Chemosphere, Vol. 39, No. 8, pp.1357-1370. 1999
Pergamon
C) 1999 Elsevier Science lad. All rights reserved 0045-6535/99/$ - see front matter
PIh S0045-6535(98)00489-5
SENSITIVITY OF NON-TARGET ARTHROPODS TO PLANT PROTECTION PRODUCTS: COULD TYPHLODROMUS PYRI AND APHIDIUS SPP. BE USED AS INDICATOR SPECIES ?
M. P. Candolfi l, F. Bakker2, V. Cafiez3, M. Miles 4, Ch. Neumann 5, E. Pilling 6, M. Primiani 7, K. Romijn s, R. Schmuck 9, S. Storck-WeyhermOller~°, A. Ufer" and A. Waltersdorfer ~2
Novartis Crop Protection AG, R-1058.3.64, CH-4002 Basel, Switzerland 2 Mitox Consultants, Kruislaan 320, 1098 Amsterdam, The Netherlands American Cyanamid Company, Agricultural Products Research Division, P. O. Box 400, Princeton, NJ 08543-0400, USA a Dow AgroSciences, Letcombe Laboratory, Letcombe Regis, Wantage, Oxfordshire OX12 9JT, UK 5 Novartis Crop Protection AG, CH-4002 Basel, Switzerland 6 Zeneca Agrochemicals, Jealott's Hill Research Station, Bracknell, Berkshire RG42 6ET, UK DuPont Agricultural Products, Experimental Station, Wilmington, Delaware 19880-0402, USA s Rh6ne-Poulenc, Secteur Agro, 355 rue Dostoievski, BP 153, F-06903 Sophia Antipolis, France 9 Bayer AG, Pflanzenschutzzentrum Monheim, Alfred-Nobel-Strasse 50, D-40789 Monheim, Germany t0 Novartis Agro GmbH, Liebigstr. 51-53, D-60323 Frankfurt/Main, Germany " BASF AG, LandwirtschafUiche Versuchsstation, Postfach 120, D-67114 Limburgerhof, Germany ~2 AgrEvo GmbH, Umweltforschung/Oekobiologie, Werk Hoechst, H872, D-65926 Frankfurt, Germany (Received in Germany 31 March 1998; accepted 26 September 1998)
ABSTRACT
Data on the sensitivity of nine non-target arthropod families to 95 plant protection products (PPP), including herbicides, fungicides, insecticides and plant growth regulators, tested using currently established laboratory methods were analyzed. The data presented were supplied by 11 agro-chemical companies and were generated for regulatory purposes. All the studies were performed in compliance with Good Laboratory Practice (GLP) standards. For the analysis of the relative sensitivity to PPP, the measurement endpoints in each arthropod study performed were separated into lethal (mortality) and sub-lethal effects (e.g. oviposition, hatching rate, food consumption). Differences in sensitivity among arthropod species to the same PPP, the relative sensitivity of arthropod species among PPP tested, and the potential use of the more sensitive species as indicator species for regulatory testing purposes are discussed. Pooling the data for all PPP tested provided a ranking of the sensitivity of the arthropod species using the currently available test systems. Typhlodromus pyri and Aphidius spp., showed the greatest sensitivity to PPP (76.8% and 67.4% of the PPP tested eliciting lethal or sub-lethal effects > 30% to T. pyri and Aphidius spp., respectively). All other species tested were of intermediate sensitivity with approximately 10.5% and 1357
1358 55% of the PPP tested eliciting lethal or sub-lethal effects _>30%. Ranking of the arthropod species tested, in order of decreasing sensitivity and based on a combination of both lethal and sub-lethal endpoints, follows: T. pyrL Aphidius spp., Coccinella septempunctata, Orius spp., Pardosa spp., Episyrphus balteatus,
Chrysoperla carnea, P. cupreus and A. bilineata. Of the 95 PPP evaluated, 23.2% elicited an adverse lethal or sub-lethal effect > 30% on T. pyri without affecting Aphidius sp., 13.7% elicited an adverse lethal or sub-lethal effect > 30% on Aphidius spp. without affecting T. pyri. Among all arthropod species and PPP tested, an adverse effect _>30% on a sub-lethal endpoint was observed in 10% to 20% of the studies without an adverse effect on mortality. For E.
