Predatory Bug Orius Laevigatus Research Articles

Perspectives of using Artemia salina Leach (Crustacea, Anostraca) cysts for the rearing of a predatory bug Orius laevigatus (Fieber) (Heteroptera, Anthocoridae)

Predatory bug Orius laevigatus is a promising agent for biological control of aphids, thrips, white ies, spider mites, and other pests of vegetables and berries. Its application in greenhouses is limited by high rearing cost which is particularly determined by using of such an expensive food as eggs of the grain moth Sitotroga cerealella and other moths. Laboratory experiments showed that O. laevigatus nymphs and adults can feed on much cheaper cysts of a brine shrimp, Artemia salina . Nymph survival and female fecundity with the alternation of feeding with A. salina cysts and S. cerealella eggs were less than 20% lower than those with feeding on the grain moth eggs. Considering much more substantial (10-15 times) di erence in the cost of these foods we conclude that alternation of A. salina cysts and S. cerealella eggs is promising to increase the economic feasibility of O. laevigatus use for biological control of pests in greenhouses.

Effectiveness of various insecticides and predatory bug, Orius laevigatus (Fieber, 1860) (Hemiptera: Anthocoridae) releases on Thrips hawaiiensis (Morgan, 1913) (Thysanoptera: Thripidae) in lemon, Citrus limon (L.) (Rutales: Rutaceae), orchard in Mersin (Türkiye)

The important invasive thrips species Hawaiian flower thrips, Thrips hawaiiensis (Morgan, 1913) (Thysanoptera: Thripidae) was first reported in Türkiye in 2015. Since then, it has been causing damage in lemon orchards. This study was conducted to reveal the most effective insecticides, the most effective spraying time and the efficacy of biological control. For this purpose, the effectiveness of five insecticides (480 g/l spinosad, 25% spinetoram, 100 g/l spirotetramat, 50% flonicamid, 240 g/l tau-fluvalinate), effect of three spray programs and effectiveness of predatory bug Orius laevigatus (Fieber, 1860) (Hemiptera: Anthocoridae) were tested in a lemon orchard [Citrus limon (L.) (Rutales: Rutaceae)] in Erdemli district of Mersin province in 2018 and 2019. In order to determine the most effective spraying time, three spray programs were tested. In Program 1, two sprays during the flowering period were applied. In Program 2, two sprays were applied, one at petal fall and the other at the small fruiting stage. In Program 3, one spray at petal fall and two sprays in the fruiting stages were applied. According to the results, 240 g/l tau-fluvalinate and 50% flonicamid showed the lowest efficacy of the insecticides in the three programs. Spinetoram was found the most effective of the others. Insecticide applications to control T. hawaiiensis during the flowering period (Program 1) had low efficacy. Program 3 was found to be the most effective. Predatory bug O. laevigatus, as a biological control agent was found to have a potential efficacy for suppressing T. hawaiiensis populations.

Comparative Evaluation of Reactions of the Western Flower Thrips Frankliniella occidentalis Perg. (Thysanoptera, Thripidae) and the Predatory Bug Orius laevigatus Fieber (Heteroptera, Miridae) to Pongamia pinnata (L.) Pierre Oil

This paper presents comparative assessment of the reaction of the western flower thrips Frankliniella occidentalis and the predatory bug Orius laevigatus to the seed oil of Pongamia pinnata (L.) Pierre. This oil had repellent and toxic effects on the adult and larval thrips, and also reduced the number of laid eggs. The predatory bug O. laevigatus was highly sensitive to P. pinnata oil under various methods of exposure, even at a concentration of 0.75%, which was the lowest concentration effective against the thrips. The observed side effects of the oil on O. laevigatus determine the need either for development of a specific approach for combined use of the oil and this entomophage, or for replacing O. laevigatus with some other predator resistant to P. pinnata oil.

Effect of biopreparation verticillin M based on the extract from entomopathogenic fungus Lecanicillium muscarium and its insecticidal metabolites on the entomophages in greenhouses

Plants protection from pests in greenhouses, including the production of meristem potatoes, needs greatly in environmentally safe and effective preparations. The effect of the biopreparation verticillin M on the base of insecticidal metabolites of the entomopathogenic fungus Lecanicillium muscarium (= Verticillium lecanii) on a number of entomophages has been studied for the purpose of their joint application. The biopreparation is non-toxic in the maximum concentration (0.5 %) for Encarsia formosa in the nymph stage, the preimaginal stages of the predatory midge Aphidoletes aphidimyza, for predatory mite Phytoseiulus persimilis (mobile stages), and for larvae of predatory bug Orius laevigatus. Verticillin M is a weak toxic for imago A. aphidimyza and has no effect on the fecundity of surviving imago midge, hatching and subsequent survival of larvae and pupae. The mortality of imago O. laevigatus reached 22 % and 61 % at concentration of bioprepations 0.25 % and 0.5 %, respectively. The individual fractions responsible for the insecticidal activity of verticillin M showed a little toxicity to imago O. laevigatus. The combined use of verticillin M with imago of A. aphidimyza and O. laevigatus is possible in concentrations of 0.1–0.25 %.

