Candidate For Biological Control Research Articles

Life history of Anastatus bifasciatus, a potential biological control agent of the brown marmorated stink bug in Europe

Anastatus bifasciatus (Geoffroy) is the most widespread native egg parasitoid of the invasive agricultural pest Halyomorpha halys (Stål) in Europe and considered as promising candidate for augmentative biological control. In this context, the parasitoid’s reproductive parameters, longevity, phenology, and temperature requirements for development were studied. In addition, the potential of using stored frozen H. halys eggs for mass production was investigated. In northwestern Switzerland, A. bifasciatus was able to complete three overlapping generations between June and October, which covers the entire oviposition period of its host. After an average pre-oviposition period of 11.9 days the mean potential lifetime fecundity of A. bifasciatus females was 52 eggs over an average oviposition period of 46 days. The number of H. halys eggs killed by either oviposition or host feeding was nearly the same. Females provided only with honey water lived on average 97.5 days. Development from egg to adult was possible from 15 °C to 32 °C, the lowest developmental time (15.9 days) being at 30 °C. Halyomorpha halys eggs of all ages yielded parasitoid offspring, but offspring emergence decreased with increasing age. Eggs stored up to 24 months at −80 °C were still suitable for parasitoid development. The wealth of information obtained on the life history of A. bifasciatus should be highly relevant to develop a release strategy of this parasitoid against its host, H. halys.

Insecticidal Activity of Photorhabdus luminescens against Drosophila suzukii.

Drosophila suzukii causes considerable economic damage to small and thin-skinned fruits including cherry, blueberry, raspberry, grape and strawberry. Since it attacks fruits at the ripening stage, the use of chemical pesticides is limited due to the high risk of residues on fruit. Biological control is thus expected to play an essential role in managing this pest. The Gram-negative bacterium, Photorhabdus luminescens and its symbiotic Heterorhabditis spp. nematode have been shown to be highly pathogenic to insects, with a potential for replacing pesticides to suppress several pests. Insecticidal activity of P. luminescens at different bacterial cell concentrations and its cell-free supernatant were assessed against third-instar larvae and pupae of D. suzukii under laboratory conditions. P. luminescens suspensions had a significant oral and contact toxicity on D. suzukii larvae and pupae, with mortalities up to of 70–100% 10 days after treatment. Cell-free supernatant in the diet also doubled mortality rates of feeding larvae. Our results suggest that P. luminescens may be a promising candidate for biological control of D. suzukii, and its use in integrated pest management (IPM) programs is discussed.

Toxic Peptides in Populations of Two Pergid Sawflies, Potential Biocontrol Agents of Brazilian Peppertree.

Determination of the safety of agents prior to release is one of the most important research goals in biological control. In addition to concerns for the safety of non-target plants, determination of the potential toxic properties of new agents needs to be assessed. Numerous phytophagous insects are defended by chemicals against the attack of natural enemies. Some of these defensive compounds could pose an environmental risk if an agent is released. Here, larval populations of two pergid sawflies, Heteroperreyia hubrichi and H. jorgenseni, were analyzed by LC-MS/MS to investigate whether they contain alleged toxic peptides. The first species is a potential candidate for biological control of the invasive weed Brazilian peppertree in Florida and Hawaii. The chemical analyses revealed the presence of the peptides pergidin (Perg), 4-valinepergidin (VPerg), dephosphorylated pergidin (dpPerg), lophyrotomin (LGln and LGlu). The effect of sawfly population for each species was significantly influencing peptide concentration. All peptides occurred at lower concentrations compared with purportedly toxic species of this sawfly family. However, the concentrations of the peptides are of concern for the welfare of wildlife and livestock that would be exposed to these species. These results demonstrate that release of this biological control agent in the invaded range may pose an environmental threat.

