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Classical biocontrol can be an efficient method to manage invasive plants, although the effectiveness of biocontrol agents (BCAs) is highly variable. The role of plant defenses and their response to environmental gradients and herbivore damage, may partially explain this variability. Air potato ( Dioscorea bulbifera ) is a highly invasive plant in the USA, particularly in Florida . Lilioceris cheni  Gressitt and Kimoto 1961 (Coleoptera: Chrysomelidae), a specialist on D. bulbifera , successfully established as its BCA, although its efficacy varies across Florida. Phytochemicals in D. bulbifera , such as phenols or saponins, may mediate preference and performance of L. cheni. In the field, we recorded plant cover and beetle damage at thirteen populations across Florida. In the greenhouse, we conducted chemical and feeding bioassays by applying jasmonic acid (JA) and salicylic acid (SA) to D. bulbifera plants and recorded beetle damage, and quantified saponin and phenol production. We also conducted olfaction-based choice bioassays to determine beetle preferences. We found that beetle damage was negatively correlated with plant cover in the field and that damage and saponin levels were positively correlated. In the greenhouse, JA-treated plants had higher herbivory and saponin levels than SA-treated plants. JA-treated and Beetle damaged plants were also preferred in choice bioassays. These findings imply potential synergistic effects of BCA feeding through induction of plant defenses, which may inform the timing and frequency of BCA field releases. Our findings that induced plant defenses increase BCA feeding, and potentially their effectiveness, may apply more broadly because all approved BCA are highly specialized on their host plants. Therefore, interactions between invasive plants and their BCAs, and how they are mediated by plant defenses, deserve more attention as potential methods to increase the effectiveness of classical biocontrol.

The brilliant red Lilioceris merdigera (Coleoptera, Chrysomelidae) can spend its entire life cycle on the cardenolide-containing plant Convallaria majalis (lily of the valley) and forms stable populations on this host. Yet, in contrast to many other insects on cardenolide-containing plants L. merdigera does not sequester these plant toxins in the body but rather both adult beetles and larvae eliminate ingested cardenolides with the feces. Tracer feeding experiments showed that this holds true for radioactively labeled ouabain and digoxin, a highly polar and a rather apolar cardenolide. Both compounds or their derivatives are incorporated in the fecal shields of the larvae. The apolar digoxin, but not the polar ouabain, showed a deterrent effect on the generalist predatory ant Myrmica rubra, which occurs in the habitat of L. merdigera. The deterrent effect was detected for digoxin both in choice and feeding time assays. In a predator choice assay, a fecal shield derived from a diet of cardenolide-containing C. majalis offered L. merdigera larvae better protection from M. rubra than one derived from non-cardenolide Allium schoenoprasum (chives) or no fecal shield at all. Thus, we here present data suggesting a new way how insects may gain protection by feeding on cardenolide-containing plants.

Air potato, Dioscorea bulbifera L., is an invasive vine found in the southeastern United States and is native to Asia and Africa. The air potato leaf beetle Lilioceris cheni (Coleoptera: Chrysomelidae), is a host specific biological control agent introduced for D. bulbifera control. In this study, odor cues that control the attraction of L. cheni to D. bulbifera were investigated. The first experiment investigated the response of L. cheni to D. bulbifera leaves versus no leaves in the presence or absence of air flow. The experiment showed a significant response of L. cheni to D. bulbifera leaves in the presence of air flow with leaves placed upwind. When air flow and/or leaves were absent, L. cheni dispersed randomly between the upwind and downwind targets, indicating L. cheni uses volatiles from D. bulbifera in host selection. The second experiment investigated L. cheni response to undamaged, larval-damaged, and adult-damaged plants. Lilioceris cheni showed preference to move towards conspecific damaged plants compared to undamaged plants but did not discriminate between larvae-damaged or adult-damaged plants. The third experiment investigated volatile profiles of damaged D. bulbifera plants using gas chromatography coupled with mass spectroscopy. We found significant differences in volatile profiles between adult and larval damaged plants compared to mechanically damaged and undamaged plants, with increases in 11 volatile compounds. However, larval and adult-damaged volatile profiles did not differ. The information acquired during this study could be used to develop strategies to monitor for L. cheni and improve its biological control program.

The Chinese species of Lilioceris are revised, and three new species are described from Tibet, China: Lilioceris zhentangensis Xu & Liang, sp. nov. , Lilioceris medogensis Xu & Liang, sp. nov. and Lilioceris zayuensis Xu & Liang, sp. nov. Five species of Lilioceris are reported for China as new records: L. dromedarius (Baly, 1861), L. pulchella (Baly, 1859), L. semicostata (Jacoby, 1908), L. unicolor (Hope, 1831) and L. nepalensis Takizawa, 1989. Lilioceris seminigra (Jacoby, 1889) is proposed as a junior synonym of L. unicolor Hope, 1831. Redescriptions, habitus photographs, geographic distributions, host plants (if available) and habitats are provided for these species.