balteatus, C. carnea, P. cupreus and A. bilineata, the percentage of PPP eliciting adverse effects on sublethal parameters was always higher than the percentage of PPP showing effects on mortality. With a combination of both lethal and sub-lethal parameters as the assessment endpoints, if a PPP elicited an adverse effect > 30% on any of the arthropod species tested, an adverse effect also was observed in either T. pyri and Aphidius spp. in 95.8% of the cases. Similar results were obtained if fungicides and herbicides were considered separately (96.0% and 94.1%, respectively). These results indicate that the potential of an arthropod species to be adversely affected following exposure to a PPP under worst-case exposure conditions can be effectively predicted by determining the lethal and sub-lethal effects of the PPP on the two sensitive species, T. pyri and Aphidius spp. © 1999 ElsevierScienceLtd. All rightsreserved
KEY-WORDS
Pesticides, beneficial arthropods, side-effects, sensitivity, Typhlodromuspyri, Aphidius rhopalosiphi,
Aphidius colemanL Aphidius matricariae, Orius insidiosus, Orius laevigatus, Coccinella septempunctata, Episyrphus balteatus, Chrysoperla carnea, Poecilus cupreus, Pardosa spp., Aleochara bilineata
INTRODUCTION
Effects of plant protection products (PPP) on non-target arthropods are a dossier requirement for the placement of agricultural chemical products on the European market [1,2]. This applies both to new active ingredients and to the authorization of plant protection products. At least four different non-target arthropod species (and up to six species if toxicity is observed in one of the first four species tested) must be tested under worst-case laboratory conditions [3]. These data or, in case laboratory Tier I studies show toxicity, data of higher tier testing (e.g., semi-field or field trials) will then be used for the hazard classification and risk assessment of plant protection products.
1359 With the experience gained and with the extensive data base generated over the past 6-7 years on the effects of plant protection products on non-target arthropods, it appeared that the sensitivity of species using the currently available test methods to the same and to different PPP varies significantly. The sensitivity of nine non-target arthropod families to 95 pesticides (including herbicides, fungicides, insecticides and plant regulators) was analyzed. The data presented were supplied by 11 agro-chemical companies and were generated for regulatory purposes between 1990 and 1997. The studies were performed in compliance with Good Laboratory Practice (GLP) standards by the mentioned companies and/or by contract laboratories. The objective was to determine whether arthropod species show differences in sensitivity to pesticides and, if so, to rank the arthropod species based on their sensitivity to products classes (i.e., herbicides, fungicides, and insecticides). This could facilitate the identification of sensitive arthropod species to be used as indicator species to provide reliable and accurate data for regulatory risk assessment procedures. The described results reflect effects under worst case laboratory conditions and can not be transferred directly to relevant field conditions. This evaluation was conducted by and represents the consensus of the current Beneficial Arthropod Regulatory Testing (BART) group membership.