When taxonomy and biological control researchers unite: Species delimitation of Eadya parasitoids (Braconidae) and consequences for classical biological control of invasive paropsine pests of Eucalyptus

The invasive eucalyptus tortoise beetle, Paropsis charybdis, defoliates plantations of Eucalyptus nitens in New Zealand. Recent efforts to identify host specific biological control agents (parasitoids) from Tasmania, Australia, have focused on the larval parasitoid wasp, Eadya paropsidis (Braconidae), first described in 1978. In Tasmania, Eadya has been reared from Paropsisterna agricola (genus abbreviated Pst.), a smaller paropsine that feeds as a larva on juvenile rather than adult foliage of Eucalyptus nitens. To determine which of the many paropsine beetle hosts native to Tasmania are utilized by E. paropsidis, and to rule out the presence of cryptic species, a molecular phylogenetic approach was combined with host data from rearing experiments from multiple locations across six years. Sampling included 188 wasps and 94 beetles for molecular data alone. Two mitochondrial genes (COI and Cytb) and one nuclear gene (28S) were analyzed to assess the species limits in the parasitoid wasps. The mitochondrial genes were congruent in delimiting four separate phylogenetic species, all supported by morphological examinations of Eadya specimens collected throughout Tasmania. Eadya paropsidis was true to the type description, and was almost exclusively associated with P. tasmanica. A new cryptic species similar to E. paropsidis, Eadya sp. 3, was readily reared from Pst. agricola and P. charybdis from all sites and all years. Eadya sp. 3 represents the best candidate for biological control of P. charybdis and was determined as the species undergoing host range testing in New Zealand for its potential as a biological control agent. Another new species, Eadya sp. 1, was morphologically distinctive and attacked multiple hosts. The most common host was Pst. variicollis, but was also reared from Pst. nobilitata and Pst. selmani. Eadya sp. 1 may have potential for control against Pst. variicollis, a new incursion in New Zealand, and possibly Pst. selmani in Ireland. Our molecular data suggests that Pst. variicollis is in need of taxonomic revision and the geographic source of the beetle in New Zealand may not be Tasmania. Eadya sp. 2 was rarely collected and attacked P. aegrota elliotti and P. charybdis. Most species of Eadya present in Tasmania are not host specific to one beetle species alone, but demonstrate some host plasticity across the genera Paropsisterna and Paropsis. This study is an excellent example of collaborative phylogenetic and biological control research prior to the release of prospective biological control agents, and has important implications for the Eucalyptus industry worldwide.

Multiplex PCR Method for Discriminating Between Sphaerophoria macrogaster (Diptera: Syrphidae) and Sphaerophoria indiana (Diptera: Syrphidae)

Hoverflies are potential candidates for biological control of aphid populations; however, identification of closely related hoverfly species by using morphological characteristics is quite difficult. For instance, adults of Sphaerophoria macrogaster (Thomson) (Diptera: Syrphidae)-the predominant species early in the vegetable production season in Japan-are morphologically indistinguishable from those of Sphaerophoria indiana Bigot (Diptera: Syrphidae) without comparison of the male genitalia. Here, we investigated genetic variation of the mitochondrial cytochrome c oxidase subunit I (COI) gene of the two species by DNA sequencing and developed a multiplex PCR method for differentiating the two species. Alignment of COI sequences revealed 1.2% nucleotide variance between the two species. The COI sequence of S. macrogaster collected from Japan was 99.8% identical to those of S. macrogaster collected from India. The COI sequence of S. indiana collected from Japan was 100% identical to that of Sphaerophoria philanthus (Meigen) (Diptera: Syrphidae) collected from Canada. The sizes of the multiplex PCR products differentiated following gel electrophoresis were 162 bp for S. macrogaster and 607 bp for S. macrogaster and S. indiana. The accuracy rate of multiple PCR was 100%. Use of this method will facilitate further research into the characteristics of hoverflies and will improve the efficacy of biological control using hoverflies on vegetable crops.

