International Organization For Biological Control Research Articles

Lethal and sublethal effects of insecticides used in cotton crop on the mealybug endoparasitoid Aenasius arizonensis

Lethal effects of eight insecticides at field dosages recommended in cotton crop were assessed against Aenasius arizonensis (Girault) (Hymenoptera: Encyrtidae), a key endoparasitoid of the mealybug Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae). Based on adult mortality, spiromesifen, buprofezin and flonicamid were categorized as slightly harmful, whereas, profenophos, sulfoxaflor, diafenthiuron, imidacloprid and thiodicarb were categorized as harmful insecticides according to the classification proposed by International Organization for Biological Control (IOBC). On exposure of mummies to insecticides, spiromesifen, buprofezin and flonicamid were categorized as harmless, whereas, profenophos and sulfoxaflor were highly toxic on the basis of reduction in adult emergence. Afterward, adults of A. arizonensis emerged from mummies exposed to four insecticides (spiromesifen, flonicamid, buprofezin and imidacloprid) were evaluated for sublethal effects in the subsequent generation. Spiromesifen and flonicamid caused the lowest reduction in parasitism rate of the parasitoid (harmless), while imidacloprid and buprofezin the most (slightly harmful). Imidacloprid significantly prolonged the development time and also reduced the longevity of A. arizonensis. However, buprofezin had no effect on development time of the parasitoid. All these four insecticides did not have any negative effect on the sex-ratio of A. arizonensis. Buprofezin, spiromesifen and flonicamid could facilitate biologically-based integrated pest management programs in cotton agroecosystem

Lethal and sublethal effects of ten insecticides, used in date palm production in Saudi Arabia, on the parasitoid Trichogramma cacoeciae

Abstract Lethal and sublethal effects of ten insecticides commonly used in date palm production in Saudi Arabia were assessed in the laboratory against adults of Trichogramma cacoeciae, an important egg parasitoid of the dried fruit moth Ephestia calidella. Bioassays were conducted according to the standard protocol of the International Organization for Biological Control IOBC/WPRS/Working Group ‘Pesticides and Beneficial Organisms’. Our results showed that cypermethrin, deltamethrin, malathion, phenthoate, methomyl, and carbosulfan were moderately harmful (IOBC Class 3) to the parasitoid. The botanical insecticides azadirachtin and matrine were moderately harmful (IOBC Class 3) and slightly harmful (IOBC Class 2), respectively. The insect growth regulator pyriproxyfen was slightly harmful, whereas bistrifluron was harmless (IOBC Class 1). Regarding sublethal effects, the parasitism ratios compared to control were reduced by pyriproxyfen and azadirachtin to 49.0% and 58.0%, respectively; hence they are classified as slightly harmful insecticides (IOBC Class 2). Bistrifluron and matrine were harmless (IOBC Class 1) as parasitism ratios were reduced by 9.2% and 27.6%, respectively. Longevity of adults exposed to bistrifluron and matrine (3.6 and 3.3 days, respectively) and to pyriproxyfen and azadirachtin (1.7 and 1.3 days, respectively) was significantly lower than that in control (4.67 days). In semi-field tests, residues of most insecticides on leaves of tomato, a common host plant of lepidopteran pests parasitized by T. cacoeciae, were considered moderately harmful to harmful based on parasitoid mortality at 24 h post-treatment whereas they were slightly harmful at 7 and 14 days post-treatment

Selectivity of different biological products to the egg parasitoid Telenomus remus (Hymenoptera: Platygastridae)

The selectivity of five entomopathogens and a chemical insecticide (positive control) to pupae and adults of the egg parasitoid Telenomus remus (Nixon) was evaluated in the laboratory under controlled environmental conditions according to protocols established by the International Organization for Biological Control. Baculovirus anticarsia (Baculovirus AEE®), Bacillus thuringiensis var. kurstaki (Thuricide®), Bacillus thuringiensis var. aizawai (Agree®), Beauveria bassiana (Boveril®), Metarhizium anisopliae (Metarril®) and Trichoderma harzianum (Trichodermil®) are harmless to T. remus pupae, and adults. Thus, our results suggest that the insect control strategies applied here are compatible since entomopathogens were classified as harmless to T. remus in most examined cases and therefore facilitate a joint application to control different pests. Bacillus thuringiensis var. kurstaki (Dipel®), despite being classified as slightly harmful in some of the evaluations, can still be considered compatible for use together with T. remus, especially when compared with chemical insecticides such as chlorpyrifos that might be considered harmful to the parasitoid survival.

