@article {13293, title = {Foraging efficacy of the entomopathogenic nematode Steinernema riobrave in different soil types from California citrus groves}, journal = {Applied Soil Ecology}, volume = {45}, number = {3}, year = {2010}, month = {Jul}, pages = {243-253}, abstract = {Entomopathogenic nematodes (EPNs) are lethal insect parasites that develop inside the body of their insect host. The EPN Steinernema riobrave infects many different types of soil insects, including larvae of the invasive citrus root weevil, Diaprepes abbreviatus, which is a key pest in citrus production. Soil characteristics have a great impact on nematode foraging efficacy and therefore on the ability of EPNs to be used successfully in biological control programs. Our specific objectives were to: (1) survey for the presence of native EPNs in California citrus groves; and (2) identify soil parameters that would allow us to predict EPN efficacy. The long-term objective of this study is to develop biological control methods to address the invasion of the citrus root weevil, D. abbreviatus, into California using EPNs. We collected soils from 36 sites in California where citrus is produced commercially, sampled them for native nematode presence and tested the foraging efficacy (movement and host finding) of S. riobrave in these soils at three different soil depths; 100, 250 and 500 mm. Soil textures and physical characteristics were analyzed. We found five isolates of endemic EPNs (Heterorhabditis spp.) from southern California. Three were identified as Heterorhabditis bacteriophora, and two as Heterorhabditis sonorensis, which were recorded for the first time in California. S. riobrave{\textquoteright}s ability to infect hosts varied among soil types and depths. We also found significant correlations between soil characteristics (texture and physical characteristics) and S. riobrave foraging efficacy. Synthesis and applications. Our results and analyses can play a role in the prediction of S. riobrave success in various soil types. Perhaps more importantly, we suggest an approach to predict biological control potential based on soil characters that might be used with other insect pathogens. While soil texture is the main factor that affects EPN efficacy, we found that other parameters like organic matter level and dissolved solids are also important. [copyright]2010 Elsevier B.V. All rights reserved.}, keywords = {Diaprepes abbreviatus}, isbn = {0929-1393}, author = {Kaspi, Roy and Ross, Andrew and Hodson, Amanda K. and Stevens, Glen N. and Kaya, Harry K. and Lewis, Edwin E.} } @article {13049, title = {Thermal requirements of Fidiobia dominica (Hymenoptera: Platygastridae) and Haeckeliania sperata (Hymenoptera: Trichogrammatidae), two exotic egg parasitoids of Diaprepes abbreviatus (Coleoptera: Curculionidae)}, journal = {BioControl (Dordrecht)}, volume = {53}, number = {3}, year = {2008}, month = {June}, pages = {451-460}, type = {Article}, abstract = {Diaprepes abbreviatus is an exotic root weevil occurring in southern US. It is a highly polyphagous species which can complete its entire life cycle on citrus and several woody ornamental plants. The lack of native egg parasitoids for this weevil in citrus orchards has triggered efforts to evaluate candidate egg parasitoids from the Caribbean Region into Florida. The egg parasitoids Fidiobia dominica and Haeckeliania sperata are two exotic natural enemies of D. abbreviatus recently introduced in the US in a classical biological control program. The thermal requirements of both parasitoids were studied in the laboratory. The upper development threshold (UDT) of F. dominica was 30.0[degree]C, itsmaximal development rate (MDR) occurred at 27.6[degree]C, its lower development threshold (LDT) was 9.6[degree]C and its thermal constant (K) for development from egg to adult was 293.1 DD. For H. sperata, UDT was 35.0[degree]C, MDR occurred at 31.0[degree]C, LDT was around 15[degree]C and K was 188.1 DD. Based on these results, both species would be able to complete 17 to 18 generations annually in southern Florida. However, host availability during critical periods could severely impair the ability of these egg parasitoids to establish and successfully control D. abbreviatus in areas where winter temperatures fluctuate around 12[degree]C, the LDT for this pest.