In Vitro Suppressive Effect of Agriculture Residues and Municipal Solid Wastes Compost Tea on some Phytopathogenic Fungi

Aerated Compost Tea (ACT) prepared from four types of compost; Agricultural Residues(AR), Agricultural Residues enriched with Olive Pomace (AR+OP), Municipal Solid Wastes (MSW) and Municipal Solid Wastes enriched with OP(MSW+OP) in combination with bioagents have been analytically characterized and were tested for their antagonistic activity in vitro against Fusarium oxysporum and Rhizoctonia solani pathogens in comparison with the commercial chemical fungicides (Rhizolex-T). Assessment was carried out in terms of percent mycelial growth inhibition as well as Scanning Electron Microscopy (SEM) were used to explain the mode of action in the biological control of the pathogens under study. From the resultsall compost teas showed high levels of nutrients and microbial biomass content. The mixed treatment of compost tea gave the highest percent inhibition compared with individually treatments. AR compost tea+ Olive Pomace (OP)+ Microorganisms (MO) were significantly superior to the rest treatments showed 63.52% and 44.07% percent inhibition, same trend was detected with MSW+ Olive Pomace (OP)+ Microorganisms (MO) showing 57.41% and 43.89% against Rhizoctonia solani andFusarium oxysporumrespectively. SEM of tested pathogen mycelium removed from the confrontation zone showed aberrant morphology such as shrinkage, curling,mycelium asymmetry, partial distortions and lysis of fungal mycelium. In conclusion, these results provide evidence that the compost extract has the potential to become a good candidate for biological control as potential alternatives to the application of synthetic fungicides, and as plant promoters in crop production, for attaining environmental sustainability for farming and food safety.

Molecular comparisons of native range collections of Gadirtha fusca, a potential biological control agent of Chinese tallowtree

ABSTRACTChinese tallowtree, Triadica sebifera (L.) Small (Euphorbiaceae), is one of the worst invasive weeds of the southeastern USA impacting coastal wetlands, forests, and natural areas. A proposed biological control candidate, the defoliating moth Gadirtha fusca Pogue (Lepidoptera: Nolidae) shows high specificity for the target weed Chinese tallowtree. A total of 13 field sites were sampled in the native range of this herbivore species. To determine if all individuals were the same taxon, molecular DNA analyses were conducted of these collections. These included collections from 2012, 2015 and 2016, from three regions and two adult color morphs. Molecular COI analysis was performed on thirty colonized individuals from these collections. The results of this analysis arranged all taxa into a single clade with average genetic divergence values of 0.3%. Comparison of these G. fusca sequences and those from other Gadirtha spp. all had divergence values that were equal to or exceeded 5%. These results indicate that all the G. fusca collections were a single species and they were distinct from other known members of this genus.

Updated list of the insect parasitoids (Insecta, Hymenoptera) associated with Lobesia botrana (Denis & Schiffermüller, 1775) (Lepidoptera, Tortricidae) in Italy. 2. Hymenoptera, Ichneumonidae, Anomaloninae and Campopleginae.

In this second review of the parasitoids recorded on Lobesia botrana (EGVM) in Italy, an updated list and summary of the information available on 14 taxa of Ichneumonidae belonging to the subfamilies Anomaloninae and Campopleginae are provided. For each taxon, geographic distributions, host ranges, ecological role in viticulture and/or in other crops, and taxonomy are provided and discussed. For the most interesting species, tables summarizing the parasitization rates recorded in the field on EGVM or other lepidopteran pests are given. Identification mistakes and wrong synonymies that have generated great confusion and often made geographic distributions and host ranges unreliable are highlighted. A list of four Anomaloninae and 27 Campopleginae recorded on EGVM in Europe is also provided. Among the species examined, Campoplex capitator Aubert is the only potential candidate for biological control of EGVM.

A review of known parasitoids of hemlock looper (Lepidoptera: Geometridae) in Canada and first records of egg and larval parasitoids in Labrador forests

AbstractA rearing study of egg and larval parasitoids of hemlock looper (Lambdina fiscellaria (Guenée); Lepidoptera: Geometridae) was undertaken during an outbreak of this pest in Labrador, Newfoundland and Labrador, Canada. Six parasitoid species were found: Telenomus coloradensis Crawford and T. droozi Muesebeck (Hymenoptera: Platygastridae), Winthemia occidentis Reinhard and Blondelia eufitchiae (Townsend) (Diptera: Tachinidae), as well as one species of Phobocampe Förster and Mesochorus vittator (Zetterstedt) (Hymenoptera: Ichneumonidae). None of them was a new Canadian record. To facilitate understanding of the regional parasitoid assemblage in Labrador, we compiled all published records in Canada and collated all specimen records from the Canadian National Collection of Insects, Arachnids, and Nematodes (Ottawa, Ontario, Canada). This comprehensive list will aid researchers interested in potential biological control candidates for hemlock looper.