Physiological susceptibility of the predator Macrolophus basicornis (Hemiptera: Miridae) to pesticides used to control of Tuta absoluta (Lepidoptera: Gelechiidae)

ABSTRACTIn order to aid the integration of biological and chemical controls for the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), this study evaluated the relative toxicity of five insecticides to the leaf miner predator Macrolophus basicornis (Stal) (Hemiptera: Miridae). The insecticides evaluated were teflubenzuron, abamectin, chlorantraniliprole, chlorfenapyr, and cartap hydrochloride, all of which are recommended for control of T. absoluta in Brazil. Nymphs and adults of M. basicornis were exposed to tomato leaves treated with the insecticides, under laboratory and greenhouse conditions. The overall mortality caused by the products in both situations was recorded, and the survival of congeneric groups was analysed using the Weibull model. The persistence of the insecticides was also evaluated and they were categorised into toxicity classes proposed by the International Organisation for Biological Control (IOBC) based on predator mortality and persistence. Abamectin and chlorfenapyr were toxic to M. basicornis nymphs and adults in all bioassays. Cartap hydrochloride was slightly harmful to adults in laboratory assays, but harmful to nymphs, and moderately harmful under greenhouse conditions. Chlorantraniliprole and teflubenzuron were harmless in most assays, except when nymphs were exposed in the laboratory, where they were moderately and slightly harmful, respectively. Chlorantraniliprole and teflubenzuron should be preferred insecticides for use in tomato leaf miner IPM programmes that aim to conserve M. basicornis populations.

The status of biological control and recommendations for improving uptake for the future

Classical and augmentative biological control of insect pests and weeds has enjoyed a long history of successes. However, biocontrol practices have not been as universally accepted or optimally utilised as they could be. An International Organisation for Biological Control (IOBC) initiative brought together practitioners and researchers from widely diverse fields to identify the main limitations to biocontrol uptake and to recommend means of mitigation. Limitations to uptake included: risk averse and unwieldy regulatory processes; increasingly bureaucratic barriers to access to biocontrol agents; insufficient engagement and communication with the public, stakeholders, growers and politicians of the considerable economic benefits of biocontrol; and fragmentation of biocontrol sub-disciplines. In this contribution we summarise a range of recommendations for the future that emphasise the need for improved communication of economic, environmental and social successes and benefits of biological control for insect pests, weeds and plant diseases, targeting political, regulatory, grower/land manager and other stakeholder interests. Political initiatives in some countries which augur well for biocontrol in the future are discussed.

Explanation of the Nagoya Protocol on Access and Benefit Sharing and its implication for microbiology.

Working with genetic resources and associated data requires greater attention since the Nagoya Protocol on Access and Benefit Sharing (ABS) came into force in October 2014. Biologists must ensure that they have legal clarity in how they can and cannot use the genetic resources on which they carry out research. Not only must they work within the spirit in the Convention on Biological Diversity (https://www.cbd.int/convention/articles/default.shtml?a=cbd-02) but also they may have regulatory requirements to meet. Although the Nagoya Protocol was negotiated and agreed globally, it is the responsibility of each country that ratifies it to introduce their individual implementing procedures and practices. Many countries in Europe, such as the UK, have chosen not to put access controls in place at this time, but others already have laws enacted providing ABS measures under the Convention on Biological Diversity or specifically to implement the Nagoya Protocol. Access legislation is in place in many countries and information on this can be found at the ABS Clearing House (https://absch.cbd.int/). For example, Brazil, although not a Party to the Nagoya Protocol at the time of writing, has Law 13.123 which entered into force on 17 November 2015, regulated by Decree 8.772 which was published on 11 May 2016. In this case, export of Brazilian genetic resources is not allowed unless the collector is registered in the National System for Genetic Heritage and Associated Traditional Knowledge Management (SisGen). The process entails that a foreign scientist must first of all be registered working with someone in Brazil and have authorization to collect. The enactment of European Union Regulation po. 511/2014 implements Nagoya Protocol elements that govern compliance measures for users and offers the opportunity to demonstrate due diligence in sourcing their organisms by selecting from holdings of 'registered collections'. The UK has introduced a Statutory Instrument that puts in place enforcement measures within the UK to implement this European Union Regulation; this is regulated by Regulatory Delivery, Department for Business, Energy and Industrial Strategies. Scientific communities, including the private sector, individual institutions and organizations, have begun to design policy and best practices for compliance. Microbiologists and culture collections alike need to be aware of the legislation of the source country of the materials they use and put in place best practices for compliance; such best practice has been drafted by the Microbial Resource Research Infrastructure, and other research communities such as the Consortium of European Taxonomic Facilities, the Global Genome Biodiversity Network and the International Organisation for Biological Control have published best practice and/or codes of conduct to ensure legitimate exchange and use of genetic resources.

