Potential Biological Control Agent Research Articles

Trichopria anastrephae as a Biological Control Agent of Drosophila suzukii in Strawberries.

In South America, the resident pupal parasitoid Trichopria anastrephae Costa Lima (Hymenoptera: Diapriidae) is a potential biological control agent of the pest Drosophila suzukii Matsumura (Diptera: Drosophilidae). In the present study, we (1) examined the behavior of T. anastrephae towards different host (D. suzukii) and host-substrate (strawberry) cues in choice and non-choice bioassays in laboratory, and (2) examined the density-dependent parasitism of T. anastrephae in D. suzukii-infested strawberries in a greenhouse. When given a choice, female parasitoids walked longer over chambers with fruits infested with eggs, larvae, or pupae of D. suzukii, when compared to healthy uninfested strawberries, and over overripe fruits when compared to unripe or ripe fruits. In the greenhouse assay, we observed an increase in parasitism and a decrease in the number of D. suzukii emerging per fruit with an increase in the number of parasitoids released. Our results allow a better understanding of the behavior and parasitism of T. anastrephae in D. suzukii-infested strawberries and provide useful data for potential biological control programs using this parasitoid.

New morphological and biological contributions to adults and immature forms of Pissonotusparaguayensis (Fulgoromorpha, Delphacidae) in wetlands of Argentina.

In the search for insects as biological control agents for the water primrose, the delphacid Pissonotusparaguayensis (Delphacidae) was found on Ludwigiagrandiflorasubsp.hexapetala (Onagraceae) in a wetland of Central East Argentina. The morphology of the unknown females (brachypterous and macropterous) and immature stages are described and illustrated. Adults and nymphs were collected in wetlands of Del Plata River Basin, from Buenos Aires to the northeastern part of Argentina. A rearing methodology was developed to perform biological studies. Both winged forms and structural features of the female genitalia are described for the first time at the genus level. Eggs and immature stages are described and keyed; fifth nymphal instars may be easily recognised by the yellowish colouration, blackish on dorsal of head, thorax and abdomen with conspicuous yellowish pits, ventrally only darkened on base of frons extended to lower level of eyes and dorsal surface of antennomeres I and II, and legs with distinctive black marks at femoro-tibial joint and apex. The geographical distribution is updated, expanding its range into Argentina, making Buenos Aires the southernmost limit of the genus in America. Biological information of the species is also reported here: life cycle, fecundity, oviposition behaviour, and host plant. Field observations showed that P.paraguayensis breeds, feeds, and causes damage to L.g.subsp.hexapetala. This delphacid presents a certain degree of specificity to the Ludwigia species in the Jussiaea section in host specificity tests. More studies are required to test this species as a potential biological control agent.

A parasitoid regulates 20E synthesis and antibacterial activity of the host for development by inducing host nitric oxide production.

Parasitoids are important components of the natural enemy guild in the biological control of insect pests. They depend on host resources to complete the development of a specific stage or whole life cycle and thus have evolved towards optimal host exploitation strategies. In the present study, we report a specific survival strategy of a fly parasitoid Exorista sorbillans (Diptera: Tachinidae), which is a potential biological control agent for agricultural pests and a pest in sericulture. We found that the expression levels of nitric oxide synthase (NOS) and nitric oxide (NO) production in host Bombyx mori (Lepidoptera: Bombycidae) were increased after E. sorbillans infection. Reducing NOS expression and NO production with an NOS inhibitor (NG-nitro-L-arginine methyl ester hydrochloride) in infected B. mori significantly impeded the growth of E. sorbillans larvae. Moreover, the biosynthesis of 20-hydroxyecdysone (20E) in infected hosts was elevated with increasing NO production, and inhibiting NOS expression lowered 20E biosynthesis. More importantly, induced NO synthesis was required to eliminate intracellular bacterial pathogens that presumably competed for shared host resources. Inhibiting NOS expression down-regulated the transcription of antimicrobial peptide genes and increased the number of bacteria in parasitized hosts. Collectively, this study revealed a new perspective on the role of NO in host-parasitoid interactions and a novel mechanism for parasitoid regulation of host physiology to support its development.