Swirski Mite Controlled-release Sachets as a Pest Management Tool in Container Tree Production

Adoption of biological control tools in woody ornamental nursery production has lagged behind other agriculture fields. One of the major obstacles to adoption is lack of information on the efficacy of various biological control agents in nursery production systems. The predatory mite Amblyseius swirskii, sold commercially as “swirski mite,” is a generalist predatory mite that has recently been adopted as a generalist control for a wide range of mite and insect pests, including thrips (Thripidae), whiteflies (Aleyrodidae), eriophyid mites (Eriophyidae), broad mite (Polyphagotarsonemus latus), and spider mites (Tetranychidae). A controlled-release sachet formulation of swirski mite was evaluated in three experiments to determine whether size of the tree, timing of first application, or sun intensity would affect treatment efficacy. Pest numbers on plants was evaluated biweekly for 12 weeks. The swirski mite sachets controlled broad mite and spider mite outbreaks on red maple trees (Acer rubrum) grown in nos. 3 and 15 nursery containers, respectively. Application at the time of red maple rooted cutting transplant was not necessary to achieve summer-long control of pests. No outbreaks of target pests on flowering dogwood (Cornus florida) in no. 5 containers grown under both full sun and shade, but with low levels of broad mite persisting in the shade treatment and thrips persisting in sun. These results suggest that swirski mite is a promising candidate for biological control in woody ornamental nursery production.

Taxonomy, bionomics and predatory potential of Eocanthecona concinna (Walker) (Hemiptera: Pentatomidae: Asopinae)

Eocantheocna concinna (Walker) is recorded as an important predator of lepidopteran pests in tea plantations of South India. It is described for the first time based on male and female genitalia. Biology of this predator was studied on Corcyra cephalonica larvae. Egg incubation period was 14.3 ± 0.4 days. Five nymphal instars were developed in a period of 33–36 days. Feeding efficacy of different instars of E. concinna was evaluated on third instar tea looper, Biston suppressaria . Results showed fourth and fifth instars of E. concinna attacked faster on B. suppressaria . The study describes E. concinna as a potential predator of various lepidopteran pests in tea plantations and a promising candidate for biological control of looper pests.

Effect of Aspergillus flavus on the mortality and activity of antioxidant enzymes of Spodoptera litura Fab. (Lepidoptera: Noctuidae) larvae

Insects have developed tolerance against mycoses caused by entomopathogenic fungi through several humoral and cellular mechanisms. Antioxidant enzymes such as superoxide dismutase, lipid peroxidase, and peroxidase can play a role in defense against mycosis, but the physiological interactions between the fungus and the insect are not well characterized. In this study, the effects of infection by entomopathogenic fungus, Aspergillus flavus on the antioxidant defense system of Spodoptera litura, were investigated. The fungi, A. flavus exposure resulted in modification of the levels of antioxidant enzymes, as well as significant decline in phenoloxidase titers and the total hemocyte count 48 h post exposure. A significant increase was observed in detoxifying enzymes. All these results suggest that A. flavus infects S. litura by directly acting on the immune system, resulting in decreased immune function. Bioassay results showed that A. flavus affects third and fourth instar larvae of S. litura. This report supports the importance of A. flavus as a candidate for biological control of S. litura.

Food web associations and effect of trophic resources and environmental factors on parasitoids expanding their host range into non‐native hosts

