corn), Brassica napus (oilseed rape), Cucumis sativus (cucumber), Glycine max (soybean) or Helianthus annuus (sunflower).

Test concentrations

Test concentrations are usually determined in a range-finding pre-test and can be calculated based on the expected PEC (Predicted Environmental Concentration) of the test item in the soil.

Course of the test

The test item is incorporated into the soil and seeds are planted in this treated soil. The test item concentration has to be confirmed analytically. After the application the plants are evaluated weekly for effects (emergence and phytotoxticity) in comparison to the water treated control plants for 14 to 21 days after 50 % emergence of the seedlings in the control group. At the test end the endpoints are measured and recorded.

Growth Conditions

The studies are performed in a growth chamber with controlled, optimized test conditions for standardised studies. The temperature is 22 °C during the light period and 18 °C during the dark period (mean 22 °C ± 10 °C) and humidity is 70% ± 25%. During the photoperiod of 16 hours light the intensity is 350 ± 50 µE/m2/s.
For special needs, more differentiated studies and research these conditions can be adapted within a wide range.


Endpoints are emergence, mortality and shootfresh weight. If the test is conducted as multiple rate test effects on fresh weight are reported as ERX (Effective Rate) for each species individually as NOER (No Observed Effect Rate) in case of a limit test.
Additional parameters that can be assessed are shoot height and shoot dry weight. Effects on these parameters are reported as ERX for each species individually.
Phytotoxicity (e.g. chlorosis, necrosis, deforamtion) and growth stages (BBCH code) are recorded.

Guidelines and Literature

  • OECD Guidelines for Testing of Chemicals No. 208 “Terrestrial Plant Test: Seedling Emergence and Seedling Growth Test”.

  • EPPO PP 1/207(2): Efficacy evaluation of plant protection products, Effects on succeeding crops.