Compatibility of sulfoxaflor and other modern pesticides with adults of the predatory mite Amblyseius swirskii. Residual contact and persistence studies

Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) is a very efficient generalist predatory mite of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), worldwide released in horticultural greenhouses. Here, the toxicity of sulfoxaflor and other ten pesticides to A. swirskii adults when applied at their maximum field rate was assessed in the laboratory in terms of mortality and reproductive performance. The duration of the harmful activity when residues were aged under greenhouse was assessed for compounds not classified as harmless in the laboratory, based on the International Organization for Biological Control (IOBC) rules. Sulfoxaflor as well as flonicamid, flubendiamide, metaflumizone, methoxyfenozide, spiromesifen, and spirotetramat were harmless, emamectin was slightly harmful and abamectin, deltamethrin and spinosad were harmful. Emamectin was short-lived and abamectin, deltamethrin and spinosad were slightly persistent under our conditions.

Can toxicants used against cotton mealybug Phenacoccus solenopsis be compatible with an encyrtid parasitoid Aenasius bambawalei under laboratory conditions?

The cotton mealybug, Phenacoccus solenopsis Tinsley (Sternorrhyncha: Pseudococcidae) is a serious pest of various cultivated plants in Pakistan. Recent reports show that the parasitoid Aenasius bambawalei Hayat (Hymenoptera: Encyrtidae) is a good biocontrol agent of the pest. Compatibleness is important in any IPM programme, and the insecticide used must have little or no effects on the biological control agent. This study investigated the compatibility of neem treatments and a commercial insecticide, imidacloprid on A. bambawalei. Bioassays were laid out in a completely randomized design (CRD) under laboratory conditions. Results showed that the adult stage of the parasitoid was more susceptible to the commercial insecticide imidacloprid than the concealed pupal stage. Moreover, on the basis of the International Organization for Biological Control (IOBC) toxicity categories of the commercial insecticide, imidacloprid was moderately toxic throughout the study period (Ex >80%) while neem was slightly toxic after 24h of use (Ex <80%). Results also suggest that A. bambawalei release should be delayed for at least 1week after neem treatments. Because imidacloprid destroys A. bambawalei, it might cause resurgence of P. solenopsis; thus, farmers should avoid integrating the insecticide in the control of P. solenopsis.

Selectivity of plant extracts for Trichogramma pretiosum Riley (Hym.: Trichogrammatidae)

We evaluated the selectivity of three plant extracts with potential insecticidal effects for the parasitoid Trichogramma pretiosum Riley, which is commonly used in biological pest control. The plant extracts assayed were an acetone extract of Toona ciliata M. Roem., commercial neem oil, and a nanoencapsulated formulation of neem oil (NC40). The toxicity of the plant extracts to T. pretiosum was evaluated according to the recommendations of the International Organization for Biological Control- IOBC Working Group. We assessed the susceptibility of adults of the maternal and F1 generations and immature stages of T. pretiosum to the extracts. Females exposed to egg cards treated with commercial neem oil parasitized almost 70% fewer eggs than control eggs treated with water; and this extract was therefore classified as slightly harmful. When the eggs were offered to females 24h after treatment with neem oil and aqueous NC40, the parasitism rate also decreased, and the two extracts were classified as slightly harmful. Adult emergence was lower for parasitoids that fed on host eggs offered 24h after the treatment with the T. ciliata extract, which was considered slightly harmful. The emergence of T. pretiosum from eggs, larvae and pupae treated with the different plant extracts, did not decrease compared to development stages treated with the water control. The use of T. pretiosum, combined with the application of an ethanol extract of T. ciliata and a nanoencapsulated formulation of neem, appears to be feasible in view of these low toxicity indices.

