Garden Chafer | Phyllopertha horticola (L.)

California Pest Rating  for
Garden Chafer | Phyllopertha horticola (L.)
Coleoptera: Scarabaeidae: Rutelinae
Pest Rating: A



Initiating Event:

Phyllopertha horticola is currently Q-rated.  A permanent pest rating proposal is required to support an official pest rating.

History & Status:

Background:  Adult Phyllopertha horticola measure 8.5 to 12 mm in length and have red-brown elytra, a metallic blue or green pronotum, and a hairy lower (ventral) surface (Agricultural Research Service, 1957).  They have a one-year life cycle (Hann et al., 2015).  Both adults and larvae feed on living plant tissue and cause economic damage (Ruther and Mayer, 2005).  The adults feed on leaves of many different plants, including fruit trees, and they also feed on fruit, including apples, and flowers (Agricultural Research Service, 1957; Hill, 1987). They have been shown to be attracted strongly to plant volatiles, which could explain why this beetle tends to occur in dense aggregations near damaged (chewed) plant tissue (Jackson, 2006; Ruther and Mayer, 2005). The larvae live underground and feed on roots, including those of apple and grasses (Agricultural Research Service, 1957).  They are reported to be the most important white grub damaging agricultural grassland in the Austrian alps (Hann et al., 2015), and they were also reported to be a significant pest in turf grass in the United Kingdom (Mabbett, 2009).  This beetle is reported to be a pest of strawberry and sea buckthorn in Latvia, although the life stage responsible for damage was not reported (Petrova et al., 2013; Stalažs, 2015).  Damage in Europe has been estimated to be on the order of hundreds of millions of Euros each year, and the damage is apparently increasing (Pernfuss et al., 2005). When this beetle is abundant, predators, including birds and mammals, are attracted and this can create problems.  For example: Gulls attracted to flying adult P. horticola created an aviation hazard in Norway, and birds feeding on the larvae of this beetle damage turfgrass (Aas et al., 2008; Mabbett, 2009).

Worldwide Distribution:  Phyllopertha horticola is found in Europe (including Austria, Latvia, Norway, and the United Kingdom), Russia, and Tibet (Aas et al., 2008; Agricultural Research Service, 1957; Hann et al., 2015; Petrova et al., 2013; Stalažs, 2015).

Official Control: Phyllopertha horticola is not known to be under official control anywhere.

California Distribution:  Phyllopertha horticola is not known to occur in California.

California Interceptions:  Phyllopertha horticola has been intercepted in an unidentified shipment and in the cargo area of a plane, both from Tennessee, in 2010 and 2011 (CDFA Pest and Damage Report Database, 2018).

The risk Phyllopertha horticola would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Phyllopertha horticola is distributed across a wide area, and it is likely that the climate present in much of California would suit this species. This beetle feeds on a wide variety of plants, and it would probably find suitable host plants in much of California.  This species is likely capable of establishing a widespread distribution in the state. Therefore, Phyllopertha horticola receives a High (3) in this category.

– Low (1) Not likely to establish in California; or likely to establish in very limited areas.

– Medium (2) may be able to establish in a larger but limited part of California.

– High (3) likely to establish a widespread distribution in California.

2) Known Pest Host Range: Phyllopertha horticola adults and larvae feed on living plant tissue, but they differ in that the larvae live underground and feed on roots of grasses and possibly (anecdotal information) other plants as well. The adults feed on leaves, fruit, and flowers of plants in at least two families, the Rosaceae and the Elaeagnaceae.  Therefore, it receives a Medium (2) in this category.

– Low (1) has a very limited host range.

– Medium (2) has a moderate host range.

– High (3) has a wide host range.

3) Pest Dispersal Potential: Adult Phyllopertha horticola   It is possible that larvae could be dispersed via movement of infested, potted plants, although evidence of such dispersal has not been found.  Therefore, it receives a Medium (2) in this category.

– Low (1) does not have high reproductive or dispersal potential.

– Medium (2) has either high reproductive or dispersal potential.

– High (3) has both high reproduction and dispersal potential.

4) Economic Impact: Phyllopertha horticola is a recognized pest, both in the larval as well as in the adult stage.  If this beetle became established in California, it could become a pest in agricultural situations, for example, in orchards, tree nurseries, or pastures. Therefore, it receives a Medium (2) in this category.

Economic Impact:  A, B

A. The pest could lower crop yield.

B. The pest could lower crop value (includes increasing crop production costs).

C. The pest could trigger the loss of markets (includes quarantines).

D. The pest could negatively change normal cultural practices.

E. The pest can vector, or is vectored, by another pestiferous organism.

F. The organism is injurious or poisonous to agriculturally important animals.

G. The organism can interfere with the delivery or supply of water for agricultural uses.

Economic Impact Score:  2

– Low (1) causes 0 or 1 of these impacts.