MATERIALS AND METHODS
The raw data used to perform this sensitivity analysis were supplied by the following agro-chemical companies (in alphabetical order): AgrEvo, American Cyanamid, BASF, Bayer, Ciba-Geigy, Dow Elanco, Du Pont, Rhrne-Poulenc, Rohm & Haas, Sandoz and Zeneca. The studies were performed either by these companies or by the following contract laboratories (in alphabetical order): Agrochemical Evaluation Unit, Biochem, GAB Biotechnologie/IFU Umweltanalytik, Huntingdon Research Centre, Ibacon, Mitox and Springborn Laboratories (Europe) AG. Data on 95 formulated plant protection products, including 34 herbicides, 50 fungicides, 10 insecticides and 1 plant growth regulator, were analyzed. To maintain the confidentiality of proprietary data submitted by the agro-chemical companies and because several of the PPP tested are not yet registered, it is not possible to provide explicit information on the test products (e.g., name of the active ingredient and formulation type) other than the PPP class. The criteria used to include a plant protection product in the analyses were as follow: a) at least four studies on the effects of the same PPP to non-target arthropods were available, b) two of these studies were performed with Typhlodromus
pyri and Aphidius spp., c) only laboratory studies (worst-case exposure scenario) performed in GLP compliance were considered and d) the studies were performed according to standardised guidelines.
1360 A non-target arthropod family was included into the data set when at least 15 studies with the same species but with different agro-chemicals were performed. Data on 12 non-target arthropod families were supplied with only nine taxonomic families representing seven taxonomic orders meeting the above criteria for inclusion in the sensitivity assessment. The list of arthropod species considered and the number of tests performed with each species are presented in Table 1.
Table 1.
Non-target arthropod species and number of plant protection products (PPP) tested with the respective species evaluated for the sensitivity analyses.
Arthropod Order
Arthropod Family
Arthropod Species
Number of PPP tested
Acari
Phytoseiidae
Typhlodromus pyri
95
Araneae
Lycosidae
Pardosa spp.'
18
Coleoptera
Carabidae
Poecilus cupreus
75
Coccinellidae
Coccinella septempunctata
29
Staphylinidae
Aleochara bilineata
19
Diptera
Syrphidae
Episyrphus balteatus
15
Heteroptera
Anthocoridae
Orius insidiosus and Orius laevigatus
20 b
Hymenoptera
Aphidiidae
Aphidius rhopalosiphi, Aphidius colemani and Aphidius matricariae
95 c
Neuroptera
Chrysopidae
Chrysoperla carnea
28
' Since the tests with Pardosa are performed with field collected spiders, the spiders used in each of the tests were from different species (e.g., P. amentata, P. palustris, P. agrestis, P. prativaga). Therefore, the results are reported without specific reference to the species. b From 20 Orius studies, 18 were performed with O. insidiosus and 2 with O. laevigatus. The data on these two species were pooled for the sensitivity analyses and reported in the results section as Orius spp.. From 95 Aphidius studies, 89 studies were performed with A. rhopalosiphi, 4 with A. colemani and 2 with A. matricariae. The data on these three species were pooled for the sensitivity analyses and reported in the results section as Aphidiua spp..
1361 Table 2 presents the guidelines used for each of the test species. Most of the methods used were published by the International Organisation for Bio!ogieal Control (IOBC) or by the Biologische Bundesanstalt ftir Land- und Forstwirtschaft, Bundesrepublik Deutseb_land (BBA). The remaining methods, although not published under umbrella organisations such as the IOBC or the BBA, are proposed standard test guidelines by the registration authorities of the European Union and are currently being ring-tested under a joint initiative of the IOBC, European and Mediterranean Plant Protection Organisation (EPPO), BART and COMmercial Ecotoxicological Testing (COMET). An overview of the exposure scenarios, of the life-cycle stage exposed and the endpoints (lethal and sublethal) measured for each of the test species is presented in Table 2, along with the list of references for the test methods. All the studies included at least three treatments: control, test substance (applied at the maximum field application rate or twice the maximum field rate in the case of PPP targeted for multiple applications per season) and toxic standard. The endpoints considered for the sensitivity analyses were mortality (measured during the exposure phase of the test) and the appropriate sub-lethal effect for the test species. In order to perform the sensitivity analyses, the data supplied was standardized to allow comparison among PPP, test methods, and test endpoints. Therefore, PPP mortality values were corrected for the mortality in the control, according to Abbott [4]. Sub-lethal effects such as feeding rate, oviposition, hatching rate and parasitization rate were expressed as percent reduction when compared to the control. Data on lethal (mortality) and sub-lethal effects were divided into two classes, i.e., those with effects greater than or equal to 30% (> 30%) and those with effects less than 30% (< 30%). The threshold value of 30% is currently used in risk assessment by the European Union I51. If several sub-lethal endpoints were assessed (e.g., Aleochara bilineata method of Samsoe-Petersen, Table 2), the most sensitive endpoint was used in the
assessment. In order to evaluate the sensitivity of the arthropods to agro-chemicals, the percent of studies showing adverse effects > 30% was calculated for each arthropod species tested. Thereafter, arthropod species were ranked according to the percentage of PPP eliciting effects >_30%. This was done for fungicides, herbicides and insecticides separately and then for all products combined. To determine whether a limited number of non-target arthropod species can be used as indicator species for regulatory purposes, the two most sensitive species (as identified in the sensitivity analyses) were contrasted to the others. Evaluated was the proportion of PPP which had lethal and/or sub-lethal effects > 30% on the non-target arthropods tested other than the two most sensitive species.