AbstractTrophic interactions and environmental conditions determine the structure of food webs and the host expansion of parasitoids into novel insect hosts. In this study, we investigate plant–insect–parasitoid food web interactions, specifically the effect of trophic resources and environmental factors on the presence of the parasitoids expanding their host range after the invasion of Chrysodeixis chalcites (Esper) (Lepidoptera: Noctuidae). We also consider potential candidates for biological control of this non‐native pest. A survey of larval stages of Plusiinae (Lepidoptera: Noctuidae) and their larval parasitoids was conducted in field and vegetable greenhouse crops in 2009 and 2010 in various locations of Essex and Chatham‐Kent counties in Ontario, Canada. Twenty‐one plant–host insect–host parasitoid associations were observed among Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), C. chalcites, and larval parasitoids in three trophic levels of interaction. Chrysodeixis chalcites, an old‐world species that had just arrived in the region, was the most common in our samples. The larval parasitoids Campoletis sonorensis (Cameron) (Hymenoptera: Ichneumonidae), Cotesia vanessae (Reinhard), Cotesia sp., Microplitis alaskensis (Ashmead), and Meteorus rubens (Nees) (all Hymenoptera: Braconidae) expanded their host range into C. chalcites changing the structure of the food web. Copidosoma floridanum (Ashmead) (Hymenoptera: Encyrtidae) was the most common parasitoid of T. ni that was not found in the invasive species. Plant species, host abundance, and agro‐ecosystem were the most common predictors for the presence of the parasitoids expanding their host range into C. chalcites. Our results indicate that C. sonorensis, C. vanessae, and C. floridanum should be evaluated for their potential use in biological control of C. chalcites and T. ni.

The effect of strawberry cultivars, infested with Tetranychus urticae (Acari: Tetranychidae), on the olfactory response of the predatory mite Neoseiulus californicus (Acari: Phytoseiidae)

Tetranychus urticae Koch (Acari: Tetranychidae) is a key pest of agricultural crop. One of the best candidates for biological control of this mite is Neoseiulus californicus (McGregor) (Acari: Phytoseiidae). In this study, the olfactory response of the predatory mite to seven strawberry cultivars (‘Marak’, ‘Yalova’, ‘Aliso’, ‘Gaviota’, ‘Sequoia’, ‘Camarosa’ and ‘Chandler’) was studied using a Y-tube olfactometer. We used two-day-old female predatory mites that were reared on spider mite-infested strawberry. The behavioral response of the predator was studied in four experiments: 1) clean air vs. uninfected strawberry plant, 2) clean air vs. spider mite-infested strawberry plant, 3) uninfected strawberry plant vs. spider mite-infested strawberry plant and 4) two-cultivar choice test (spider mite-infested). In the first experiment, the attraction of the predatory mite to uninfected strawberry plant volatiles was significant. In the second test, the predators significantly preferred volatiles from strawberry plant infested with T. urticae to clean air. In the third test, 68% to 80% of the predatory mites were attracted to spider mite-infested strawberry plant volatiles compared with uninfected plants. Among the seven strawberry cultivars, the predator responses to volatiles of infested plants varied 62% to 83% and to volatiles of uninfested plant varied 59% to 75%. Herbivore – induced plant volatile emitted from strawberry infested with T. urticae attract the predatory mite. The last test showed that ‘Aliso’ and ‘Chandler’ were more attractive for the predatory mite.

DNA sequencing to help identify crop pests and their natural enemies in agro-ecosystems: The case of the millet head miner Heliocheilus albipunctella (Lepidoptera: Noctuidae) in sub-Saharan Africa

Better knowledge of natural enemy communities and their relative contribution to biological control is needed to design ecology-based pest management in agro-ecosystems. Here, we investigated the arthropod communities of pearl millet-based agro-ecosystems in sub-Saharan Africa (Senegal), with a focus on natural enemies of the millet head miner (MHM), Heliocheilus albipunctella (de Joannis).A set of 105 millet fields was monitored over the 2014–2016 growing seasons. Arthropods were sampled at three successive phenological stages, from panicle emergence to grain maturity. Eggs and larvae from Lepidoptera pests were collected to assess their identity and relative contribution to the biological control of parasitoids. Morphological identification combined with Sanger and Illumina DNA sequencing, using the COI full barcode (658 bp) and the COI mini-barcode (133 bp) respectively, was carried out to characterize arthropod samples.MHM was by far the main herbivore on millet, with a relative abundance of 97%. Predators were mostly ants (28%), earwigs (Forficula senegalensis, 26%), mirids (20%), spiders (12%), carabid larvae (7%), flower bugs (Orius maxidentex, 6%), and ladybirds (Declivitata hamata, 1%). In all, 13 primary parasitoid species were collected, including five new species. Parasitism was dominated by three key species, including Trichogrammatoidea armigera (12.4% of egg parasitism), Copidosoma primulum and Schoelandella spp. (46 and 32% of larval parasitism, respectively). A primary reference database including standard and mini-barcode sequences of specimens attributed to species (15) was designed as a reliable tool for assisting arthropod identification. The results will be helpful when selecting candidates for augmentative biological control in millet-based agro-ecosystems in sub-Saharan Africa.