}, keywords = {Diaprepes abbreviatus}, isbn = {1386-6141}, author = {Jacas, Josep A. and Pena, Jorge E. and Duncan, Rita E. and Ulmer, Bryan J.} } @article {13050, title = {The role of Brachyufens osborni (Hymenoptera: Trichogrammatidae) in the classical biological control program against Diaprepes abbreviatus (Coleoptera: Curculionidae) in Florida}, journal = {Biological Control}, volume = {54}, number = {3}, year = {2010}, month = {Sep}, pages = {213-220}, abstract = {Brachyufens osborni is an indigenous egg parasitoid of weevil species laying concealed eggs in Florida. Diaprepes abbreviatus, an exotic weevil pest of different crops in the southern USA, has been reported as a host for B. osborni. In this study we investigated the interaction between B. osborni and D. abbreviatus as well as other hosts including Pachnaeus litus and Artipus floridanus. The thermal requirements of B. osborni and the interaction between this species and three other weevil parasitoids introduced in a classical biological control program against D. abbreviatus (Aprostocetus vaquitarum, Haeckeliania sperata and Quadrastichus haitiensis) were also examined in laboratory studies. Although B. osborni attacked eggs of all weevil species tested, it could not complete development on D. abbreviatus. The three exotic parasitoids did successfully develop on both P. litus and D. abbreviatus eggs, though our results showed that P. litus should not be considered as an alternative host for the introduced parasitoids during winter in central Florida. Because B. osborni cannot complete development on D. abbreviatus, it has never been recovered from field collected hosts, and its effect on D. abbreviatus in the field remains ignored. This study demonstrates that although B. osborni could not successfully develop in D. abbreviatus, it can inflict important mortality to it and suggests that B. osborni could impact the establishment of introduced D. abbreviatus egg parasitoids. [copyright] 2010 Elsevier Inc. All rights reserved.}, keywords = {Diaprepes abbreviatus}, isbn = {1049-9644}, author = {Jacas, Josep A. and Ulmer, Bryan J. and Duncan, Rita E. and Pena, Jorge E.} } @article {11287, title = {A modified method to visualize infection sites of spores of the entomopathogen Beauveria bassiana (Deuteromycotina: Hyphomycetes) on the exoskeleton of citrus root weevil Diaprepes abbreviatus (Coleoptera: Curculionidae) adults}, journal = {Florida Entomologist}, volume = {92}, number = {4}, year = {2009}, month = {December}, pages = {623-628}, abstract = {Beauveria bassiana is a widespread entomopathogen which is infectious to a great variety of insects. A commercial preparation of this fungus was used to study its potential as a biocontrol agent of the citrus root weevil, Diaprepes abbreviatus. Laboratory reared adult weevils were placed in clean plastic bags with 0.05 g of powdered inoculum per bag, shaken for thirty seconds, and placed in holding cages. In order to determine the spore concentration, germination, and position of ingress, inoculated weevils were dipped in a collodion solution after 30 min, 6 h, 12 h, 18 h, and 30 h. Collodion peels from various areas of the exoskeleton were removed, stained with lactophenol cotton blue, and observed microscopically. At 12 h post-inoculation spores began to swell, and at 18 h close to 25\% germinated on all body parts except on the elytra. After 30 h, between 45\% and 75\% of the spores germinated, depending on the body part. Most active spore germination occurred around the eyes (75\%), followed by the ventral abdomen (65\%), the dorsal pronotum (60\%), scales (45\%), and dorsal surface of the elytra (7\%). Spores were washed from the surface of inoculated weevils with distilled water and plating onto potato dextrose agar. Spore density on the weevils{\textquoteright} surface was determined to be 15,815 [plus or minus] 479 spores initially after inoculation, and was reduced to 5,782 [plus or minus] 136 spores after 3 h.}, keywords = {Diaprepes abbreviatus}, isbn = {0015-4040}, author = {Gillett-Kaufman, Jennifer L. and Kimbrough, James W.