Herbicide toxicity, selectivity and hormesis of nicosulfuron on 10 Trichogrammatidae (Hymenoptera) species parasitizing Anagasta ( = Ephestia) kuehniella (Lepidoptera: Pyralidae) eggs

ABSTRACTSelective agrochemicals including herbicides that do not affect non-target organisms such as natural enemies are important in the integrated pest management (IPM) programs. The aim of this study was to evaluate the herbicide toxicity, selectivity and hormesis of nicosulfuron, recommended for the corn Zea mays L. (Poaceae) crop, on 10 Trichogrammatidae (Hymenoptera) species. A female of each Trichogramma spp. or Trichogrammatoidea annulata De Santis, 1972 was individually placed in plastic test tubes (no choice) with a cardboard containing 45 flour moth Anagasta ( = Ephestia) kuehniella Zeller, 1879 (Lepidoptera: Pyralidae) eggs. Parasitism by these natural enemies was allowed for 48 h and the cardboards were sprayed with the herbicide nicosulfuron at 1.50 L.ha−1, along with the control (only distilled water). Nicosulfuron reduced the emergence rate of Trichogramma bruni Nagaraja, 1983 females, but increased that of Trichogramma pretiosum Riley, 1879, Trichogramma acacioi Brun, Moraes and Smith, 1984 and T. annulata females. Conversely, this herbicide increased the emergence rate of Trichogramma brasiliensis Ashmead, 1904, T. bruni, Trichogramma galloi Zucchi, 1988 and Trichogramma soaresi Nagaraja, 1983 males and decreased those of T. acacioi, Trichogramma atopovilia Oatman and Platner, 1983 and T. pretiosum males. In addition, nicosulfuron reduced the sex ratio of T. galloi, Trichogramma bennetti Nagaraja and Nagarkatti, 1973 and T. pretiosum and increased that of T. acacioi, T. bruni, T. annulata, Trichogramma demoraesi Nagaraja, 1983, T. soaresi and T. brasiliensis. The herbicide nicosulfuron was “harmless” (class 1, <30% reduction) for females and the sex ratio of all Trichogrammatidae species based on the International Organization for Biological Control (IOBC) classification. The possible hormesis effect of nicosulfuron on Trichogrammatidae species and on the bacterium Wolbachia sp. (Rickettsiales: Rickettsiaceae) was also discussed.

Residual Acute Toxicity of Some Modern Insecticides Toward Two Mirid Predators of Tomato Pests.

The successful integration of chemical and biological control strategies for crop pests depends on a thorough evaluation of the effects of pesticides on the natural enemies of pests. A case-by-case review is difficult to achieve because of the many combinations of pests, natural enemies, and crops that need to be tested. Within this framework, we tested and compared seven insecticides representative of four different modes of action (MoAs) groups on closely related predators (Miridae): flubendiamide, spirotetramat, metaflumizone, and sulfoxaflor on Nesidiocoris tenuis Reuter and flubendiamide, spiromesifen, indoxacarb, and imidacloprid on Macrolophus basicornis (Stal). We follow the standardized methodology of the International Organization for Biological Control, a sequential testing exposure scheme. The lethal effect of each insecticide was evaluated in adults after three days of contact with treated surfaces in the laboratory, extended laboratory, and semifield tests (inert substrate, tomato leaves, and tomato plant as the treated surface, respectively). Flubendiamide, spiromesifen, and spirotetramat were classified as harmless (class 1), metaflumizone was slightly harmful (class 2) but persistent, indoxacarb was harmless (class 1), and sulfoxaflor and imidacloprid were toxic (class 4) and exhibited a long residual activity. Our results suggest similarities in the acute toxicities of insecticides from the same MoA group on related species of natural enemies.

Selectivity of organic compounds to the egg parasitoid Telenomus remus Nixon (Hymenoptera: Plastygastridae)