A review of open-field host range testing to evaluate non-target use by herbivorous biological control candidates

One of the fundamental challenges of pre-release studies in classical biological weed control is to assess and predict the likelihood and consequences of non-target effects. Unless a candidate biological control agent is proven to be monophagous through conventional starvation and host-specificity tests in quarantine, open-field host range studies can be important in predicting the likelihood of non-target effects since they reveal the host selection of herbivores displaying the whole array of pre- and post-alightment behaviours. Over the course of its 53-year history, the purpose and the design of open-field host range studies have changed considerably, with more recent studies clarifying or refining specific questions related to one or a few test plant species and using a set design. We discuss the opportunities and challenges of this approach and suggest that future open-field host range studies should be more hypothesis-driven and apply different experimental designs that facilitate the interpretation of the results.

Genotype assembly, biological activity and adaptation of spatially separated isolates of Spodoptera litura nucleopolyhedrovirus.

The cotton leafworm Spodoptera litura is a polyphagous insect. It has recently made a comeback as a primary insect pest of cotton in Pakistan due to reductions in pesticide use on the advent of genetically modified cotton, resistant to Helicoverpa armigera. Spodoptera litura nucleopolyhedrovirus (SpltNPV) infects S. litura and is recognized as a potential candidate to control this insect. Twenty-two NPV isolates were collected from S. litura from different agro-ecological zones (with collection sites up to 600 km apart) and cropping systems in Pakistan to see whether there is spatial dispersal and adaptation of the virus and/or adaptation to crops. Therefore, the genetic make-up and biological activity of these isolates was measured. Among the SpltNPV isolates tested for speed of kill in 3rd instar larvae of S. litura, TAX1, SFD1, SFD2 and GRW1 were significantly faster killing isolates than other Pakistani isolates. Restriction fragment length analysis of the DNA showed that the Pakistan SpltNPV isolates are all variants of a single SpltNPV biotype. The isolates could be grouped into three genogroups (A-C). The speed of kill of genogroup A viruses was higher than in group C according to a Cox' proportional hazards analysis. Sequence analysis showed that the Pakistan SpltNPV isolates are more closely related to each other than to the SpltNPV type species G2 (Pang et al., 2001). This suggests a single introduction of SpltNPV into Pakistan. The SpltNPV-PAK isolates are distinct from Spodoptera littoralis nucleopolyhedrovirus. There was a strong correlation between geographic spread and the genetic variation of SpltNPV, and a marginally significant correlation between the latter and the cropping system. The faster killing isolates may be good candidates for biological control of S. litura in Pakistan.

Ecological applications of Pseudomonas as a biopesticide to control two-spotted mite Tetranychus urticae: chitinase and HCN production