Potential Biological Control Agents against Soft Rot Diseases Caused by Pectobacteria on Some Sugar Beet Cultivars

Sugar beet is one of the most economically important agricultural crops cultivated in many provinces of Turkey. Especially in recent years, there has been an increase in bacterial tuber rot due to factors related to climate change. In preliminary trials, soft rot disease by Pectobacterium caratovorum subsp. caratovorum (Pcc) and Pectobacterium betavasculorum (Pb) were detected predominantly in sugar beets in Central Anatolia. Today, some cultural measures and copper compounds are used against soft rot agents in sugar beet, but successful results cannot be obtained in preventing the disease. In this study, a total of 270 soil samples were taken from the rhizosphere of 10 different fields in 3 different periods in 3 different ecologically diverse districts (Çumra, Altınekin and Seydişehir) of Konya, one of the provinces with the highest amount of sugar beet production in Turkey. As a result of the isolations, a total of 3064 bacterial isolates were purified and 262 of them showed antibacterial activity against Pcc and Pb in vitro conditions. In addition, 15 antagonist bacteria with the highest inhibitory effect on the development of both pathogens were tested in greenhouse conditions, and according to the results obtained from here, 3 antagonists with the highest effect were tested in field conditions in the cultivation areas of 3 different districts named above. Biochemical, morphological and molecular diagnoses of antagonist bacteria with high efficacy were made. According to the results obtained, it has been concluded that rhizospheric bacteria with antagonistic effect have a success rate of 33-90% against Pcc and Pb pathogens, and that the biological products to be prepared in future studies can be used in ecological, climate friendly and within sustainable agricultural practices in sugar beet production areas.

Additional host range testing of Eucryptorrhynchus brandti (Coleoptera: Curculionidae) for the biological control of tree-of-heaven, Ailanthus altissima (Simaroubaceae) in the U.S.A.

ABSTRACT Ailanthus altissima, native to China, is a highly invasive plant in North America, Europe, and other continents. This species displaces native plants by forming dense clonal thickets. Ailanthus altissima is shade intolerant, quickly invades fields, rights-of-way, urban areas, and areas in forests disturbed by logging, fire, or pests. This species is also a primary host of the economically damaging spotted lanternfly, Lycorma delicatula, recently introduced into the U.S. Eucryptorrhynchus brandti is native to China and has been identified as a potential biological control agent of A. altissima. Oviposition studies conducted on 11 non-target plant species demonstrated that E. brandti oviposited only on the U.S. native Leitneria floridana. All non- Leitneria species had adult feeding of less than 2% compared to A. altissima, with no oviposition or larval development. Longevity of E. brandti in no-choice tests with L. floridana and L. pilosa subsp. ozarkana, was shorter and the weevils consumed less foliage compared to A. altissima. Seventeen percent of the L. floridana trees tested had larval feeding and 18 E. brandti adults emerged from 10 replicates. No L. floridana trees with larval feeding died. All the A. altissima trees with larval development died. Eucryptorrhynchus brandti is projected to be an effective agent against A. altissima and pose no significant risk to native North American plant species, with potential to be an additional management tool for the spotted lanternfly.

Isolation and Molecular Characterization of Brotowali (Tinospora crispa) Rhizosphere Bacteria Producing Siderophore from Dry Lands of Lombok Island

In the context of biopesticide development, siderophore-producing rhizosphere bacteria play an important role as potential biological control agents. Siderophores are complex organic compounds produced by microorganisms to bind and take up iron ions (Fe3+) from the surrounding environment. This compound is very important because iron is a nutrient necessary for life for many microorganisms and plants. The aim of this research was to determine the type and ability of bacteria in the rhizosphere of Brotowali (Tinospora crispa) to produce siderophores. The method used in this research is an exploratory descriptive type. The isolation results obtained from the North Lombok area obtained 5 samples with codes B4A1, B6A1, BT61, BT63 and BT83. The results of the bacterial isolate potency test with Media Kings showed that only isolate BT63 showed clear fluorescence when exposed to ultraviolet light. Meanwhile, the Arnow's Assay test showed that only BT63 colonies experienced a color change to pink. The results of the molecular identification of the potential bacteria, namely BT63, using the BLAST method using the GenBank data base at NCBI, show that it is closely related to the species Bacillus thuringiensis strain FDAARGOS 791. The results above show that the rhizobacteria isolated from Brotowali have the potential to be developed as a natural biopesticide that can be applied in the future.