Dry residue
BBA, Rieckmann [14]
Schmuck et al. [7] c
BBA, Wehling and Heimbach [ 15] IOBC, Heimbach [ 16]
Episyrphus balteatus
Orius insidiosus and O. laevigatus
Pardosa spp.
c d
b
a
Direct spray treatment Direct spray treatment Dry residue Glass
Quartz Sand
Quartz Sand
Glass
Glass
Glass
Glass
14 clays
14 days 14 days
Proto-nymph
14 days
app. 21 days
app. 49 days
app. 49-63 days
14-21 days
Larvae
Larvae
Larvae
Sub-adults or adults Adults
app. 56-70 days
app. 12 days
Until emergence of the adults (app.3..4 weeks) Until emergence of the adults (app.21-28days) Until emergence of the adults (app. 28 days) Until the larvac reached the imago stage (app.8-10 days) 14-21 days
species
2 days (A rhopalosiphi) and I day other two
Adults
Larvae
5 days
Adults
Quartz Sand
Glass
Exposure time to the agrochemical 56 days
ExpoSure substrate Quartz Sand
Total duration of the test app. 112 days app. 15 days
yes
Not applicable
Not applicable
no
no
no
no
no
yes
Exposure of arthropods to the pesticide during the reproduction assessments yes
Sub-adult or adult mortality and feeding rate Adult mortality and feeding rate Pre-imaginal mortality and oviposition
Pre-imaginal mortality and oviposition
Pre-imaginal mortality, oviposition and hatching rate Pl-e-imaginal mortality, oviposition and hatching rate Larval mortality and oviposition
Adult mortality, feeding rate, oviposition and hatching rate Adult mortality and parasitization rate
Endpoints considered for the sensitivity analyses Parasitization rate
Data frem studies performed with either ofthe methods werepooled andused for the sensitivity analyses. From the 19 Aleochara studies available (Tab. I), 5 were conducted according to the method of Samsoe-Petersen [9] and 14 according to the method of Moreth and Naton [8]. Data from studies performed with either of the methods were pooled and used for the sensitivity analyses. The studies performed with A. rhopalosiphi(Tah I) were conducted according to the method of Mead-Briggs [11] while the studies with A. colemani and A. matricariae were performed according to Polgar [10]. In principle the two methods are similar (same test units and study endpoints). The main difference is the exposure time of the adult insects (24 hours in the Polgar method and 48 hours in the Mead-Briggs method) in the treated test units. Modification of an IOBC method, originally published to test predatory mites (Coffin Cell method [ 18]). Data from studies performed with either of the three methods were pooled and used for the sensitivity analyses. From 95 studies performed (Tab. I ), 70 were performed according to the method of Overmeer [ 17], 9 according to Bakker et al. [ 18] and 16 according to Louis and U fer [ 19].