} } @article {10835, title = {Entomopathogenic nematodes, root weevil larvae, and dynamic interactions among soil texture, plant growth, herbivory, and predation}, journal = {Journal of Invertebrate Pathology}, volume = {109}, number = {1}, year = {2012}, month = {Jan}, pages = {134-142}, abstract = {Greenhouse experiments were conducted to assess the influence of soil texture on the persistence, efficacy and plant protection ability of entomopathogenic nematodes (EPNs) applied to control larvae of the Diaprepes root weevil (DRW), Diaprepes abbreviatus, infesting potted citrus seedlings. Seedlings were grown in pots containing either coarse sand, fine sand, or sandy loam. Three DRW larvae were added to each of 80 pots of each soil type. 24 h later, 20 pots of each soil type that had received weevil larvae were inoculated with EPN infective juveniles (Us) of one of the following species: Steinemema diaprepesi, Steinernema riobrave and Heterorhabditis indica. Pots of each soil without EPNs were established as controls with DRW and controls without DRWs. Subsequently, pots with larvae received three additional larvae monthly, and the experiment continued for 9 months. Plant root and top weights at the end of the experiment were affected by both soil (P <= 0.0001) and nematodes (P <= 0.0001), and nematode species protected plants differently in different soils (interaction P <= 0.0001). Soil porosity was inversely related to plant damage by DRW, whether or not EPNs were present; and porosity was directly related to the level of plant protection by EPNs. Mortality of caged sentinel weevil larvae placed in pots near the end of the experiment was highest in pots treated with S. diaprepesi. In a second, similar experiment that included an additional undescribed steinernematid of the Steinemema glaseri-group, soil type affected root damage by DRW and root protection by EPNs in the same manner as in the first experiment. Final numbers of S. diaprepesi and Steinemema sp. as measured by real-time PCR were much greater than those of S. riobrave or H. indica in all soils. Across all treatments, the number of weevil larvae in soil at the end the experiment was inversely related to soil porosity. In all soils, fewer weevil larvae survived in soil treated with S. diaprepesi or Steinemema sp. than in controls with DRW or treatments with S. riobrave or H. indica. The results of these experiments support the hypothesis that EPNs provide greater protection of seedlings against DRW larvae in coarse textured soil than in finer textured soil. However, less vigorous growth of the control without DRW seedlings in the two finer textured soils suggests that unidentified factors that stressed seedlings in those soils also impaired the ability of seedlings to tolerate weevil herbivory. (C) 2011 Elsevier Inc. All rights reserved.}, keywords = {Diaprepes abbreviatus}, isbn = {0022-2011}, author = {El-Borai, Fahiem E. and Stuart, Robin J. and Campos-Herrera, Raquel and Pathak, Ekta and Duncan, Larry W.} } @article {10785, title = {Mitotic and meiotic studies of seven Caribbean weevils: difference of sex bivalent compaction at pachynema between Curculionidae and Dryophthoridae (Insecta: Coleoptera) species}, journal = {Comparative Cytogenetics}, volume = {2}, number = {1}, year = {2008}, month = {2008}, pages = {7-20}, type = {Article}, abstract = {The mitotic and meiotic karyotypes of seven species of Caribbean weevils are reported. Three species belong to the Dryophthoridae and four to the Curculionidae families. All are considered as pests for agriculture, and were formerly classified among Curculionidae. The three mitotic karyotypes of the Dryophthoridae species differ in their chromosome number and morphology while those of the four Curculionidae species are fairly similar and can be distinguished by heterochromatin variations or NOR location only. Diakineses/Metaphases I of all species exhibit a parachute sex bivalent and the same range of autosomal bivalent compaction. At contrast, at the pachytene stage, bivalents appear less compact in Curculionidae than in Dryophthoridae species, and this difference is particularly clear for the sex bivalent: at early-mid pachytene stage, chromosomes X and Y are elongated and in end-to-end association in Curculionidae while they form a rounded dense body in Dryophthoridae species. In both conditions, the sex chromosomes are embedded in argyrophilic proteins. The different compactions of the sex chromosomes do not depend on NOR location, either on the X or autosome(s). Thus, bivalent compaction kinetic and/or structure at pachynema may be a taxonomic character, which would give arguments for the split of Curculionidae into two families.