Susceptibility of adult Phlyctinus (Coleoptera: Curculionidae) to entomopathogens: A first look at potential differences in a newly revised species complex

AbstractPhlyctinus callosus and P. xerophilus (Coleoptera: Curculionidae) are two cryptic species of native entimine weevils, previously grouped together under the P. callosus sensu lato concept, that are pests of economic importance to the deciduous fruit and vine industry in the Western Cape province of South Africa. Laboratory bioassays were conducted using entomopathogenic fungi (EPF) isolates of Beauveria and entomopathogenic nematodes (EPNs), Heterorhabditis indica and Steinernema yirgalemense, to determine differences in susceptibility of adult P. callosus and P. xerophilus to potential biological control agents. The test arena used was 24‐well bioassay plates with an inoculation rate of 200 infective juveniles (IJs)/insect for EPNs and 5 × 105 conidia/insect for EPF. Insects were inoculated using a 12.7 mm filter paper impregnated with 50 μL of entomopathogen suspension. Infection was determined after 96 h incubation for EPNs through dissection of cadavers. Insects inoculated with EPF were incubated in the wells for 18 days and mortality recorded daily. Cadavers were surface sterilized and observed for overt mycosis. Differential susceptibility between P. callosus and P. xerophilus was observed in EPF but not in EPN bioassays. Differential susceptibility to EPF could be due to methodology. Low adult weevil pathogenicity was found for all entomopathogens, with variable results obtained from different bioassay batches.

Host range, biology, and climate suitability of Callopistria exotica, a potential biological control agent of Old World climbing fern (Lygodium microphyllum) in the USA

Old World climbing fern, Lygodium microphyllum (Cav.) R. Br., is one of the worst environmental weeds of southern and central Florida. The weed climbs over other plants, forming thick mats that block sunlight to native shrubs and trees. In the introduced range, Old World climbing fern invades much of the southern peninsula of Florida where cost-effective, sustainable control methods are needed. A potential biological control agent, the defoliating moth Callopistria exotica Guenee, was collected in Hong Kong and examined in quarantine to determine if it was safe for release. Climate modeling analysis was also performed to predict the potential climate suitability of C. exotica in the invaded range. A series of no-choice tests was conducted on 68 plant species from 45 genera, 33 plant families, and 18 orders. The results indicated that C. exotica is highly specific to the target weed, L. microphyllum and a congener that is also an exotic invasive, L. japonicum. The results indicated that the neonates fed and matured to the adult stage on the target weed L. microphyllum (0.71 ± 0.02 proportion survived) and on another invasive fern, L. japonicum (0.84 ± 0.04 proportion survived). No C. exotica neonates survived when fed the non-target species L. oligostachyum. A low proportion survived to the adult stage when fed the non-targets L. palmatum (0.07 ± 0.03), L. venustum (0.01 ± 0.01), and L. volubile (0.07 ± 0.03). Additionally, the few larvae that survived to the adult stage when fed L. palmatum and L. volubile had longer development times (130–150 % longer) and lower pupal weights (70–90 % lower) than those fed the target weed. All neonates perished within 3 days when fed the remaining 62 species evaluated in these no-choice tests. Climate modeling indicated that the suitability of North American climates for the establishment of C. exotica are very high in south Florida but are very unsuitable north of the L. microphyllum invaded range. These results indicated that this potential biological control agent is highly specific to L. microphyllum and L. japonicum and will have no, or very low survival on other non-target species. The release of C. exotica is expected to assist in the effort to manage the invasive weed Old World climbing fern.

