use of granules, and products in disposable ready-to-use

containers).

Tier 1

: If application equipment is used for subsequent

treatments with other plant protection products (e.g. ﬁeld

sprayers) the phytotoxic properties of the plant protection

product should be assessed using single-dose phytotoxicity

screening data for crop plants. Testing should be at the

maximum application rate on a range of representative spe-

cies. Selection of species should be based on preliminary

glasshouse tests, knowledge of the mode of action of the

product and the potential crops that may be subsequently

treated with that equipment. This data can usually be taken

from non-target plant testing, as this testing nearly always

includes crop plants, as well as from other greenhouse or

laboratory tests, or from efﬁcacy studies for fungicides and

insecticides if a range of sensitive crops have been tested.

Appendix 2 gives guidance on how to conduct such plant

tests. If the plant protection product causes no symptoms of

phytotoxicity on the plant species tested, no further testing

is necessary.

Tier 2

: If signiﬁcant (

50%) phytotoxicity is observed,

conduct dose

–

response

relationships for species represent-

ing plant families for which signiﬁcant negative activity has

been found. If there is a clear indication that the activity

via one route of exposure (soil or leaves) is far stronger

than by the other, tests should be limited to that exposure

route. These data can also be taken from the non-target

plant (ecotoxicology) section as well as from other green-

house or laboratory tests. See Appendix 2 for details of

plant testing.

Toxicity values derived in these tests are then compared

with predicted concentrations after spraying to develop the

toxicity:exposure ratio (TER; calculated as the ED

value

divided by the amount of residue remaining in the spray

tank).

This

information

may

obtained,

for

example,

from tests to determine the effectiveness of the cleaning

procedure

under

Annex

IIIA

4.2

under

Regulation

284/20135. The TER is then compared with a trigger value

that is based on expert judgement or derived empirically.

If the TER value of the most sensitive crop is

1 (or the

speciﬁc national level, if higher), no further testing is nec-

essary.

Progression to the next tier is warranted if the safety

margin is not met, while testing is stopped if the safety

margin is met or exceeded.

There are several methods by which the residue in the

PAE may be determined: by calculation for highly water-

soluble formulations, by the use of small-scale tests (see

Appendix 1

for

example)

the

testing

using

commercial-scale equipment.

Tier 2a

: Calculation of residues left in the PAE.

When a sprayer is emptied, dilute spray solution will be

retained in the sprayer. According to ISO standards,

for

example,

52 L

spray

solution

are

allowed

remain in the parts of a 2000 L sprayer with a 21 m

boom. An example of how this can be used to calculate

residues left in the PAE is included in Appendix 4. For

soluble active substances

it may be possible to calculate

the worst-case concentration for contamination of applica-

tion machinery. This is determined by taking the average

amount of the original spray dilution that will be left after

application. Then calculate the extent of dilution resulting

from the recommended sprayer cleaning regime and subse-

quent reﬁlling of the sprayer before use of the next prod-

uct. The resulting value can then be used in the TER

calculation to demonstrate if a sufﬁcient level of cleaning

has been achieved. It is unlikely, however, that sufﬁcient

information would be available to calculate the effect of

using a cleaning agent if this is recommended during the

cleaning procedure.

However, for most active substances analytical testing

will be required to determine the amount of active sub-

stance remaining in the sprayer after application of the

plant protection product and subsequent re-ﬁlling before the

next application. The amount of active substance remaining

in the PAE will be affected by the cleaning procedure

adopted.

Tier 2b

: Small-scale/large-scale tests

For the initial examination of the effectiveness of the

cleaning procedure small-scale tests in bottles or jars can

provide more consistent results than results from a full-

scale test. An example protocol for small-scale jar tests

is given in Appendix 3. In small-scale tests there is a

greater surface area to volume ratio, increasing the likeli-

hood that spray residues would adhere to the bottle. The

small-scale containers should be made of a similar mate-

rial

that

used

for

farm-scale

application

machinery,

such

high-density

polyethylene

(HDPE).

The

use

small-plot spray equipment is not recommended because

this is commonly made of metal and the spray is often

delivered using CO

pressure, neither of which represent

normal conditions of application. Small sprayers used in

domestic gardens can be suitable as these may be made

of HDPE. Full-scale tests with commercial sprayers may

also

used

according

ISO

Standard

ISO

16119-

2:2013 (Agricultural and forestry

machinery

–

Environ-

mental requirements for sprayers. Part 2: Horizontal boom

sprayers).

Single products or mixtures can be tested, being added to

the bottles at their highest proposed recommended concen-

tration on the label. The bottles can then be washed using

the method recommended on the label and then the ﬁnal

rinsate analysed for residues of the active substance(s) con-

cerned. The solvent to be used in the ﬁnal rinsate should be

considered in light of the chemical properties of the active

substances under test and need not necessarily be water.

Some active substances are not very soluble in water or

water-insoluble deposits can be formed. In these cases the

ﬁnal rinse which is analysed should be an organic solvent,

such

isophorone,

instead

water.

(This

not

EN/ISO 16119-2:2013.

372

Efﬁcacy evaluation of plant protection products

2016 OEPP/EPPO,

Bulletin OEPP/EPPO Bulletin

, 371–378