112 Florida Entomologist 94(1) March 2011

TRACHYAPHTHONA NIGRITA AND TRACHYAPHTHONA SORDIDA (COLEOPTERA: CHRYSOMELIDAE) REJECTED AS POTENTIAL BIOLOGICAL CONTROL AGENTS OF PAEDERIA FOETIDA L. (), AN INVASIVE WEED IN HAWAII AND FLORIDA

ROBERT W. PEMBERTON1 AND GLORIA L. WITKUS Department of Agriculture, Agricultural Research Service, Invasive Research Laboratory, 3225 College Ave., Ft. Lauderdale, FL 33314

[email protected]

Skunk vine, Paederia foetida L. (Rubiaceae), is range testing for T. nigrita and T. sordida initially an invasive weed native to Asia but a problem in concentrated on 3 subfamilies within the Rubi- Florida and other areas of the southern USA, and aceae. Test were native and ornamental in Hawaii (Pemberton & Pratt 2002). In the members of this family selected to represent dif- southern states of the USA it is mostly a problem ferent taxonomic tribes. Host range testing on in natural areas, whereas in Hawaii the plant is a plants outside of the Rubiaceae consisted of spe- problem in both natural areas and agriculture. cies selected to represent related orders including Skunk vine is both a Category I weed (Florida Ex- the Cornales, , Lamiales, and the So- otic Pest Plant Committee 2009) and a Florida lonales. In total, 34 species in 7 families and 5 or- Noxious Weed (USDA, Natural Resource Conser- ders were tested. vation Service). Host range tests on both beetles were con- Biological control research began with field ducted with a no-choice test design, and each in- surveys in Asia in 1997 (Pemberton & Pratt dividual test plant was exposed to 3 beetles for 1 2002). A lace bug, Dulinius conchatus Distant month. Control plants of P. foetida and P. crudda- (Tingidae), and a leaf beetle, Sphenoraia rutilans siana were exposed to 3 beetles for 1 month. Be- Hope (Chrysomelidae) have undergone host spec- cause research on T. nigrita spanned 2 seasons, ificity testing but neither demonstrated the nar- each experiment was replicated 5 times. Research rowness of host range needed in a skunk vine bio- on T. sordida was conducted for 1 season so each control agent (Pemberton et al. 2005; Pemberton test was replicated 3 times. Host range testing for & Witkus unpublished data). Two Trachyaph- T. nigrita and T. sordida was conducted on thona spp. flea beetles were identified as promis- branches of whole potted plants in the quarantine ing biological control candidates during surveys greenhouse. Clear acrylic tubes, 15.2 cm long × in Japan (Pemberton & Pratt 2002). Both species 3.8 cm diameter (6” × 1.5” diameter), each with 2 have larvae that feed on roots and adults that mesh ventilation holes, were placed on the end of consume leaves. The biology and preliminary host a small branch or stem of each test plant. A slit ranges of Trachyaphthona sordida (Baly) and T. sponge bung was placed around the base of the nigrita Ohno were studied in Japan (Okamato et stem and up into the bottom of the tube. The stem al. 2008). and bung juncture was wrapped tightly with Adult host range testing on T. nigrita was con- parafilm. Another bung was used to seal the top of ducted in our Fort Lauderdale quarantine labora- the tube. Due to the saltatory nature of the flea tory during 2007 and 2008, with field-collected beetles, an aspirator was used to gently transfer 3 beetles shipped by Japanese cooperators during tiny beetles through the bung slit and into the each Jun of those years. Adult host range testing tubes and onto each test branch. The 3 beetles on field-collected T. sordida beetles was done in consisted of 1 mating pair and another beetle of 2009 after Japanese cooperators shipped the bee- undetermined gender due to the difficulty in de- tles during Jun of that year. Adults of both species termining gender in this flea beetle. Beetles were were set up in wooden screened sleeve cages, 50 monitored for 1 month, and at the end of each cm × 50 cm × 53 cm, and fed cut vines of the con- week, all leaves with feeding damage were trol plant, Paederia foetida, and its invasive rela- clipped, pressed and then scanned into jpeg files tive Paederia cruddasiana Pain. Paederia crud- to enable feeding to be measured with SigmaS- dasiana, native to Nepal, Burma, China, and can® Pro. Thailand (Puff 1991), is a naturalized weed in Mi- The most important finding of the research ami-Dade County, Florida. The beetles mated was the nearly equal or greater feeding by both readily and laid eggs throughout the sleeved rear- Trachyaphthona species on the native Florida ing cages. test plant virginiana L. (Table 1). Tra- The most likely potential non-target plants of chyaphthona nigrita adults ate a mean of 3.75 ± these beetles are the many native and economic 1.1 mm2 leaf material of D. virginiana, compared members of the Rubiaceae in Florida. The host to 4.76 ± 1.53 mm2 of leaf material on P. foetida,