Phylogenetic analyses reveal multiple new stem-boring Tetramesa taxa (Hymenoptera: Eurytomidae): implications for the biological control of invasive African grasses

Many native South African grass species have become invasive elsewhere in the world. The application of biological control to invasive grasses has been approached with trepidation in the past, primarily due to concerns of a perceived lack of host specific herbivores. This has changed in recent times, and grasses are now considered suitable candidates. The Tetramesa Walker genus (Hymenoptera: Eurytomidae) has been found to contain species that are largely host specific to a particular grass species, or complex of closely related congeners. Very little taxonomic work exists for Tetramesa in the southern hemisphere, and the lack of morphological variability between many Tetramesa species has made identification difficult. This limits the ability to assess the genus for potential biological control agents. Species delimitation analyses indicated 16 putative novel southern African Tetramesa taxa. Ten of these were putative Tetramesa associated with Eragrostis curvula (Schrad.) Nees and Sporobolus pyramidalis Beauv. and S. natalensis Steud., which are alien invasive weeds in Australia. Of these ten Tetramesa taxa, eight were only found on a single host plant, while two taxa were associated with multiple species in a single grass genus. The Tetramesa spp. on S. pyramidalis and S. africanus were deemed suitably host-specific to be used as biological control agents. Field host range data for the Tetramesa species on E. curvula revealed that the wasp may not be suitably host specific for use as a biological control agent. However, further host specificity testing on non-target native Australian species is required.

A small step to discover candidate biological control agents from preexisting bioresources by using novel nonribosomal peptide synthetases hidden in activated sludge metagenomes.

Biological control agents (BCAs), beneficial organisms that reduce the incidence or severity of plant disease, have been expected to be alternatives to replace chemical pesticides worldwide. To date, BCAs have been screened by culture-dependent methods from various environments. However, previously unknown BCA candidates may be buried and overlooked because this approach preferentially selects only easy-to-culture microbial lineages. To overcome this limitation, as a small-scale test case, we attempted to explore novel BCA candidates by employing the shotgun metagenomic information of the activated sludge (AS) microbiome, which is thought to contain unutilized biological resources. We first performed genome-resolved metagenomics for AS taken from a municipal sewage treatment plant and obtained 97 nonribosomal peptide synthetase (NRPS)/polyketide synthase (PKS)-related gene sequences from 43 metagenomic assembled bins, most of which were assigned to the phyla Proteobacteria and Myxococcota. Furthermore, these NRPS/PKS-related genes are predicted to be novel because they were genetically dissimilar to known NRPS/PKS gene clusters. Of these, the condensation domain of the syringomycin-related NRPS gene cluster was detected in Rhodoferax- and Rhodocyclaceae-related bins, and its homolog was found in previously reported AS metagenomes as well as the genomes of three strains available from the microbial culture collections, implying their potential BCA ability. Then, we tested the antimicrobial activity of these strains against phytopathogenic fungi to investigate the potential ability of BCA by in vitro cultivation and successfully confirmed the actual antifungal activity of three strains harboring a possibly novel NRPS gene cluster. Our findings provide a possible strategy for discovering novel BCAs buried in the environment using genome-resolved metagenomics.

Sublethal effect of chlorpyrifos on predatory behavior and physiology of Eocanthecona furcellata (Hemiptera: Pentatomidae).

Insecticides have been known to reduce the predation efficacy of natural enemies. However, the mechanism of the sublethal effect of insecticides on the functional response of predators remains unclear. This study investigated the sublethal effects of the broad-spectrum insecticide chlorpyrifos on the predatory bug Eocanthecona furcellata (Wolff), which is a potential biological control agent against pests in integrated pest management (IPM) programs. After exposure to a sublethal concentration of chlorpyrifos, the predation capacity and the maximum predatory number of E. furcellata increased by 11.27 and 15.26%, respectively, with prey handling time decreased by 15.07%, and the searching efficiency increased by 5.88-12.61%. Additionally, the intraspecific interference effect was enhanced. Glutathione S-transferase (GST) activity was significantly decreased after 12- to 60-h treatment. At 12 h after treatment, the expression levels of GST gene (GST3), acetylcholinesterase gene (AChE), and cytochrome P450 monooxygenasegene (cyp6B1) were significantly up-regulated by 1.47-, 1.48-, and 2.05-fold, respectively, while GST gene (GST1) was significantly down-regulated by 16.67-fold. These results indicated that a sublethal chlorpyrifos concentration inhibited the GST activity and stimulated the predatory behavior of E. furcellata. The results will advance our understanding of the toxicological mechanism of predatory stink bug responses to insecticides and predict chlorpyrifos' effects on predators in an IPM program.