The selectivity of insecticides, bio-protective mixtures, and biofertilizers used in organic soybean production was evaluated for adults and pupae of the egg parasitoid Telenomus remus Nixon (Hymenoptera: Platygastridae) under laboratory conditions in accordance with protocols proposed by the International Organization for Biological Control (IOBC). The products sprayed (dosage/180L of water) were: 1) Baculovírus anticarsia 140x109 cpi; 2) Bacillus thuringiensis 16.8g; 3) Azadirachtin-A, azadirachtin-B, nimbina and salamina 9.6 ppm; 4) Rotenoids 4 liters; 5) Nitrogen 1.3%, phosphorus 3.0% and total organic carbon 8.0% 3 liters; 6) Sodium silicate 2% 4 liters; 7) Copper 7% + calcium 3.3% 1.8 liters; 8) Sulfur 20% + quicklime 10% 1.8 liters; 9) Chlorpyrifos 384g (positive control); 10) Distilled H2O (negative control). The results of experiments using pupae indicate that the organic compounds were classified as harmless (Class 1), except for the copper 7% + calcium 3.3% and sulfur 20% + quicklime 10%, which were classified as slightly harmful (Class 2). The contact bioassay with adults showed that all products were classified as harmless (Class 1). Only chlorpyrifos (384g) was classified as harmful (Class 4) for both stages of the parasitoid. However, the use of this product (chlorpyrifos) is not permitted in organic farming, and even in conventional farming is recommended, where feasible, replacement of the product with one compatible with the preservation of T. remus in nature. Thus, the products tested and used in organic soybean production were considered compatible with the parasitoid eggs of T. remus.

Side-Effects of Glyphosate to the Parasitoid Telenomus remus Nixon (Hymenoptera: Platygastridae).

The aim of this study was to compare the side-effects of glyphosate to the parasitoid Telenomus remus Nixon (Hymenoptera: Platygastridae) when parasitoids were exposed to this chemical at the pupal (inside host eggs) and adult stages. Bioassays were conducted under laboratory conditions according to the International Organization for Biological Control (IOBC) standard methods for testing side-effects of pesticides to egg parasitoids. Different glyphosate-based pesticides (Roundup Original®, Roundup Ready®, Roundup Transorb®, Roundup WG®, and Zapp Qi®) were tested at the same acid equivalent concentration. Treatments were classified following the IOBC toxicity categories as (1) harmless, (2) slightly harmful, (3) moderately harmful, and (4) harmful. When tested against T. remus adults, Roundup Original®, Roundup Ready®, Roundup Transorb®, and Roundup WG® reduced parasitism 2days after parasitoid emergence, being classified as slightly harmful. Differently, when tested against T. remus pupae, all tested glyphosate-based products did not differ in their lethal effect and therefore did not reduce T. remus adult emergence or parasitism capacity, being classified as harmless. However, differences on sublethal toxicity were found. Parasitism of individuals emerging from parasitized eggs sprayed at the pupal stage of T. remus with Zapp Qi® was lower compared to control, but parasitism was still higher than 66%, and therefore, Zapp Qi® was still classified as harmless. In conclusion, all tested glyphosate-based products can be used in agriculture without negative impact to T. remus as none was classified as harmful or moderately harmful to this parasitoid when exposure occurred at the pupal or adult stages.

Lethal and sublethal effects of three insecticides on the aphid parasitoid, Lysiphlebus fabarum Marshall (Hymenoptera: Aphidiidae)

Lysiphlebus fabarum Marshall is the main parasitoid of the black bean aphid, Aphis fabae Scopoli. Lethal and sublethal effects of insecticides, thiacloprid+deltamethrin, pirimicarb and pymetrozine were evaluated on the parasitoid under laboratory conditions. One-day-old mummies were exposed to the recommended field concentration of either insecticides via dipping method. Adult emergences were reduced by 82.67, 19.98 and 10.67 % for thiacloprid+deltamethrin, pirimicarb and pymetrozine treatments, respectively. Thiacloprid+deltamethrin had the most adverse effect on the fecundity of the emerged females, while pirimicarb and pymetrozine did not have such effects. According to International organization for biological control (IOBC) insecticide toxicity classification, thiacloprid+deltamethrin resulted to be moderately harmful (E = 97.39%), whereas pirimicarb (E = 15.78%) and pymetrozine (E = 5.15%) were harmless. Thiacloprid+deltamethrin negatively affected five of the estimated demographic parameters (GRR, R0 , rm, λ and T ). Pirimicarb negatively affected GRR, R0 and T, while it had no adverse effects on rm and λ. None of the studied demographic parameters were affected by pymetrozine. Our results suggest that pirimicarb and pymetrozine can be considered as safe for L. fabarum, but that thiacloprid+deltamethrin can have serious detrimental of this parasitoid in the field.