Olfactory Response of the Predatory Bug Orius laevigatus (Hemiptera:Anthocoridae) to the Aggregation Pheromone of Its Prey, Frankliniella occidentalis (Thysanoptera: Thripidae).

Herbivore natural enemies base their foraging decision on information cues from different trophic levels but mainly from plant odors. However, the second trophic level (i.e., the herbivorous prey) may also provide reliable infochemical cues for their natural enemies. We have evaluated the role of the aggregation pheromone from Frankliniella occidentalis (Pergande) as a potential kairomone for its natural enemy, the predatory bug Orius laevigatus (Fieber). For this purpose, we have analyzed the response of O. laevigatus to (R)-lavandulyl acetate and neryl (S)-2-methylbutanoate, the two major components of the thrips aggregation pheromone. These compounds have been offered to O. laevigatus adult females and nymphs of the predatory bugs both in separate and as specific (1:1 or 1:2.3) blends, in experiments involving a dual choice Y-tube olfactometer. None of the compounds attracted adults or nymphs when they were individually supplied. Conversely, they were significantly attracted to both adults and nymphs when offered as a blend. A 1:2.3 (R)-lavandulyl acetate:neryl (S)-2-methylbutanoate blend was attractive to both nymphs and adults, while a 1:1 blend elicited response only in nymphs. These results suggest that specific blends of these compounds from the aggregation pheromone may be used as an attractant to O. laevigatus. The results of this work highlight the importance of studying olfactory responses of natural enemies for a better understanding of their foraging behavior. Potential uses of these results in future studies are discussed.

The behavioral response of the predatory bug Orius laevigatus Fieber (Heteroptera, Anthocoridae) to synthetic volatiles

The behavioral response of the predatory bug Orius laevigatus Fieber to synthetic analogues of secondary plant metabolites was studied. Two compounds most attractive to the bug, methyl salicylate and methyl jasmonate, were identified by olfactometer experiments and pot bioassays. The use of natural volatiles or their analogues as attractants for beneficial insects can significantly improve the efficiency of biological pest control methods.

Dissemination of the entomopathogenic fungi, Lecanicillium longisporum and L. muscarium, by the predatory bug, Orius laevigatus, to provide concurrent control of Myzus persicae, Frankliniella occidentalis and Bemisia tabaci

The simultaneous use of two biocontrol agents for the concurrent control of three pest species was investigated. Leaf disc bioassays were conducted to establish a suitable method (surface dosing) for the dissemination of an entomopathogenic fungus ( Lecanicillium longisporum or L. muscarium) by the predatory bug Orius laevigatus. Predatory bugs surface dosed with fungal conidia successfully disseminated conidia onto sweet pepper leaf discs. Most (98%) of the peach-potato aphids ( Myzus persicae) that were subsequently maintained on the leaf discs became infected with the pathogen and died within 5 days. However, fungal conidia disseminated by surface dosed predatory bugs did not infect and kill the western flower thrips ( Frankliniella occidentalis) or the sweetpotato whitefly ( Bemisia tabaci). Plant trials were performed to assess the efficacy of using predatory bugs surface dosed with L. longisporum as an effective means of controlling M. persicae and F. occidentalis populations. The results indicated that the number of aphids and thrips were significantly lower (66% and 95%, respectively) on the plants where surface dosed predatory bugs were used as a control measure compared with plants where the fungal pathogen alone was used and were statistically comparable to the numbers on plants where the predatory bug alone was used. The potential for using this dual approach is discussed in the context of improved biological control of glasshouse pests.

Herbivore benefits from vectoring plant virus through reduction of period of vulnerability to predation

Herbivores can profit from vectoring plant pathogens because the induced defence of plants against pathogens sometimes interferes with the induced defence of plants against herbivores. Plants can also defend themselves indirectly by the action of the natural enemies of the herbivores. It is unknown whether the defence against pathogens induced in the plant also interferes with the indirect defence against herbivores mediated via the third trophic level. We previously showed that infection of plants with Tomato spotted wilt virus (TSWV) increased the developmental rate of and juvenile survival of its vector, the thrips Frankliniella occidentalis. Here, we present the results of a study on the effects of TSWV infections of plants on the effectiveness of three species of natural enemies of F. occidentalis: the predatory mites Neoseiulus cucumeris and Iphiseius degenerans, and the predatory bug Orius laevigatus. The growth rate of thrips larvae was positively affected by the presence of virus in the host plant. Because large larvae are invulnerable to predation by the two species of predatory mites, this resulted in a shorter period of vulnerability to predation for thrips that developed on plants with virus than thrips developing on uninfected plants (4.4 vs. 7.9 days, respectively). Because large thrips larvae are not invulnerable to predation by the predatory bug Orius laevigatus, infection of the plant did not affect the predation risk of thrips larvae from this predator. This is the first demonstration of a negative effect of a plant pathogen on the predation risk of its vector.