Typhlodromus pyri d
IOBC and other, Overmeer [17], Bakker et al. [18], or Louis and Ufer [19]
Dry residue
BBA, Pinsdorf [13]
Coccinella septempunctata
Poecilus capreus
Dry residue
IOBC, Bigler [ 12]
Chrysoperla cornea
Dry residue
Dry residue
IOBC and other, Polgar [10] or Mead-Briggs [I 1]
Aphidius rhopalosiphi, A. colemani and A. matricariae b
Exposure type Direct spray treatment Direct spray treatment
Guideline/Method IOBC, Moreth and Naton [8] IOBC, Samsoe-Petersen [9]
Arthropod stage exposed to the agrochemical at test initiation Adults
Overview of the guidelines, exposure scenarios and the endpoints measured in tests conducted with non-target arthropods.
Arthropod species dleochara bilineata a
Table 2.
Lo to
1363 RESULTS
Analysis of the relative sensitivity among tested arthropod species When ranking the relative sensitivity of the non-target arthropods tested to the PPP tested (i.e., fungicides, herbicides, insecticides and plant growth regulators pooled data), T. pyri and Aphidius spp., were the most sensitive (76.8% and 67.4% of the products showed lethal and/or sub-lethal effects > 30%, respectively). P. cupreus and ,4. bilineata were the least sensitive species (16.0% and 10.5% of the products showed lethal and/or sub-lethal effects > 30%, respectively). All other test species were of intermediate sensitivity (approximately 30% and 55% of the products showed adverse effects). Ranking of the arthropod species tested, in order of decreasing sensitivity and based on a combination of both lethal and sub-lethal endpoints, follows: T. pyri, Aphidius spp., Coccinella septempunctata,
Orius spp., Pardosa spp.,
Episyrphus balteatus, Chrysoperla carnea, P. cupreus and A. bilineata (Table 3). If only the mortality endpoint is examined in the assessment, the only change in the sensitivity of the species position is a shift between C. septempunctata and Orius spp., with T. pyri and Aphidius spp. remaining the most sensitive species. If only sub-lethal effects endpoints are considered in the assessment, the species sensitivity ranking changes slightly, however, T. pyri and Aphidius spp. remained as the most sensitive species. The sensitivity ranking established by pooling all of the PPP tested was similar to the ranking for fungicides and herbicides (Table 4). T. pyri and Aphidius spp., were the most sensitive whereas P. cupreus and A. bilineata were the least sensitive species. None of the herbicides tested resulted in an adverse effect on E. balteatus or `4. bilineata. A ranking of the sensitivity of the test arthropods to insecticides could not be established. All the insecticides tested caused effects _>30% in all of the species tested except for T. and P. cupreus pyri where respectively, 90% and 66.7% of the insecticides caused effects > 30% (Table 4). The lack of an effect on the predatory mite T. pyri in 1 of the 10 insecticides tested may have been due to the specific mode of action of test compound and its lack of acaricidal properties. When insecticides are excluded from the sensitivity analysis, the ranking of the species changes only slightly (Figure 1) when compared to the results obtained by including the insecticides (Table 3). The only position switch is between C carnea and E. balteatus. However, both species showed to have a similar sensitivity to plant protection products (33.3% and 32.1% of the products showed lethal and/or sub-lethal effects on E. balteatus and C carnea, respectively when all products were pooled, and 23.1% and 26.9%, respectively when the insecticides were excluded).
1364
Overall response of non-target arthropods to plant protection products (studies performed with fungicides, herbicides, insecticides and plant growth regulators were pooled). Reported in the table are the percentage of plant protection products (PPP) showing lethal and/or sub-lethal effect (> 30%). The non-target arthropod species are listed in decreasing order of sensitivity.
Table 3.
Percent PPP showing lethal and/or sub lethal effects ~ 30% 76.8 (95)'
Percent PPP showing effects on mortality _>30% 60.0 (95)
Percent PPP showing sub-lethal effects >_30% 56.3 (71 )
Aphidius spp.