}, keywords = {Cosmopolites sordidus, Diaprepes abbreviatus, Diaprepes marginicollis, Exophthalmus famelicus, Exophthalmus quadritaenia, Metamasius hemipterus, Rhynchophorus palmarum.}, isbn = {1993-0771}, author = {Dutrillaux, A. M. and Xie, H. and Dutrillaux, B.} } @article {9860, title = {Effect of host plants on successful parasitism by Haeckeliania sperata (Hymenoptera: Trichogrammatidae) on Diaprepes abbreviatus (Coleoptera: Curculionidae) eggs}, journal = {Environmental Entomology}, volume = {37}, number = {6}, year = {2008}, month = {December}, pages = {1565-1572}, type = {Article}, abstract = {Diaprepes abbreviates L. is a highly polyphagous root weevil that causes damage to several fruit crops, ornamental plants, and other naturally occurring plants in Florida. Haeckeliania sperata Pinto is a gregarious endoparasitoid that attacks D. abbreviates eggs. We hypothesized that the reproductive success of H. sperata is affected by the host plant of D. abbreviates. Six host plants with varying degrees of pubescence were used to determine the effect of leaf trichomes on the searching behavior and success of parasitism by H. sperata. No-choice tests showed that H. sperata was able to parasitize Diaprepes eggs laid on the six host plants. However, the plants with a high trichome density on their leaves had a lower percent of parasitism than the plants with smoother leaves. Removing trichomes from a host plant showed that the presence of some leaf trichomes had a negative effect on the overall searching efficiency of H. sperata. The presence of trichomes decreased the total distance traveled and increased the total search time of IT sperata females, resulting in a lower searching speed. Multiple regression analysis was used to establish the relationship between percent parasitism and leaf trichome density, leaf thickness, and the searching speed of H. sperata. Searching speed was the best predictor of percent parasitism; this parameter could be used to predict the suitability of host plants for the establishment of H. sperata. Our findings suggest that the reproductive success of H. sperata is affected by the host plant of D. abbreviatus.}, keywords = {Diaprepes abbreviatus}, isbn = {0046-225X}, author = {Carrillo, Daniel and Pena, Jorge E. and Capinera, John L.} } @article {9096, title = {Mitochondrial nucleotide variability in invasive populations of the root weevil Diaprepes abbreviatus (Coleoptera: Curculionidae) of Florida and preliminary assessment of Diaprepes sp. from Dominica}, journal = {Journal of Economic Entomology}, volume = {101}, number = {4}, year = {2008}, month = {August}, pages = {1443-1454}, type = {Article}, abstract = {Diaprepes abbreviatus (L.) (Coleoptera: Curculionidae) is a root weevil introduced into the United States from the Caribbean in 1964. It is associated with >300 plants, including citrus, sugarcane, and potatoes. D. abbreviatus is widespread in Florida, and it has recently been detected in limited areas of California and Texas. The purpose of this research is to evaluate the utility of 16S ribosomal (16S rRNA) and cytochrome oxidase I (COI) mitochondrial markers for the delineation of genetic populations of D. abbreviatus in Florida and for the characterization of patterns of dispersion among these populations. We also assessed these markers as genetic tools for the clarification of taxonomic uncertainties in specimens from Dominica (Lesser Antilles). We analyzed 111 weevils from six Florida populations and six specimens from Dominica. In Florida, we found three haplotypes with only one haplotype in each population. Florida haplotypes differed by one to three nucleotide substitutions, possibly the result of a recent divergence from one source population or three different introductions from closely related populations from the Caribbean. In contrast, specimens from Dominica showed a high genetic variability with three 16S haplotypes and six unique COI haplotypes, delineating two mitochondrial clades. We show that these mitochondrial markers are useful for phylogeographic studies of D. abbreviatus.}, keywords = {Diaprepes, Diaprepes abbreviatus}, isbn = {0022-0493}, author = {Ascunce, Marina S. and Ernst, Joel A. and Clark, Annemarie and Nigg, Herbert N.