Biological control of weeds in Aotearoa / New Zealand: History, science and achievements to date

Aotearoa / New Zealand is the leading country globally in the use of biological control agents to combat introduced pest weed species. Here we review the history of biological control in Aotearoa / New Zealand, compile a list of current, self-introduced and accidentally introduced biocontrol agents, and list the agents currently under consideration for introduction to Aotearoa / New Zealand (accurate to 2021). We discuss the science and procedures in place for the safe introduction of a new biocontrol agent and discuss the public’s perception of biological control within Aotearoa / New Zealand. Since the 1920s there have been 79 control agents released; 68 of those species were deliberate introductions, eight self-introductions and three accidental introductions. Additionally, there have been eight reported occurrences of non-target-species attack by biological control agents in Aotearoa / New Zealand, all of which cause minor damage to their unintended hosts. Prior to their introduction to Aotearoa / New Zealand, potential biological control agents are required to undergo rigorous research and host-specificity testing to ensure that the agent does not pose a risk to indigenous taxa through non-target attack. This research is essential, as it ensures a precautionary approach is taken prior to introductions, which, in turn, provides the wider public with confidence in the validity of biocontrol agents as a means to manage weed species in Aotearoa / New Zealand.

Insecticidal Effect of the Entomopathogenic Fungus Lecanicillium araneicola HK-1 in Aphis craccivora (Hemiptera: Aphididae).

Aphis craccivora (Hemiptera: Aphididae) is an important pest affecting various crops worldwide. However, only few studies have been conducted on the infection of A. craccivora by Lecanicillium and related insecticidal mechanisms. We investigated the infection process of A. craccivora by Lecanicillium araneicola HK-1 using fluorescence microscopy and scanning electron microscopy (SEM), and our results indicated that the conidia of strain HK-1 easily attached to the feet and dorsum of A. craccivora. The activities of chitinase and extracellular protease were induced in the aphid after treatment with HK-1. A bioassay on A. craccivora showed that the median lethal concentration (LC50) of the fungus crude extract was 24.00 mg mL-1 for 24 h of treatment. Additionally, the results showed that the crude extract disrupted the enzyme system of A. craccivora, inducing the inhibition of carboxylesterase (CarE) and the induction of glutathione S-transferase (GST) and acetylcholinesterase (AChE). Combining these results with those of a gas chromatography-mass spectrometry (GC-MS) analysis, it is suggested that p-cymene, hymecromone, 9,12-octadecadienoic acid (Z, Z) methyl ester, and 9,12-octadecadienoic acid (Z, Z) may be connected to the insecticidal effects we observed. This study provides a theoretical basis for the use of L. araneicola HK-1 as a potential biological control agent.

Biological control of postharvest tomato fruit rots using Bacillus spp. and Pseudomonas spp.

BackgroundPostharvest diseases cause a wide loss to tomato fruits during handling and storing from harvest to consumers. Fungicides are mainly used to control postharvest diseases. Biological control is the eco-friendly substitute strategy used for postharvest diseases management as which becoming promise worldwide. Six bacterial bioagent (i.e., Bacillus subtilis, B. amyloliquefaciens, Pseudomonas resinovorans, P. alcaligenes, P. putida and P. stutzeri) were tested to suppress both Geotrichum candidum and Alternaria alternata causal agents of tomato fruit rots during storage.ResultsIn vitro, most of bioagents significantly reduced mycelial growth rate of G. candidum. Both of B. subtilis and P. stutzeri were the most superior bacterial bioagents with values 67.03 and 72.2%, respectively. In addition, B. subtilis and B. amyloliquefaciens resulted in the most superior over all antagonists against A. alternata. The lowest percent of disease incidence and severity of G. candidum were obtained by B. subtilis and P. stutzeri. The maximum reduction percent of it on tomato fruits was recorded by applying B. subtilis and P. stutzeri with values (90 and 87%) and (91, 89%) in both seasons, respectively. Also, the highest reduction of A. alternata was obtained by using B. subtilis, which resulted in 85 and 84% in both seasons, respectively. The application of bioagents against both pathogens was significantly improved fruit quality aspects (weight loss, vitamin C, TSS and acidity %) during storage period compared to infected control fruits.ConclusionThe findings revealed that both of B. subtilis and P. stutzeri could be potential biological control agents against most postharvest pathogens of tomato fruits. This might be an alternative control strategy instead of fungicides which service the sustainable and organic farming.

