Mealybug | Palmicultor browni | Pest Rating Proposals and Final Ratings

California Pest Rating for

Mealybug | Palmicultor browni (Williams)

Hemiptera: Pseudococcidae

Pest Rating: A

PEST RATING PROFILE

Initiating Event:

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

History & Status:

Background: This mealybug is associated with palms, including Adonidia merrillii, Chrysalidocarpus lutescens, Cocos nucifera (coconut palm), Elaeis guineensis (oil palm), Howeia forsteriana, Phoenix roebelenii, and Veitchia spp. (Arzola, 2014; Evans and Dooley, 2013; García Morales et al. 2016; Mille et al., 2016; Stocks, 2013). Its pest status is uncertain. Several sources state it is not a significant pest, but one suggests that it sometimes causes dieback of infested palms in Florida (Hodges and Hodges; Miller et al., 2002; Stocks, 2013).

Worldwide Distribution: Palmicultor browni is probably native to the Australasian region. It has been introduced to the United States, South America, the Caribbean, and areas in the Pacific outside its native range, including New Caledonia (Evans and Dooley, 2013; Mille et al., 2013). It was found in Florida in 1995, and as of 2013, it was present in five counties in that state (Miller et al., 2002; Stocks, 2013). This species has been intercepted in California on shipments originating in Florida (see below). It has not been reported from anywhere other than Florida in the United States.

Official Control: Palmicultor browni is not known to be under official control anywhere.

California Distribution: Palmicultor browni is not known to be present in California.

California Interceptions: Palmicultor browni has been intercepted on palm plants from Florida (PDR # 1261855) and was found on a palm in a Los Angeles County nursery (PDR # 190P06620038) and on a palm (apparently from Florida) at an Orange County store, (PDR # 300P06609688).

The risk Palmicultor browni would pose to California is evaluated below.

Consequences of Introduction:

1) Climate/Host Interaction: Palmicultor browni is apparently restricted to tropical/subtropical areas. It is only known to feed on palms. It is possible that it could become established in a very limited portion of California, including coastal southern California. Therefore, Palmicultor browni receives a Low (1) 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: Palmicultor browni has been associated with seven genera of palms. 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: Mealybugs can be transported with plants. Adult female mealybugs do not fly, and Palmicultor browni only reproduces sexually (unlike some mealybugs, it is not capable of parthenogenesis). 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: Palmicultor browni is only known to feed on palms. Therefore, the only possible economic impacts in California appear to be date production and ornamental palms. It seems unlikely that this tropical/subtropical species could thrive in the California desert areas where dates are grown. It is more likely that it could be a problem in palm nurseries, especially in coastal southern California. Infestations in nurseries could increase production costs. Therefore, it receives a Low (1) in this category.

Economic Impact: 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: 1

– 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: Palmicultor browni only feeds on palms. There is only one species of palm native to California, Washingtonia filifera. It is unlikely that browni could thrive in the desert environment where this native palm occurs naturally. This mealybug could attack ornamental palm plantings. Therefore, it receives a Medium (2) in this category.

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

Environmental Impact: 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.

Environmental Impact Score: 2

– 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 Palmicultor browni: Low (8)

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: Palmicultor browni is not known to occur 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: Low (8)

Uncertainty:

It is possible that this mealybug could become established in coastal California, but there is little evidence that it is a serious pest anywhere.

Conclusion and Rating Justification:

Palmicultor browni is a palm-feeding species that is not known to occur in the state. Ornamental palms are a $70 million industry in California, and damage (including lowering of yield) to palms in nurseries could result if P. browni becomes established here (Hoddle). For these reasons, an “A” rating is justified.

References:

Arzola, C.G.D. 2014. Revisión anotada sobre la taxonomía de Pseudococcidae

(Hemiptera: Coccoidea) en Puerto Rico. M.S. thesis, Universidad de Puerto Rico, Mayagüez, Puerto Rico.

Evans, G.A. and Dooley, J.W. 2013. 18: Potential invasive species of scale insects for the USA and Caribbean Basin., pp. 320-341. In J. Peña (ed.), Potential Invasive Pests of Agricultural Crops. CABI.

García Morales, M., Denno, B.D., Miller, D.R., Miller, G.L., Ben-Dov, Y., and Hardy, N.B. 2016. ScaleNet: A literature-based model of scale insect biology and systematics. Database. doi: 10.1093/database/bav118. Accessed December 18, 2017. http://scalenet.info

Hoddle, M. Has the South American palm weevil, Rhynchophorus palmarum, established in southern California? University of California, Riverside, Center for Invasive Species Research. Accessed: November 17, 2017 http://cisr.ucr.edu/palmarum.html

Hodges, A. and Hodges, G. Exotic Palmicultor mealybugs in Florida. University of Florida, Institute of Food and Agricultural Services. Accessed October 30, 2017. http://mrec.ifas.ufl.edu/lso/exoticscale&mealybug.htm

Mille, C., Henderson, R.C., Cazères, S., and Jourdan, H. 2016. Checklist of the scale insects (Hemiptera: Sternorrhyncha: Coccomorpha) of New Caledonia. Zoosystema. 38(2): 129-176.

Miller, D.R., Miller, G.L., Hodges, G.S., and Davidson, J.A. 2005. Introduced scale insects (Hemiptera: Coccoidea) of the United States and their impact on U.S. agriculture. Proceedings of the Entomological Society of Washington. 107(1): 123-158.

Miller, D.R., Miller, G.L., and Watson, G.W. 2002. Invasive species of mealybugs (Hemiptera: Pseudococcidae) and their threat to U.S. agriculture. Proceedings of the Entomological Society of Washington. 104(4): 825-836.

Stocks, I. 2013. 18: Potential invasive species of scale insects for the USA and Caribbean Basin., pp. 342-362. In J. Peña (ed.), Potential Invasive Pests of Agricultural Crops. CABI.

Author:

Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741, plant.health[@]cdfa.ca.gov

Responsible Party:

Jason Leathers, 2800 Gateway Oaks, Sacramento CA 95833, (916) 654-1211, plant.health[@]cdfa.ca.gov

Comment Period:* CLOSED

3/15/18 – 4/29/18

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