Final Report
Hawaii Invasive Species Council
Research and Technology Program
PCSU contract 54003
Project Title: Quarantine testing of an insect for biocontrol of Miconia calvescens
HISC Funds: $37,275
Principal investigator:

Tracy Johnson
Institute of Pacific Islands Forestry
USDA Forest ServiceP.O. Box 236
Volcano, Hawaii 96785
Ph: 808-967-7122
E-mail: tracyjohnson@fs.fed.us

Summary of project
The psyllid Diclidophlebia lucens for this project was imported from Costa Rica to theVolcano quarantine facility under USDA-APHIS-PPQ 526 permit #69048 between July andOctober 2005. A colony has been maintained on small potted Miconia calvescens and used
for experimental studies of host specificity and susceptibility to natural enemies. The insect
colony remains vigorous with no problems from disease or natural enemies over the past 2.5
years. Specificity tests of adult and larval D. lucens, completed in December 2007, indicate
this insect’s host range is restricted to the family Melastomataceae, members of which are allalien in Hawaii. Although D. lucens is probably acceptable for release for biocontrol basedon this restricted host range, its further development is currently assigned a low priority.
Potential impact of this agent on miconia appears limited, and its populations would likely besubject to control by psyllid enemies already present in Hawaii. A petition to release D.
lucens will not be submitted at this time. Instead other agents that appear to have greater
potential impacts on miconia will be developed ahead of D. lucens.
Timeline of this project was modified to accommodate hiring and training of quarantine
personnel. Write-up of specificity testing and other studies will be incorporated in amanuscript for publication later in 2008. Specific accomplishments of this project throughDecember 2007 are noted below.
Project Goals:1) Obtain host specificity data for and evaluate the suitability of Diclidophlebia lucens forrelease in Hawaii for biocontrol of Miconia calvescens.
Accomplishment: A total of 28 plant species were tested, beginning with many of thenaturalized melastomes found in Hawaii and including representatives of other related plantfamilies (Myrtaceae, Lythraceae, Onagraceae, Combretaceae, Thymelaeaceae) and someunrelated species. All tests indicate that host range of this insect is restricted the family
Melastomataceae (Figure 1). In particular, expected host range in Hawaii, based on ability of
the insect to feed and reproduce under quarantine conditions, includes Miconia calvescens,
Tetrazygia bicolor and Heterocentron subtriplinervium. Other melastomes may serve ashosts, but our tests suggest that their suitability is marginal. No plants outside the melastome
family would be expected to experience damage from this insect. Native and endemic plants
appear very unlikely to experience direct adverse effects from D. lucens.
2) Carefully screen the colony of Diclidophlebia to eliminate parasitic and pathogenic hitchhikers from Costa Rica.
Accomplishment: We initiated our lab colony with recently deposited eggs imported from a
Costa Rican lab colony. Resulting nymphs and adult were transferred to fresh plant material
in quarantine. No natural enemies have been encountered attacking eggs or nymphs of thisinsect in the field in Costa Rica. In particular, eggs held for possible emergence of tiny
hymenopteran parasitoids in Costa Rica have yielded no enemies. Our initial shipments of D.
lucens appeared to be enemy-free, and we are confident that the colony has remained so inHawaii.
3) Test adult feeding and oviposition preference in choice (M. calvescens present) and nochoice (M. calvescens absent) situations.
Accomplishment: No-choice tests of feeding and egg-laying by mature adults indicate thatthe potential host range of this insect is entirely restricted to the melastome family in Hawaii(Figure 1). Since none of these host plants are highly valued in Hawaii (in fact, most areweedy invaders), host preference under choice conditions were not examined. No-choicetests are regarded as highly conservative from the standpoint of screening against possible
non-target host use, since they tend to reveal the broadest possible host range, which
typically is not realized in actual field settings.
4) Test host specificity of immatures by exposing first instar nymphs to non-target plants
under no-choice.
Accomplishment: Testing of first instars proved unfeasible due to the fragility of eggs andyoung nymphs of this species. Therefore testing was conducted with third instars. Results
paralleled those of the adult tests (Figure 1): species most suitable for development ofimmature D. lucens are Miconia calvescens, Tetrazygia bicolor and Heterocentron
subtriplinervium.
5) Replicate all tests a minimum of four times.
Accomplishment: This objective has been met in all tests and appears to be a suitable levelof replication.
6) Evaluate the susceptibility of Diclidophlebia to known psyllid enemies in Hawaii (e.g.
Curinus coeruleus, Cryptolaemus montrouzieri) in quarantine under close confinementin petri dishes, as well as in cages on potted plants.
Accomplishment: Immature and adult Curinus coeruleus fed on eggs and nymphs of D.
lucens in quarantine tests. Lady beetles of this species did not attack adult psyllids, which are
more mobile than immature stages. Curinus coeruleus are widespread in Hawaii and areconsidered a primary constraint on outbreaks of the leucaena psyllid (Heteropsylla cubana),
which severely impacted leucaena (haole koa) prior to Curinus. Susceptibility of D. lucens toparasitoids in Hawaii has not been evaluated, however its susceptibility to this predatory lady
beetle alone could prove a major barrier to biocontrol of miconia by this agent.