67.4 (95)
50.5 (95)
47.8 (69)
Coccinella septempunctata
55.2 (29)
34.5 (29)
29.2 (24) 35.3 (17)
Arthropod species Typhlodromus pyri
Orius spp.
50.0 (20)
40.0 (20)
Pardosa spp.
38.9 (18)
27.8 (18)
11.8 (17)
Episyrphus balteatus
33.3 (l 5)
13.3 (15)
28.6 (14)
Chrysoperla carnea
32. l (28)
10.7 (28)
26.9 (26)
Poecilus cupreus
16.0 (75)
8.0 (75)
Aleochara bilineata
10.5 (19)
7.7 (13)
12.9 (70) 10.5 (19)
'
The number in parentheses represents the number of studies (sample size) used in the calculations.
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(5 Arthropod species Figure 1.
Response of non-target arthropods to fungicides, herbicides and pant growth regulators (data pooled). Reported in the figure is the percentage of plant protection products showing lethal and/or sub-lethal effects (_>30%) on arthropods.
1365 Table 4.
Response of non-target arthropods to fungicides, herbicides and insecticides. Reported in the table are the percentage o f plant protection products (PPP) showing lethal and/or sub-lethal effect (-> 30%). For all the product classes the non-target arthropod species are listed in decreasing order of sensitivity.
PPP CLASS
Arthropod species
Percent PPP showing lethal and/or sub lethal effects > 30%
Percent PPP showing effects on mortality > 30%
Percent PPP showing sublethal effects >- 30%
FUNGICIDES Typhlodromus pyri Aphidius spp. Coccinellaseptempunctata Orius spp. Episyrphus balteatus Chrysoperla carnea Poecilus cupreus Aleochara bilineata
78.0 (50)" 60.0 (50) 47.4 (19) 45.5 (11) 33.3 (9) 25.0 (16) 10.3 (39) 0 (8)
58.0 (50) 48.0 (50) 21.1 (19) 27.3 (11) 0 (9) 6.3 (16) 0 (39) 0 (6)
62.5 (40) 47.6 (42) 31.6 (19) 33.3 (9) 33.3 (9) 26.7 (15) 10.3 (37) 0 (8)
HERBICIDES Typhlodromus pyri Aphidius spp. Orius spp. Coccinella septempunctata Chrysoperla carnea Pardosa spp. Poecilus cupreus Episyrphus balteatus Aleochara bilineata
70.6 (34) 67.7 (34) 50.0 (6) 40.0 (5) 30.0 (10) 28.6 (14) 7.4 (27) 0 (4) 0 (9)
52.9 (34) 38.2 (34) 50.0 (6) 20.0 (5) 0 (10) 21.4 (14) 0 (27) 0 (4) 0 (5)
46.4 (25) 48.0 (28) 40.0 (5) 20.0 (5) 30.0 (10) 7.1 (14) 7.4 (27) 0 (4) 0 (9)
INSECTICIDES Aphidius spp. A leochara bilineata Chrysoperla carnea Coccinella septempunctata Episyrphus balteatus Orius spp. Pardosa spp. Typhlodromuspyri Poecilus cupreus
100.0 (10) 100.0 (2) 100.0 (2) 100.0 (5) 100.0 (2) 100.0 (2) 100.0 (2) 90.0 (10) 66.7 (9)
100,0 (10) 100.0 (2) 100.0 (2) 100.0 (5) 100.0 (2) 100.0 (2) 100.0 (2) 90.0 (10) 66.7 (9)
50.0 (2) _b
' b
The number in parentheses represents the number of studies (sample size) used in the calculations. NO data available since 100% mortality was observed during the exposure phase of the study.