C-banding characterization of centric fusion and heterochromatin polymorphisms in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)

Abstract The water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae), shows a clinal variation for 3 Robertsonian translocation (centric fusion) polymorphisms in the southern extreme of its wide geographical distribution. It is a Neotropical semiaquatic grasshopper that lives, feeds, and lays eggs exclusively on floating plants of the family Pontederiaceae, or water-hyacinths, between 23° N (Southern Mexico) and 35° S (Central Argentina and Uruguay). Given the invasive-species status of Pontederia (formerly Eichhornia) crassipes and the voraciousness of these grasshoppers, they were considered as a potential biological control agent in addition to other natural enemies. We already described the association of the rearrangements with geographical and climatic variables, phenotypic variation, trivalent orientation, effects on recombination, and relationship with microsatellite variability. Here we analyze the distribution of constitutive heterochromatin in 2 populations of C. aquaticum in order to (i) provide consistent markers for a better distinction between all chromosomes, those which are involved in the centric fusions, and those which are not, and (ii) describe possible polymorphisms for C-positive supernumerary segments, given that, on conventional staining analysis, it was frequent to find heteromorphic autosomal bivalents. The cytogenetic analysis allowed us to get a detailed characterization of the constitutive heterochromatin distribution, providing unmistakable chromosome markers of the large, fusion-bearing chromosomes as well as the C-positive, polymorphic supernumerary segments.

Host-specificity of biocontrol agents in the field – The significance of sampling sympatric relatives of target weeds (Acacia holosericea versus A. auriculiformis)

Acacia auriculiformis is an invasive weed that causes significant environmental damage across Florida, USA. Previous native range surveys in Australia identified a number of herbivores that are commonly associated with this plant, including several species of leaf-tying moths (Macrobathra spp.) and a chrysomelid beetle (Calomela intemerata). These herbivores are considered strong candidates as biological control agents, but the range of host species they use has not been determined. We therefore conducted a transect survey of herbivorous insects on A. holosericea, a closely-related sympatric relative of A. auriculiformis. These species share areas of sympatry and the latter was sampled simultaneously (in sympatry and allopatry). DNA barcoding approach identified an array of herbivorous insects feeding on A. holosericea, but few were found on both the Acacia species sampled. A literature survey suggested this pattern of host specificity may be consistent across Australian acacias, to the extent that each Acacia species may largely host its own suite of herbivores. These results do not negate the need for host testing procedures in biological control, but they do increase our confidence substantially that several promising potential biological control agents of A. auriculiformis (Macrobathra moths and Calomela beetles) have a restricted host species range. Our study illustrates how exploring the herbivore diversity of plant species closely related to the target weed can provide crucial information for biological control researchers.

The transcriptome of the entomopathogenic fungus Culicinomyces clavisporus contains an ortholog of the insecticidal ribotoxin Hirsutellin.

The entomopathogenic fungus Culicinomyces clavisporus is known to infect and kill mosquito larvae and therefore has been seen as a potential biological control agent against disease vector mosquitoes. Whereas most fungal entomopathogens infect hosts by penetrating the external cuticle, C. clavisporus initiates infection through ingestion (per os). This unique infection strategy suggests that the C.clavisporus genome may be mined for novel pathogenicity factors with potential for vector control. To this end, an Isoseq-based transcriptome analysis was initiated, and resulted in a total of 3,512,145 sequences, with an average length of 1,732 bp. Transcripts assembly and annotation suggested that the C. clavisporus transcriptome lacked the cuticle-degrading proteins that have been associated with other entomopathogenic fungi, supporting the per os pathogenicity process. Furthermore, mining of the sequence data unexpectedly revealed C. clavisporus transcripts homologous to the Hirsutellin toxin. Comparative sequence analyses indicated that the C. clavisporus Hirsutellin predicted protein has retained the canonical molecular features that have been associated with the ribotoxic and insecticidal properties of the original toxin isolated from Hirsutella thompsonii. The identification of an Hirsutellin ortholog in C. clavisporus was supported by phylogenetic analyses demonstrating that Culicinomyces and Hirsutella were closely related genera in the Ophiocordycipitaceae family. Validation of the mosquitocidal activity of this novel C. clavisporus protein has yet to be performed but may help position Hirsutellin orthologs as prime candidates for the development of alternative biocontrol approaches complementing the current toolbox of vector mosquito management strategies.