A new species group of Lilioceris Reitter, 1913 is proposed and reviewed, the semipunctata group. It includes eleven species: L. atrilateralis Kimoto & Takizawa, 1973, L. consentanea (Lacordaire, 1845), L. dentifemoralis Long, 1988, L. discrepens (Baly, 1879), L. jianfenglingensis Long, 1988, L. latissima (Pic, 1932), L. lianzhouensis Long, 2000a, L. rondoni Kimoto & Gressitt, 1979, L. rufometallica (Pic, 1923), L. semipunctata (Fabricius, 1801), and L. yuae Long, 2000b. Lilioceris discrepens and L. rondoni were new records from China. Two synonyms are proposed: Lilioceris xinglongensis Long, 1988, syn. nov. of L. consentanea (Lacordaire, 1845), and Crioceris rufimembris Pic, 1921, syn. nov. of L. semipunctata . An identification key, descriptions, habitus photographs, geographic distributions, host plants and habitats (if available), are provided for these species.

Insect damage to a plant activates induced defenses, which include releases of herbivore induced plant volatiles (HIPVs) that attract natural enemies and usually repel generalist herbivores. Oppositely, most herbivore specialists have evolved responses against these defenses, and in many cases are attracted to host HIPVs. However, it is not clear if a specialist is able to discriminate HIPVs released by conspecifics, other specialists, or generalist damage. Dioscorea bulbifera is an invasive vine native to Asia and Africa with infestations in the southeastern United States, Hawai’i, and Puerto Rico. A host specific biological control agent, Lilioceris cheni (Coleoptera: Chrysomelidae) was introduced in 2011 to control D. bulbifera. Recently, a new host specific biological control agent, Lilioceris egena, has been released to improve the biological control program for D. bulbifera. In this study, attraction of L. cheni to HIPVs from generalist, Spodoptera frugiperda (Lepidoptera: Noctuidae); specialist, L. egena; and conspecific damage were investigated. Behavioral assays indicated L. cheni had preference for any type of herbivore damaged plants compared to undamaged plants and discriminated between conspecific damaged plants in the presence of generalist damaged plants, favoring conspecific damaged plants. Differently damaged D. bulbifera plants were then evaluated using gas chromatography coupled with mass spectroscopy which revealed significant quantitative differences between both the specialists’ herbivore damage compared to the generalist volatile profiles with induction of 11 volatiles and suppression of four. This study highlights the importance of understanding an invasive plant’s response to specialist and generalist damage for better management of the invasive species.

Purposeful manipulation of biological control programs, such as timed releases of biological control agents, can be ephemeral and difficult to expand into new areas impacted by the targeted invasive plant. Integration of chemical ecology through attractive semiochemical lures to aggregate biological control agents to un-colonized areas can help mitigate this challenge. The invasive air potato vine, Dioscorea bulbifera L., is native to Asia and Africa with invasive infestations in the southeastern United States, Hawai’i, and Puerto Rico. In 2011, a host specific biological control agent, Lilioceris cheni (Coleoptera: Chrysomelidae), was introduced to manage D. bulbifera . Synthetic and racemic blends of previously identified attractive herbivory induced plant volatiles (HIPVs), ocimene and farnesene, were first evaluated for antennal response through electroantennography, then deployed as potential attractive lures in field conditions. Electroantennogram results validated the ability of adult male and female L. cheni to detect the two compounds. When used in field conditions, adult L. cheni beetles showed increased response to plants with ocimene and farnesene lures compared to control plants. The chemically enhanced lures increased L. cheni adult densities on D. bulbifera plants in the field compared to control plants. Plants with higher densities of L. cheni had greater direct herbivore feeding damage and observed cupped leaves, indicating the presence of oviposition and future larval development. The information gathered in this study indicated that the use of attractant semiochemical lures to purposefully aggregate and direct movement of biological control agents can improve the efficacy of invasive plant biocontrol programs.

Criocerine leaf beetles found in Nepal feeding on Dioscorea bulbifera (L.), an invasive weed of Asian origin, were identified as Lilioceris cheni Gressitt and Kimoto based on a synopsis of the Oriental Lilioceris species and review of the Lilioceris impressa species group. All the continental, Oriental species included in the group are diagnosed and illustrated, and a key for their identification is provided. Species status of Lilioceris thibetana Pic, 1916 is resurrected. The following new synonyms are proposed: Lilioceris coomani (Pic, 1928) = Lilioceris egena (Weise, 1922), and Lilioceris subcostata (Pic, 1921a), Lilioceris laticornis (Gressit, 1942), Lilioceris inflaticornis Gressit & Kimoto, 1961, and Lilioceris maai Gressit & Kimoto, 1961 = Lilioceris impressa (Fabricius, 1787). Lectotypes of the following species are designated: Lilioceris coomani Pic, 1928; Lilioceris impressa (Fabricius, 1787); Lilioceris laosensis (Pic, 1916); Lilioceris malabarica (Jacoby, 1904); Lilioceris ruficornis (Pic, 1921b); Lilioceris subcostata (Pic, 1921a); Lilioceris thibetana (Pic, 1916); and Lilioceris unicolor (Hope, 1831).