Abstract The two-spotted spider mite (Tetranychus urticae Koch) is an important pest of many horticultural crops. A study was conducted to evaluate the effect of three fluorescent Pseudomonas isolates obtained from rhizospheric soil of tomato (Solanum lycopersicon) in Agadir, Morocco: Q110B, Q036B and Q172B, as potential biological control agents for T. urticae. Both acaricide and repellent activities were assessed on homogenous adult mites. The acaricidal activity test evaluated five concentrations of bacterial suspensions: 0 (control), 102, 104, 106, 108, and 1010 cfu · ml−1, while only the 1010 cfu ∙ ml−1 concentration of each bacterium was used for the repellent bioassay. The mortality rate and repellentindex were recorded 24, 48 and 72 h after application. Results indicated that the survival rate of T. urticae was reduced (p ≤ 0.01) by all three bacterial isolates compared to control. Within the 24–72 h time period the mortality rates ranged from 8 to 87%, 16 to 99%, and 13 to 89%, for Q110B, Q036B and Q172B isolates, respectively. The isolate Q036B (LC50 = 0.598 cfu · ml−1) provided higher mortality rates than Q172B and Q110B with LC50 values of 90,846 and 169,585 cfu · ml−1, respectively. Repellent activity was also the highest with Pseudomonas Q036B having a 71% repellence index at 48 h after application. Regarding the mechanism of action, all three isolates produced hydrogen cyanide, and exhibited protease and cellulose activities, although only Q036B and Q172B had potential chitinase action. Identification analysis showed that the isolates were either Pseudomonas putida (Q172B) or P. fluorescens (Q110B and Q036B). Our results indicate that the P. fluorescens isolate Q036B is a promising candidate for biological control of T. urticae, and has potential to contribute to an integrated pest management program to control this important pest. Then the fruits produced will be qualified as safe for consumers and the environment. The present work was customized to give support for policy decision makers as an agroecological potential meeting needs of industries and ecological balance.

Examining olfactory and visual cues governing host-specificity of a weed biological control candidate species to refine pre-release risk assessment

In weed biological control programs, pre-release host-specificity testing relies traditionally on no-choice and choice feeding, oviposition, and development tests. Rarely have they included detailed examination of behavioral responses to olfactory and visual cues of biological control candidates, although a better understanding of the mechanisms underlying host recognition may explain potential discrepancies between choice and no-choice tests, and/or between tests conducted in the lab versus field conditions. We investigated how the seed-feeding weevil, Mogulones borraginis, distinguishes its host plant, Cynoglossum officinale, from three native confamilial non-target species in North America. In behavioral bioassays, M. borraginis responded to olfactory and visual cues individually and, to an even greater extent, to both plant cue modalities when offered simultaneously. In tests with the combined cues, M. borraginis was attracted to C. officinale but responded with indifference or was repelled by non-target plants. In electrophysiological experiments, we identified that M. borraginis responded to ten volatile compounds and four wavelengths of lights from inflorescences of C. officinale. We propose that studies of responses to multimodal plant cues can advance our understanding of how biocontrol candidate species discriminate among host plants and closely related non-target species, thereby increasing the accuracy of environmental safety assessments pre-release.

Reciprocal intraguild predation between Neoseiulus barkeri and Amblyseius swirskii (Mesostigmata: Phytoseiidae): Does experience affect anti-intraguild predation behaviors?

In order to increase their inclusive fitness, animals predominantly probe their changing environment for predation cues to adopt appropriate antipredator strategies and decrease the costs of defensive behavior. Intraguild predation (IGP) occurs when a predator kills and consumes individuals of another predator which is its competitor for a shared prey. IGP is prevalent among predatory mites of the family Phytoseiidae which are used as biological control agents of agricultural pests worldwide. Phytoseiid mite mothers usually display antipredator behaviors to avoid or reduce IGP risk of their juveniles. When facing a novel IGP risk, experience may enable the mothers to display more efficient antipredator responses. We studied the effect of experience on reciprocal antipredator behaviors of an indigenous predatory phytoseiid mite, i.e., Neoseiulus barkeri Hughes, and an exotic one, i.e., Amblyseius swirskii Athias-Henriot, as biological control candidates for integrated pest management strategies in Iran. First, we determined the occurrence of IGP and mutual risk of the predators within the guild; IGP occurred reciprocally and A. swirskii was the stronger IG predator. Second, in choice situations between a patch with only shared prey and a patch with shared prey plus IGP risk cues, we scrutinized patch choice, oviposition site selection and ability to counterattack by females of each species that had either experienced the IGP risk or not. The experience did not affect patch choice and oviposition behaviors of the species whereas it elicited an increase in their predation on IG predator juveniles. We suggest that the presence of IG predator juveniles and cues may not significantly modify the distribution of the IG prey species. The reinforced counterattack behavior in experienced females showed that both species were able to tune their antipredator behavior after exposure to IG predators. Consequences of the antipredator behaviors in experienced IG prey females on distribution and possibilities of the coexistence of the study species are discussed.