– Medium (2) causes 2 of these impacts.

– High (3) causes 3 or more of these impacts.

5) Environmental Impact: If Phyllopertha horticola became established in California, it could invade a variety of ecosystems, including prairie and grassland, where feeding by the larvae could disrupt native plant communities. This beetle could become a pest of trees and lawns in California, which could lead to treatment programs.  Therefore, it receives a High (3) in this category.

Evaluate the environmental impact of the pest on California using the criteria below.

Environmental Impact:  A, D, E

A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.

 B. The pest could directly affect threatened or endangered species.

C. The pest could impact threatened or endangered species by disrupting critical habitats.

D. The pest could trigger additional official or private treatment programs.

E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.

 Score the pest for Environmental Impact. Score:

Environmental Impact Score:  3

– Low (1) causes none of the above to occur.

– Medium (2) causes one of the above to occur.

– High (3) causes two or more of the above to occur.

Consequences of Introduction to California for Phyllopertha horticola: Medium (12)

Add up the total score and include it here.

–Low = 5-8 points

–Medium = 9-12 points

–High = 13-15 points

6) Post Entry Distribution and Survey Information: Phyllopertha horticola is not known to be present in California.  It receives a Not established (0) in this category.

–Not established (0) Pest never detected in California, or known only from incursions.

–Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).

–Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.

–High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.

Final Score:

7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (12)


There appears to be little uncertainty regarding the potential of Phyllopertha horticola to become an established pest in California.  The climate appears to be suitable, host plants are presumably widespread in the state, and this beetle is already a recognized pest in Europe.

Conclusion and Rating Justification:

Phyllopertha horticola is a serious pest of fruit trees, grass, and other plants in its native Europe, and it poses the same threat to California, where it is not yet known to occur.  For these reasons, an “A” rating is justified.


Aas, C. K., Olstad, T., Drageset, O.- M., Haukeland, S., Kleppestø, O., and Rukke, B. A.  2008.  A biological battle against the thousands of garden chafers (Phyllopertha horticola) that attract large numbers of gulls (Larus sp.) during the summer season at Rygge Air Station, Norway.  International Bird Strike Committee.  Accessed February 2, 2018:

Agricultural Research Service.  1957.  Insects not known to occur in the United States.  Cooperative Economic Insect Report 7:1-67.

CDFA Pest and Damage Report Database.  2018.  Phyllopertha horticola.  Plant Health and Pest Prevention Services. CA Department of Food and Agriculture.  Accessed February 2, 2018:

Hann, P., Trska, C., Wechselberger, K. F., Eitzinger, J., and Kromp, B.  2015.  Phyllopertha horticola (Coleoptera: Scarabaeidae) larvae in eastern Austrian mountainous grasslands and the associated damage risk related to soil, topography and management.  SpringerPlus 4:139: 1-15.

Hill, D. S.  1987.  Agricultural Insect Pests of Temperate Regions and Their Control.  Cambridge University Press, New York, NY

Jackson, T. A.  2006.  Scarabs as pests: A continuing problem.  Coleopterists Society Monograph 5:102-119.

Mabbett, T.  2009.  Chafer grub, the pre-eminent insect pest of UK turf.  Greenkeeper International, May, 2009: 21-23.

Pernfuss, B., Zelger, R., Kron-Morelli, R., and Strasser, H.  2005.  Control of the garden chafer Phyllopertha horticola with GranMet-P, a new product made of Metarhizium anisopliae.  Insect Pathogens and Insect Parasitic Nematodes: Melolontha.  International Organization for Biological and Integrated Control of Noxious Animals and Plants, West Palearctic Regional Section Bulletin 28:9-12.

Petrova, V., Jankevica, L., and Samsone, I.  2013.  Species of phytophagous insects associated with strawberries in Latvia.  Proceedings of the Latvian Academy of Sciences, Section B, 67:124-129.

Ruther, J. and Mayer, C. J.  2005.  Response of garden chafer, Phyllopertha horticola, to plant volatiles: from screening to application.  Entomologia Experimentalis et Applicata 115:51–59.

Stalažs, A.  2015.  Review of sea buckthorn pests in Latvia.  p. 88 in Sanna, K. and Ekaterina, P. (eds.), Producing Sea Buckthorn of High Quality, Proceedings of the 3rd European Workshop on Sea Buckthorn.  Natural Resources Institute Finland, Helsinki, Finland.

Symbiota Collections of Arthropods Network.  Accessed February 2, 2018:



Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741;[@]

Responsible Party:

Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211,[@]

Comment Period:* CLOSED

7/3/18 – 8/17/18


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Pest Rating: A


Posted by ls