PFR-97 20% WDG (PFR-97) is a broad-spectrum entomopathogenic fungal biopesticide that contains the active ingredient Cordyceps javanica (Frieder. & Bally) Kepler, B. Shrestha & Spatafora (Hypocreales: Cordycipitaceae). This biopesticide is labelled for controlling aphids, psyllids, spider mites, thrips, and whiteflies in various crops, but also can infect certain chrysomelid species. Pest control activities applying PFR-97 in 1 agroecosystem may inadvertently drift and affect biological control agents purposefully released in another ecosystem. Therefore, our goal was to determine if PFR-97 was compatible when applied near Lilioceris cheni Gressitt and Kimoto (Coleoptera: Chrysomelidae), a chrysomelid biological control agent for the invasive air potato. The consumption and survival rates of adult beetles after exposure to PFR-97 were investigated via leaf bioassays. Thirty L. cheni adults were provisioned individually with a Dioscorea bulbifera L. (Dioscoreaceae) leaf sprayed with either a C. javanica suspension at the concentration of 106, 105, 103, or 102 blastospores per mL-1 or sterile distilled water (control) for 72 h. Untreated leaves were provided every 3 d for an additional 18 d and leaf consumption was determined. Results showed the survival and leaf consumption of the L. cheni adults did not differ among treatments and control. Overall, our study demonstrated that any inadvertent exposure of L. cheni adults to C. javanica via spray drift is unlikely to impact the performance of the adult biological control agents. PFR-97 20% WDG (PFR-97) es un bioplaguicida fungifero entomopa-tógeno de amplio espectro que contiene el ingrediente activo Cordyceps javanica (Frieder. & Bally) Kepler, B. Shrestha & Spatafora (Hypocreales: Cordycipitaceae). Este biopesticida está etiquetado para el control de áfidos, psílidos, araña rojas, trips y mosca blancas en varios cultivos, pero también puede infectar a ciertas especies de crisomélidos. Las actividades de control de plagas que aplican PFR-97 en 1 agroecosistema pueden derivar inadvertidamente y afectar a los agentes de control biológico liberados intencionalmente en otro ecosistema. Por lo tanto, nuestro ob-jetivo fue determinar si PFR-97 era compatible cuando se aplicaba cerca de Lilioceris cheni Gressitt and Kimoto (Coleoptera: Chrysomelidae), un agente de control biológico de crisomélidos para la papa aérea invasora, Dioscorea bulbifera L. (Dioscoreaceae). Se investigaron mediante bioen-sayos en hojas las tasas de consumo y sobrevivencia de escarabajos adultos después de la exposición a PFR-97. Se suministraron treinta adultos de L. cheni individualmente con una hoja de D. bulbifera rociada con una suspensión de C. javanica a una concentración de 106, 105, 103, or 102 blastosporas por mL-1 o agua destilada estéril (control) durante 72 h. Se proporcionaron hojas sin tratar cada 3 días durante 18 días adicionales y se determinó el consumo de hojas. Los resultados mostraron que la sobrevivencia y el consumo de hojas de los adultos de L. cheni no difirieron entre los tratamientos y el control. En general, nuestro estudio demostró que es poco probable que cualquier exposición inadvertida de adultos de L. cheni a C. javanica a través de la dispersión del rocío afecte el desempeño de los agentes de control biológico para adultos.

The air potato beetle, Lilioceris cheni Gressitt and Kimoto (Coleoptera:Chrysomelidae), is a successful biological control agent of the air potato vine, Dioscorea bulbifera L. (Dioscoreales: Dioscoreaceae), in the southern United States. Lilioceris cheni is currently being mass-reared by the Florida Department of Agriculture and Consumer Services Division of Plant Industry (FDACS-DPI) for biological control releases and research. The facility rears and releases over 50,000 adult beetles annually at approximately 1000 different locations. In addition to data on beetle production and distribution, studies on alternative larval and adult diets are described. Adults fed bulbils as the sole food source had reduced life spans compared with beetles given fresh air potato leaves. Adults survived without air potato leaves or bulbils for several days to two weeks depending on availability of leaves at emergence. Larvae did not survive on a modified artificial Colorado potato beetle diet containing fresh air potato vine leaves. Adults survived while consuming artificial diet but ceased oviposition. They, however, resumed egg laying less than one week after being returned to a diet of fresh air potato vine leaves.