} } @article {8959, title = {Constitutive and induced subterranean plant volatiles attract both entomopathogenic and plant parasitic nematodes}, journal = {Journal of Ecology}, volume = {99}, number = {1}, year = {2011}, month = {January}, pages = {26-35}, abstract = {Indirect plant defences are well documented for the above-ground constituents of plants. Although less investigated to date, below-ground defences that mediate multitrophic interactions are equally important. Entomopathogenic nematodes (Steinernema diaprepesi) are attracted to herbivore- induced volatiles from Swingle var. (Citrus paradisi [center dot] Poncirus trifoliata) when fed upon by root weevil, Diaprepes abbreviatus. 2. We examined the extent to which below-ground volatiles modify behaviour of nematode species representing various foraging strategies (cruisers versus ambushers) and trophic levels (plant parasites versus entomopathogens). We compared attraction to volatiles of weevil-infested and non-infested roots from Swingle citrus rootstock and a parent line of the Swingle hybrid, Poncirus trifoliata (Pt). 3. Swingle weevil-infested roots attracted more nematodes than non-infested roots irrespective of nematode foraging strategy and trophic status. The parental line, Pt, attracted all nematode species irrespective of insect herbivory. 4. Dynamic in situ collection and GC[long dash]MS analysis of volatiles from soil revealed that Pt roots release attracting cues constitutively. A different non-hybrid citrus species (sour orange, Citrus aurantium) released nematode attracting cues only in response to larval feeding, similar to responses found in Swingle. Volatile collections from above- and below-ground portions of citrus plants revealed that above-ground feeding by weevils does not induce production of nematode attracting cues analogous to that induced by root damage, nor does damage by larvae below-ground induce a similar volatile above ground. 5. Synthesis. Our results suggest that release of nematode attractants by citrus roots occurs broadly and can be constant or herbivore-induced. The major constituent of this indirect defence is produced by roots and not shoots and in response to below-ground, but not above-ground herbivory. Our findings suggest that this cue acts on nematode species broadly, attracting entomopathogenic nematodes that exhibit various foraging strategies. Unexpectedly, we also found that this cue attracts a plant parasitic nematode species. It appears, thus, that release of nematode attracting cues by citrus plants can cause ecological costs. The plants, however, appear to counteract against these costs, because constitutive release was found only in a cultivar that is resistant to phytopathogenic nematodes, while herbivore-induced release occurred in lines susceptible to pathogenic nematode species.}, keywords = {Diaprepes abbreviatus}, isbn = {0022-0477}, author = {Ali, Jared G. and Alborn, Hans T. and Stelinski, Lukasz L.} } @article {8585, title = {LEAF GAS EXCHANGE AND DAMAGE OF MAHOGANY AND POND APPLE TREES FROM ADULT DIAPREPES ABBREVIATUS (COLEOPTERA: CURCULIONIDAE) FEEDING AND SOIL FLOODING}, journal = {Florida Entomologist}, volume = {94}, number = {3}, year = {2011}, month = {Sep}, pages = {655-668}, abstract = {The effects of feeding on leaves by adult Diaprepes root weevil, Diaprepes abbreviatus L. (Coleoptera: Curculionidae), and flooding on leaf gas exchange (net CO2 assimilation (A), transpiration (E), and stomatal conductance (g,)), plant growth (root, stem, leaf, and total plant dry weights, stem diameter, and plant height) and adult host plant preference (feeding damage and oviposition) were determined on mahogany, Swietenia mahagoni Jacq., and pond apple, Annona glabra L., trees in outdoor screen cages. Flooding reduced leaf gas exchange, plant growth, and D. abbreviatus feeding damage of mahogany trees. Leaf gas exchange of infested and non-infested trees of both mahogany and pond apple were similar except for one measurement date for mahogany. Leaf dry weights were greater for non-infested than infested mahogany trees. There was no effect of infestation on dry weights of pond apple trees. Based on feeding injury to leaves, adults preferred non-flooded to flooded mahogany trees. The lack of response in leaf damage or oviposition to flooding for pond apple was attributable to the avoidance of leaves by adult D. abbreviatus of this plant species despite it being a host for root weevil larvae. The results indicate that while flooding of the root zone adversely affects growth and physiology of mahogany trees, it does not predispose trees to greater damage from adult D. abbreviatus. In fact, adult insect damage was greater for non-flooded than flooded trees. Pond apple was not greatly affected by root zone flooding and was not a preferred host of adult D. abbreviatus under flooded or non-flooded conditions.