50.0 (2) 50.0 (6)
1366
Extrapolation of effects to non-target arthropods using data generatedfor the two most sensitive species As mentioned above, the two species which showed the highest sensitivity to agro-chemicals were the predatory mite, T. pyri, and the parasitic wasp, Aphidius species. Of the 95 PPP evaluated (pooled data), 23.2% elicited an adverse lethal and/or sub-lethal effect __-30% on T. pyri without affecting Aphidius spp., 13.7% elicited an adverse lethal and/or sub-lethal effect > 30% on Aphidius spp. without affecting T. pyri. The effects on these two species were compared separately and in combination to the other test species, because of their high sensitivity and consistent response to a wide range of PPP. The comparisons were conducted to determine the feasibility of using T. pyri and Aphidius spp. as indicator species to reliably predict the potential o f a PPP to adversely affect arthropod species. With a combination of both lethal and sub-lethal endpoints, i f a PPP elicited an adverse effect on any of the arthropod species tested, an adverse effect also was observed in either T. pyri and Aphidius spp. in 95.8% of the PPP tested (pooled data of fungicides, herbicides, insecticides and plant growth regulators) (Table 5). The 4.2% of the PPP tested which did not result in adverse effects > 30% on T. pyri and Aphidius spp. represented 4 of 95 PPP tested.
Two herbicides resulted in sub-lethal effects on C. carnea (without
affecting mortality) and two fungicides resulted in lethal effects on O. insidiosus and one of these also resulted in lethal effects on C. septempunctata. Assessment of T. pyri and Aphidius spp. data separately indicated that if a PPP elicited a lethal and/or sublethal adverse effect on any of the arthropod species tested, 82. 1% and 72.6% of the PPP would produce an adverse effect on T. pyri and Aphidius spp., respectively. When using mortality as the only endpoint, if a PPP elicited an adverse effect on any of the arthropod species tested, an adverse effect also was observed in either T. pyri and Aphidius spp. in 93.7% of the t;PP tested (pooled data). The use of sub-lethal endpoints alone was less effective in identifying potential adverse effects, with 86.3% of the PPP resulting in an affect on either T. pyri or Aphidius spp., as well as any other arthropod species.
1367 Table 5.
Evaluation of the possibility to extrapolate under worst-case laboratory conditions the sideeffects of the agro-chemicals to non-target arthropods using Typhiodromuspyri and Aphidius spp. as indicator species. Presented in the table is the percentage of plant protection products (PPP) not eliciting an adverse effect (>_ 30%) to other species tested than two most sensitive species.
Arthropod species selected to extrapolate the sideeffects on all other species tested •
Type of agro-chemical
Percent of PPP showing no sideeffects to other species tested than to the one's mentioned in the first column of the table
T. pyri and Aphidius spp.
All PPP pooled
95.8 (93.7 / 86.3) b
(pooled) Fungicides Herbicides Insecticides
96.0 (94.0 / 88.0) 94.1 (91.2 / 91.2) 100.0 (0 / 0)
T. pyri
All PPP pooled Fungicide Herbicide Insecticide
82.1 84.0 76.5 90.0
Aphidius spp.
All PPP pooled Fungicide Herbicide Insecticide
72.6 66.0 73.5 100.0
The complete list of non-target arthropod species tested is presented in Table 1. The values in front of the parentheses were calculated considering both lethal and/or sublethal endpoints, while the values in parenthesis were calculated based on lethal or sub-lethal endpoints, respectively.