Scientific Notes 113 SEA- HREE 2 . T OVER

FEEDING

****** CONDUCTED )SDSE

2 RECEIVED

* * * THAT

REPLICATES Trachyaphthona sordida Trachyaphthona ) mean (mm 2 5 PLANTS

TO

DUE

ARE SHOWING

FEEDING BEETLES

OF

. FLEA

* * 0.00 0.00 0.00 0.00 ** * ** 0.11* 0.00 * 0.04 * 0.00 0.04 0.04 0.00 0.01 0.02 0.01 0.00 0.01 0.01 BOLD

ADULT IN AMOUNTS

) SD SE total (mm 2 ARE

TOTAL

1 SORDIDA IN

NATIVES

Trachyaphthona nigrita Trachyaphthona ) mean (mm 2 LORIDA IFFERENCES 0.010.030.11 * * 3.33 * 0.02 0.671.150.012.79 0.37 * 0.230.00 * 0.56 0.22 0.18 0.00 0.16 0.10 0.45 0.00 0.09 0.00 0.67 0.15 0.12 0.06 0.21 0.22 0.12 0.28 0.16 F 16.5323.82 3.3118.76 4.76 0.57 3.75 1.53 0.33 1.10 0.88 0.64 4.15 4.84 9.70 1.38 1.61 0.63 3.23 0.82 0.36 0.50 0.47 0.29 . . D total (mm RACHYAPHTHONA T

SORDIDA SPECIES AND

T.

EACH

WITH

NIGRITA

FOR

Species MONTH 1 REPLICATES 3 Acuba japonica lanceolata Pentas Morinda citrifolia cruddasiana Paederia foetida Paederia Serissa foetida Diodea virginiana Ernodia littoralis Mitchella repens assurgens Spermacoce tetraquetra Spermacoce verticillata FOR

RACHYAPHTHONA T

VERSUS OF , TESTED

WERE

NIGRITA TESTING

T.

BEETLES

RANGE WITH

OST ADULT SONS 1. H Test feeding was documented in only 1 replicate of each species. 1 ABLE Cornales – Garryaceae Rubiales - Rubiaceae Hedyotideae Order—Family Tribe Order—Family Spermacoceae Spermacoceae Morindeae Paederieae Spermacoceae Spermacoceae Spermacoceae Paederieae Paederieae Spermacoceae T