}, keywords = {Diaprepes abbreviatus}, isbn = {0015-4040}, author = {Martin, Cliff G. and Mannion, Catharine and Schaffer, Bruce} } @article {8584, title = {LEAF GAS EXCHANGE AND GROWTH RESPONSES OF GREEN BUTTONWOOD AND SWINGLE CITRUMELO TO DIAPREPES ABBREVIATUS (COLEOPTERA: CURCULIONIDAE) LARVAL FEEDING AND FLOODING}, journal = {Florida Entomologist}, volume = {94}, number = {2}, year = {2011}, month = {Jun}, pages = {279-289}, abstract = {Effects of flooding and herbivory by Diaprepes abbreviatus L. (Coleoptera: Curculionidae) larvae on leaf gas exchange (net CO2 assimilation (A), transpiration (E), and stomatal conductance (gs)) and growth of green buttonwood (Conocarpus erectus L.) and Swingle citrumelo (Poncirus trifoliata (L.) Raf. x Citrus paradisi Macf.) trees were tested. Growth and survival of the larvae were also examined. For each plant species, there were 2 larval infestation treatments (infested and non-infested) and 2 flooding treatments (flooded and non-flooded). Beginning 6 d after larval infestation, plants were flooded in three 1-wk cycles each with 2 d of flooding followed by 5 d of non-flooding. For green buttonwood, E was higher for non-flooded than flooded plants on the third of 5 measurement dates and A and gs were higher for non-flooded than flooded plants on the fifth (final) measurement date. For Swingle citrumelo, E and gs were higher for non-infested than infested plants on the fifth (final) measurement date. Root dry weight of Swingle citrumelo was higher for flooded, infested than for non-flooded, infested plants and for non-flooded, non-infested than for non-flooded, infested plants. Larval survival rate, head capsule width, and root damage rating of Swingle citrumelo were lower for flooded than for non-flooded plants, whereas flooding did not affect larval survival or growth on green buttonwood. Thus, short-term cyclical flooding of three 2-d cycles may control D. abbreviatus larvae on Swingle citrumelo but did not control larval populations or reduce damage on green buttonwood.}, keywords = {Diaprepes abbreviatus}, isbn = {0015-4040}, author = {Martin, Cliff G. and Mannion, Catharine and Schaffer, Bruce} } @article {8582, title = {SURVIVAL OF DIAPREPES ABBREVIATUS (COLEOPTERA: CURCULIONIDAE) LARVAE ON GREEN BUTTONWOOD TREES IN FLOODED MARL SOIL AND POTTING MEDIUM}, journal = {Florida Entomologist}, volume = {93}, number = {2}, year = {2010}, month = {Jun}, pages = {153-160}, abstract = {Survival of Diaprepes root weevil Diaprepes abbreviates (L.) (Coleoptera: Curculionidae) larvae was assessed in flooded marl soil and a flooded nursery potting medium with green buttonwood (Conocarpus erectus L., Combretaceae) as a food source for the larvae. Root-zone flooding may be a viable control option for flood-tolerant ornamental plants including buttonwood. Significantly more larvae survived after 38 d in non-flooded than in flooded marl soil. Similarly, more larvae survived in non-flooded than in flooded potting medium; no larvae were recovered from flooded potting medium. Larval survival rates were significantly higher in flooded marl soil than in flooded potting medium, but there was no difference in survival between non-flooded marl soil and non-flooded potting medium. Larvae recovered from flooded marl soil had significantly smaller head capsule widths and probably were at least 1 instar younger than larvae recovered from non-flooded marl soil or non-flooded potting medium. In summary, flooding marl soil or potting medium reduced survival, and in marl soil flooding slows the growth of D. abbreviatus larvae.}, keywords = {Diaprepes abbreviatus}, isbn = {0015-4040}, author = {Martin, Cliff G. and Mannion, Catharine M. and Schaffer, Bruce} }