Quality Assessment of the Commercially Available Predator Amblyseius swirskii (Acari: Phytoseiidae)

Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) is a commercially available predatory mite used to control thrips, whiteflies, and broad mites in horticultural production. The inconsistent quality of mass-produced biocontrol agents is a major concern in augmentative biological control and only a few studies have tested the post-shipment quality of commercial phytoseiids. We evaluated the post-shipment quality of A. swirskii purchased from a commercial provider in the United States. Guidelines for quality control of commercially produced natural enemies, established by the International Organization for Biological Control (IOBC), were followed. Quantity, survival, fecundity, and establishment in ornamenttal peppers (‘Explosive Ember’) were measured. The estimated quantity of A. swirskii motiles (immatures and adults) was quite variable among bran containers (20,968 ± 7,391 mites) but close to the number claimed in the label. Numbers of living A. swirskii females evaluated (n = 30) declined by less than 40% (26 ± 1.25 females) within two days of arrival and declined more than 50% by day eight (15 ± 1.23 females). No significant differences among days sampled were identified for female fecundity; however, fecundity varied considerably among containers. There was no population increase in the ornamental peppers during the two weeks following inoculation with A. swirskii. Accepted for publication 3 September 2016.

Organic products selectivity for Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)

ABSTRACT: The selectivity of different insecticides, fungicides and fertilizers used in organic soybean cropping was evaluated according to the protocols proposed by the Pesticides and Beneficial Organisms Working Group of the International Organization for Biological Control (IOBC) concerning adults and pupae of the egg parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) under laboratory conditions. Treatments 1) baculovirus anticarsia 140 x 109 cpi; 2) Bacillus thuringiensis 16.8 g; 3) azadirachtin-A, azadirachtin-B, nimbina and salamina 9.6 ppm; 4) rotenoids 4% 4 L; 5) nitrogen 1.3%, phosphorus 3.0% and total organic carbon 8.0% 3 L; 6) sodium silicate 2% 4 L; 7) copper 7% + calcium 3.3% 1.8 L; 8) sulfur 20% + quicklime 10% 1.8 L were in general safe (class 1) to both adults and pupae of T. pretiosum . Differently, chlorpyrifos (control treatment) was harmful to this parasitoid. Therefore, the utilization of the tested natural derived products in the production of organic soybean is viable, without impairing the natural biological control allowed by T. pretiosum . Furthermore, both management techniques can indeed be used together in organic cropping aiming at reaching increasing or complementary control of target pests. Chlorpyrifos use, on the other hand, whenever possible, should be replaced by other products more compatible with biological control preservation.

Effects of Atrazine-Based Herbicide on Emergence and Sex Ratio of Trichogrammatidae (Hymenoptera)

The aim of this study was to evaluate the effect of the herbicide atrazine, recommended for weed control in corn, on 10 species of Trichogrammatidae (Hymenoptera). A female of each trichogrammatid was placed individually in a test tube (no-choice) with a card containing approximately 45 Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) eggs. Parasitism by these trichogrammatids was allowed for 48 h, and the cards were sprayed with the herbicide atrazine at 6 L/ha, along with a control (distilled water). Atrazine reduced the emergence of Trichogramma bruni Nagaraja females, but increased that of Trichogramma pretiosum Riley, Trichogramma demoraesi Nagaraja, Trichogramma galloi Zucchi, and Trichogramma soaresi Nagaraja. In addition, atrazine reduced the sex ratio of T. bruni, Trichogramma atopovirilia Oatman & Platner, and Trichogramma bennetti Nagaraja & Nagarkatti, and increased that of T. demoraesi and T. soaresi. The herbicide was slightly harmful to T. bennetti and T. bruni, but was relatively harmless to the other species of Trichogrammatidae based on the standards of the International Organization for Biological Control (IOBC).

Toxicity of Insecticides Targeting Rice Planthoppers to Adult and Immature Stages of Trichogramma chilonis (Hymenoptera: Trichogrammatidae).