114 Florida Entomologist 94(1) March 2011 and 3.31 ± 0.57 mm2 on P. cruddasiana. Tra- longs (Paederieae). These beetles, therefore, lack chyaphthona sordida adults consumed a mean of the appropriate level of host specificity, and this 3.23 ± 0.5 mm2 leaf material on D. virginiana, eliminates them from further consideration as po- compared to 1.61 ± 0.82 mm2 on P. foetida, and tential biological controls of Paederia foetida, 1.38 ± 0.63 mm2 on P. cruddasiana. Moreover, D. skunk vine. virginiana belongs to a taxonomic group within the Rubiaceae different than that of skunk vine, ACKNOWLEDGMENTS i.e., the tribe Spermacoceae rather than the tribe Paederieae for skunk vine. In addition, T. nigrita We thank Junichi Yukawa, Fukuoka University (re- caused what is considered to be more than test tired), and his students for collecting the Trachyaph- feeding on Spermacoce tetraquetra A. Rich., an- thona beetles in Japan and shipping them to Florida. other member of the Spermacoceae. Trachyaph- Rachel Taylor provided technical assistance and Luke thona nigrita adults consumed a mean of 0.56 ± Kasarjian grew the test plants. The South West Florida 2 Water Management District and the Florida Depart- 0.16 mm of S. tetraquetra, compared to 1.61 ± ment of Environmental Protection funded this research. 0.82 mm2 on P. foetida, and 1.38 ± 0.63 mm2 on P. cruddasiana. To prevent harm to native and im- REFERENCES CITED portant economic members of the Rubiaceae, the feeding of these flea beetles would need to be lim- FLORIDA EXOTIC PEST PLANT COMMITTEE. 2009. Florida ited to plants in the skunk vine tribe, the Paed- Exotic Pest Plant Council’s 2009 list of invasive spe- erieae. cies. Wildland Weeds 12: 13-16. It may be possible that the larvae of these bee- OKAMOTO, C., TUDA, K., YAMAGUCHI, D., SATO, S., PEM- tles could have greater specificity than the adults. BERTON, R. W., AND YUKAWA, J. 2008. Life history Two factors influenced our decision to cease re- traits and host specificity of Japanese Trachyaphtho- search on these Trachyaphthona species and to na species (Coleoptera: Chrysomelidae), candidates shift to other candidate insects of skunk vine. as biological control agents against skunk vine, Paed- eria foetida (Rubiaceae), in Southeastern United Most importantly, we have not successfully States and Hawaii. Entomol. Sci. (Japan) 11: 143-152. reared these univoltine beetles, which are, like PEMBERTON, R. W., AND PRATT, P. D. 2002. Skunk vine many root-feeding flea beetles, difficult to culture (Paederia foetida), pp. 343-351 In R. Van Driesche, B. in captivity. Secondly, our previous testing with Blossey, M. Hoddle, S. Lyon, and R. Reardon [eds.], the leaf beetle Sphenoraia rutilans found that it Biological Control of Invasive Plants in the Eastern could complete its development both on Diodia United States, U.S. Forest Service, Forest Health virginiana and Spermacoce tetraquetra, indicat- Technology Enterprise Team-2002-04, Morgantown, ing that these plants have an attractiveness and West Virginia. vulnerability to some Paederia feeding insects. PEMBERTON, R. W., MURAI, K., PRATT, P. D., AND TERA- MOTO, K. 2005. Dulinius conchatus (Hemiptera: Tingidae), considered and rejected as a potential bi- SUMMARY ological control agent of Paederia foetida, an inva- sive weed in Hawaii and Florida. Proc. Hawaiian En- Trachyaphthona nigrita and Trachyaphthona tomol. Soc. 37: 81-83. sordida, 2 potential biological control agents of PUFF, C. 1991. Revision of the genus Paederia in Asia, Paederia foetida L. (Rubiaceae), were collected pp. 207-289 In C. Puff [ed.], The Genus Paederia L. from Japan and brought into quarantine for adult (Rubiaceae–Paederieae): A Multidisciplinary Study, Opera Botanica Belgica 3. National Botanic Garden host specificity testing. Testing indicated that of Belgium. Meise, Belgium. they fed significantly on Florida native plants in USDA NATURAL RESOURCE CONSERVATION SERVICE. the tribe Spermacoceae, a different tribe from 2010. http://plants.usda.gov/java/noxious?rptType= that to which the target weed Paederia foetida be- State&statefips=12. Last accessed on 29 Oct 2010.