First Parasitism Record of the Eggs of Thlastocoris laetus Mayr, 1866 (Hemiptera: Coreidae) and New Host and Distribution Records for Hadronotus vitripennis (Masner, 1983) (Hymenoptera: Scelionidae)

Thlastocoris laetus Mayr, 1866 (Hemiptera: Coreidae) is one of the main pineapple pests in the Amazon region. A survey of the natural enemies of T. laetus in pineapples of the BRS Turiaçu variety was conducted in Manaus and Itacoatiara, Amazonas state, Brazil, revealing a parasitism rate of 28.85% of T. laetus eggs by Hadronotus vitripennis (Masner, 1983) (Hymenoptera: Scelionidae). This is the first record of parasitism in T. laetus and of the occurrence of H. vitripennis in this host in Amazonas. This natural parasitism indicates that H. vitripennis is a potential biological control agent of the pineapple bug.

Occurrence of entomopathogenic fungi in coconut soils, identification, physiological characterisation and pathogenicity towards Rhynchophorus palmarum (Coleoptera: Dryophthoridae)

ABSTRACT Rhynchophorus palmarum is a significant pest of Cocos nucifera on the American continent. Therefore, this work aimed to search and characterise entomopathogenic fungi isolates to control R. palmarum under laboratory conditions. Sixty-three isolates of Metarhizium spp. were obtained from soil samples from different coconut plantations in four regions in Tabasco, México. The sites were edaphically characterised, and the presence of Metarhizium was almost null in the sites with 90% sand. The ITS region of the DNA of eleven isolates was analysed, and M. robertsii and M. anisopliae s.l. were identified. The mycelial growth (MG) of 38 isolates was evaluated, which were incubated at 25°C, 30°C, and ·35°C on Potato Dextrose Agar with Yeast for 14 d. The optimal growth for some strains was at 25°C and 30°C; for others, at 35°C. The MG colonies were small (< 1 cm) and irregular. The pathogenicity of the strains was evaluated in Tenebrio molitor larvae for 14 d with a conidia suspension 108 (conidia/mL). All the strains were pathogenic to T. molitor. However, only two strains (PAL 231.1, PAL 733.1) identified as M. robertsii reached cumulative mortality of over 60%. Then, these two strains were tested in adults of R. palmarum for 21 d with three conidia concentrations (107, 108, 109 conidia/mL). The suspension 109 conidia/mL of PAL 733.1 was the most pathogenic, with cumulative mortality of 60% and LT50 at 17 d. Therefore, the strain PAL 733.1 is proposed as a potential biological control agent against R. palmarum.

A New Species of Aleiodes Wesmael (Braconidae, Rogadinae) with Potential for Biological Control of Spodoptera spp. (Lepidoptera, Noctuidae), and Notes on the Definition of the gastritor, circumscriptus, and Related Species-Groups

A new species of Aleiodes Wesmael in the gastritor Thunberg species-group is described and illustrated. The new species, Aleiodes ceres Shimbori sp.n., occurs in Southern Brazil and Argentina. It is a potential biological control agent of caterpillars in the genus Spodoptera Guenée, namely S. cosmioides (Walker), S. eridania (Stoll), and S. frugiperda (J.E. Smith), which are serious pests on major crops including maize and soybean. The position of the new species within Aleiodes is discussed in relation to existing proposals of subdivisions of the genus into species-groups. In agreement with recent publications, the gastritor species-group is treated as separate from the circumscriptus Nees/bicolor Spinola group, as evidence suggests the latter is absent in the New World. We also propose the provisional shakirae Shimbori & Shaw species-group, to accommodate a clade of Neotropical species with geometrid hosts and morphological features similar to the gastritor and circumscriptus groups. A key to Neotropical species in the gastritor group and similar species is provided, except for species recently named without a morphological description.