Planthopper-targeting insecticides, pymetrozine, thiamethoxam, buprofezin, and nitenpyram, were tested under laboratory conditions for toxicity to adults and immatures of Trichogramma chilonis Ishii, using standard tests described by International Organization for Biological Control (IOBC). In the dry film residue test, all insecticides resulted in >90% mortality in T. chilonis adults and were ranked as moderately harmful. Persistent toxicity tests revealed that nitenpyram was short-lived and the other three insecticides were of slightly persistent toxicity to the wasp adults. Effects of the insecticides on egg, larval, and prepupal stages of T. chilonis were investigated with striped stem borer as host. At the three stages of T. chilonis (within the host egg), all the insecticides reduced parasitism rate, but nitenpyram and pymetrozine applied at egg stage, buprofezin and nitenpyram at larval stage, and buprofezin and thiamethoxam at prepupal stage of T. chilonis reduced parasitism by <30% in comparison with the control, and were thus ranked as harmless. Although insecticide treatment of the three immature stages of T. chilonis all reduced wasp emergence from host eggs, only thiamethoxam applied at larval stage and buprofezin at prepupal stage resulted in >30% reduction in emergence rate as compared with the control and were categorized as harmful. Immature duration of T. chilonis was only significantly extended by nitenpyram applied to egg stage than the control. Sex ratio of emerged wasps was not affected by the treatment to immature stages. The data are of significance for IPM programs incorporating inundative release of T. chilonis for control of lepidopteran rice pests where there is heavy co-occurrence of planthoppers.

Fitness consequences of low temperature storage of Aphidius ervi

In biological control programs, storage at low temperatures is used to produce large number of individuals before inundative releases. However, an exposure to low temperatures may affect the survival of exposed individuals and some life history traits such as the daily fecundity or the longevity of the survivors. This impact on life history traits is important because they will determine the growth potential of the population. To estimate the costs of different treatments of low temperature exposure, we analyzed the main instantaneous demographic parameters of the parental generation of Aphidius ervi Haliday (Hymenoptera: Braconidae: Aphidiinae) when exposed to three storage temperatures (7, 4 and 0 °C), combined with two storage durations (one and two weeks) and two thermal regimes (constant and fluctuating), which represents a total of 12 treatments and a control. The average cohort generation time (Tc) decreased significantly after exposure to low temperature, particularly in fluctuating treatments. This means that development continues during storage. Cumulative fecundity and the net reproductive rate (R 0 ) decreased significantly for most of the storage treatments. This decrease was most pronounced in the constant temperature treatments. Females under fluctuating thermal regime produced a higher cumulative fecundity than those exposed to constant temperatures. Surprisingly, an exposure to 0 °C over one week did not affect emergence rate and fecundity whereas all other treatments did. Storage at low temperatures may affect the efficiency of inundative releases, with the exception of storage for one week at 0 °C. Moreover, cumulative fecundity and net reproductive rate (R 0 ) represent a more immediate prediction of the increase of the population after low temperature exposure than the intrinsic rate of increase (r m ), and reflect the qualities required in an inundative release context. © 2013 International Organization for Biological Control (IOBC).

Effects of soft soap and abamectin on the two spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) and predatory mite Phytoseiulus persimilis A-H (Acari: Phytoseiidae) under laboratory conditions

Soft soap at three dosages (3 ml/L, 5 ml/L and 7 ml/L) and abamectin (12.5 mg/100L) were applied to bean plants determine their residual effects on the predatory mite, Phytoseiulus persimilis A-H (Acari: Phytoseiidae) later released for the control of the two-spotted spider mite (TSSM), Tetranychus urticae Koch (Acari: Tetranychidae) under laboratory conditions. The contact toxicity of soft soap and abamectin were evaluated and classified according to IOBC(International Organization for Biological Control) standards. The soap at 3 ml/L and 5 ml/L did not supress TSSM populations and could not provide satisfactory control when compared with soap at 7ml/L and abamectin. The efficacy of soap at 5 ml/L with P. persimilis gave sufficient control of TSSM when compared with soap at 3 ml/L with P. persimilis, and the predator alone. Both the soap at 7 ml/L and abamectin in combination with the predatory mite gave satisfactory control of TSSM ,but in the abamectin treatment, the predatory mite population was not observed due to harmful effects of abamectin. However, use of soft soap at suitable dosage, with or without predatory mite, gave encouraging results for controlling TSSM but was moderately toxic at 5 ml/L and 7 ml/L P. persimilis in contact toxicity testing by causing 50.0 % and 42.3 % mortality, respectively, to adulst of P. persimilis. In addition, abamectin at 12.5 and 25 mg/L (ppm) dosages was evaluated as harmful (T) to adults of P. persimilis. Separately, soft soap caused no phytotoxicity to host plants. However, its phytotoxicity needs to be further investigated under greenhouse and field conditions.