7) Summarize data from quarantine tests and combine them with results of biological studies
completed in Costa Rica in a petition for release of Diclidophlebia in Hawaii.
8) Incorporate data on host specificity of Diclidophlebia and its susceptibility to natural
enemies into a formal petition for release.
9) Submit a formal petition for release to the Hawaii Department of Agriculture and USDAAPHIS within one month of completion of tests in quarantine.
Accomplishment: A formal petition for release of D. lucens will not be submitted at thistime. Evaluation of current data suggests that D. lucens should be assigned a low priority forrelease because its potential for impact on miconia appears limited, and its populations may
be subject to control by psyllid enemies already present in Hawaii. Because other agents
under consideration appear to have greater potential impacts on miconia, they will bedeveloped ahead of D. lucens. These include a stem boring weevil and several species thatattack flowers and fruit.
10) Submit host specificity and other biological data for publication in a peer-reviewed
journal such as "Biological Control."Accomplishment: A manuscript describing host specificity and other biological data for D.
lucens is in preparation and is expected to be submitted later this year. A description andbasic biology of this species was published in 2005:
Burckhardt, D., P. Hanson and L. Madrigal. 2005. Diclidophlebia lucens, n. sp. (Hemiptera:Psyllidae) from Costa Rica, a potential control agent of Miconia calvescens(Melastomataceae) in Hawaii. Proceedings of the Entomological Society of Washington
107: 741–749.

Figure 1.
Survival and egg-laying of Diclidophlebia lucens occurred only on melastomes in no-choice
host specificity tests in quarantine. Adult survival and egg-laying was scored after 2 weeks
exposure. Survival of nymphs to adulthood was scored within one month of placement of
third instars on test plants. On most non-melastomes, adult and immature psyllids died withina few days. Data represent means and standard errors of a minimum of 4 replicate tests.

FAMILYAdultSurvival

SPECIES
0.0

MyrtalesMelastomataceae

Myrtaceae

Lythraceae
Onagraceae
Combretaceae
Thymelaeaceae
Fabaceae
Myoporaceae
Sapindaceae
Dicksoniaceae

Miconia calvescens
Clidemia hirta
Tetrazygia bicolor
Dissotis rotundifolia
Medinilla cummingii
Melastoma candidum
Heterocentron subtriplinervium
Pterolepis glomerata
Tibouchina herbacea
Tibouchina urvilleana
Arthrostema ciliatum
Metrosideros polymorpha
Eugenia uniflora
Myrciaria cauliflora
Psidium cattleianum
Rhodomyrtus tomentosa
Syzygium jambos
Cuphea hyssopifolia
Lythrum maritimum
Epilobium ciliatum
Fuchsia magellanica
Terminalia catappa
Wikstroemia sandwicensis
Acacia koa
Sophora chrysophylla
Myoporum sandwicense
Dodonaea viscosa
Cibotium glaucum

0.20.4Eggs
Laid020 40 60 80

NymphSurvival
0.0 0.2 0.4 0.6

Figure 2. Diclidophlebia lucens attains high density of adults (orange) and nymphs(covered by wax filaments) when confined on miconia plants. Attacked shoots are stunted
but not killed. (Photos by Kenji Nishida)

Figure 3.
Tests in quarantine of susceptibility of Diclidophlebia lucens to Curinus coeruleus lady
beetles conducted by student intern Brenner Wai.