DISCUSSION
The test systems used in the initial phase of laboratory testing, which utilize an artificial substrate and exposure the test species to the maximum labelled application rate of the PPP, are designed to represent a worst-case exposure scenario. This is demonstrated by this evaluation which shows that 76.8% of the PPP caused adverse effects _>30% on at least one of the tested species. The results demonstrate also that nontarget a ~ r o p o d species, representative of nine taxonomic families and seven taxonomic orders, vary in their sensitivity to plant protection products. The different sensitivity is due to a combination of the intrinsic sensitivity of the tested species to a wide range of PPP and the severity of the test systems. The species sensitivity ranking established in this evaluation (in decreasing order sensitivity T. pyri, Aphidius
1368 spp., Coccinella septempunctata, Orius spp., Pardosa spp., Episyrphus balteatus, Chrysoperla carnea. P. cupreus and A. bilineata) is also reflected in the data presented by Forster [6], but this author restricted his conclusions to within functional group comparison. Therefore, a direct comparison of the two evaluations should be made with care. Moreover, the data used by Forster [6] include in addition to the laboratory studies also semi-field and field results and not all the species evaluated in our study were also evaluated in the other study. However, it appears evident that in both evaluations, T. pyri (Aphidius spp. were not reported in the evaluation of Forster), was the most and P. cupreus and A. bilineata were the least sensitive species. Coccinella septempunctata and Chrysoperla carnea were of intermediate sensitivity in both studies.
The percentage of PPP showing an adverse effect (> 30%) on mortality was considerably lower than the percentage of studies showing adverse effects on mortality and sub-lethal parameters combined. For E. balteatus, C. carnea, P. cupreus and A. bilineata, the percentage of products eliciting sub-lethal adverse effects was always higher than the percentage of products eliciting effects on mortality alone. Whether this addition of percentage reflects false positive effects or whether they represent true effects remains to be established through comparison with higher tier data. In this context it is relevant to refer to Schmuck et al. [7]. These authors pointed out that the reproductive performance of some non-target arthropod species (e.g. Coccinella septempunctata, Chrysoperla carnea and Aphidius rhopalosiphi), tested using the current available guidelines, is subjected to high inherent variability. According to the authors, this could lead with a mean probability of 25-35% to label a PPP either as a false positive or false negative.
An assessment of both lethal and sub-lethal endpoints showed that if a PPP elicited an adverse effect on any of the arthropod species tested, the percentage of PPP eliciting an adverse effect in either T. pyri and Aphidius spp., was 95.8% if both endpoints were considered. If mortality was considered as the only endpoint, the predictive power (for mortality only) was 93.7% and 86.3% if only sub-lethal endpoints were considered.
The use of indicator species to assess the potential toxicity of PPP is commonly used in
generating risk assessment data for the areas of aquatic (e.g., Daphnia, Chironomus, rainbow trout), avian (e.g., Mallard Duck, Japanese or Bobwhite Quail), and terrestrial (e.g., earthworm) ecotoxicology [1, 2]. The use of indicator species is an established testing strategy to allow the potential impact of a PPP on the species residing in habitats of concern (e.g., aquatic species in ponds, avian species in riparian areas) to be assessed. Due to the wide range of habitats which may be exposed to a PPP, the testing of specific species residing in particular habitats of concern is impracticable and often impossible.
Therefore, the use of
indicator species is a widely recognised and accepted method of risk assessment. An indicator species
1369 should be readily available and easily cultured for laboratory test conditions. The indicator species should be sensitive to a wide variety of toxicants, not an endangered species, indicative of the environment of concern (i.e., potential exposure to plant protection products). The test using the indicator species should be standardised, simple, reproducible, and of short duration.
Assessment of the data did not identify a
single arthropod species which would meet the above criteria for use as an indicator species but the criteria are met if T. pyri and Aphidius spp. are used in combination as indicator species. The data indicate that the criterion for sensitivity to a wide variety of toxicants is met when both species are tested and when both lethal and sub-lethal effects are considered. The elimination of one of the species or either the lethal or sub-lethal endpoints reduces the potential to use the toxicity of a PPP on T. pyri and Aphidius spp. to predict adverse effects on arthropods species found in cropping systems and off-field habitats.
The results indicate that the potential of an arthropod species to be adversely affected following exposure to a PPP can be effectively predicted by determining the toxicity of the PPP on T. pyri and Aphidius spp., the two most sensitive species.
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