Factors affecting the distribution of a predatory mite on greenhouse sweet pepper

The predatory mite Neoseiulus cucumeris is used for biological control of phytophagous mites and thrips on greenhouse cucumber and sweet pepper. In a previous study, N. cucumeris provided effective control of broad mite but was only rarely found on the sampled leaves, raising questions about the factors affecting N. cucumeris distribution. To determine the distribution of N. cucumeris, leaves of pepper plants were sampled three times per day: just after sunrise, at noon and just before sunset for two years and throughout a 24 h period in one year. The presence of other mites and insects was recorded. Biotic (pollen) and abiotic (temperature, humidity) factors were monitored from the three plant levels. The effect of direct and indirect sunlight on the mites was assessed. N. cucumeris was found primarily in flowers; however, the mite's distribution was affected by other predators (intraguild predation); in the presence of the predatory bug Orius laevigatus virtually no mites occurred in the flowers. Whereas temperature and humidity varied from the top to the lower level of the plants, apparently neither these factors nor the presence of pollen outside the flowers influenced mite distribution. N. cucumeris was found to be negatively phototropic; therefore N. cucumeris were pre-conditioned to light by rearing under light conditions for 4 months before being released. The light-reared mites were initially more numerous during the noon sampling period, however, rearing conditions caused only a temporary and non-significant change in distribution.

Residual activity of abamectin and spinosad against the predatory bugOrius laevigatus

The residual effect of two biopesticides, abamectin and spinosad, on the predatory bugOrius laevigatus (Fieber) (Hemiptera: Anthocoridae) was tested using a laboratory and an extended laboratory method. Experiments were conducted in the spring and summer 2000. The LD50s on the 2nd and 5th nymphal instar and the adult stage, were lower for abamectin than for spinosad. The toxicity of each product on the 2nd instar and adults was significantly greater than on the 5th nymphal instar. Abamectin was much more persistent in spring than in summer. Spray deposits (at the recommended rate of 10 ppm a.i. for leafminer control) were toxic for 1 month in spring, whereas in summer they were no longer toxic after 2 weeks. Spinosad summer spray deposits (recommended rate of 250 ppm a.i. for leafminer and caterpillar control) were not toxic after 5 residual days.

Sequential testing scheme for the assessment of the side-effects of plant protection products on the predatory bug Orius laevigatus

This paper describes a number of test methods, to beused in a sequential scheme, for testing the side-effects ofplant protection products on anthocorid bugs. Orius laevigatuswas used as test species. A `worst case' laboratory method wasdeveloped for evaluating the effect on mortality of the nymphsand the reproduction of the adults. An extended laboratory methodgives information on the effect of pesticides on adults undermore natural conditions. A semi-field test is executed in smallplots under field (glasshouse) conditions. Finally a field testsimulates the conditions in a commercial crop. For harmfulchemicals, both a laboratory and a semi-field persistence testwas developed to determine the safety period after which thepredatory bugs can be re-introduced in the greenhouse withoutbeing adversely affected. The total result of this sequentialscheme should indicate whether, and with what restrictions, aparticular pesticide can be implemented in IPM programs in whichO. laevigatus is used for control of western flower thrips(Frankliniella occidentalis). Twenty-two pesticides were testedincluding five fungicides, twelve insecticides and fiveacaricides. The fungicides captan, carbendazim, sulphur, thiram,tolylfluanid and the insecticides or acaricides pymetrozine,pyriproxyfen, tebufenozide and hexythiazox were harmless in the`worst case' laboratory test and thus did not need furthertesting. Imidacloprid, diafenthiuron, lufenuron, tebufenpyrad,abamectin, pyridaben and bifenthrin were harmful in thesemi-field test and should, in the tested concentrations, betternot be used simultaneously with the predatory bug. Theinsecticide dichlorvos was found harmful but short-lived in thepersistence test; it should be used before the introduction ofthe predatory bug O. laevigatus only when a safety period of 7days is respected. Pirimicarb was slightly toxic in thesemi-field test but short-lived. In IPM programs this aphicideshould be used at a low application frequency.

Interactions mediated by predators in arthropod food webs

Studies on interactions among plants, herbivores and natural enemies are important for understanding population dynamics of species in food webs, but they are also important for the practice of pest control with natural enemies. Biological control programs heavily rely on the occurrence of trophic cascades, where the addition of one natural enemy causes a decrease of pest densities and an increase of plant biomass. However, when more that one natural enemy is used to control various pests in the same system, artificial food webs are created and simple tritrophic interactions change to more complicated ones. The occurrence of complex interactions and omnivory in these food webs may modify the sign and the strength of direct effects of natural enemies on pests. In this paper, we show and discuss the experimental results on interactions mediated by predators in an artificial food web that occurs on cucumber plants in greenhouses where biological control is applied. The two pests in this food web are the two-spotted spider mite Tetranychus urticae Koch, and the western flower thrips Frankliniella occidentalis (Pergande). The predatory mites Phytoseiulus persimilis Athias-Henriot and Neoseiulus californicus (McGregor) are used to control spider mites, and the generalist predatory bug Orius laevigatus (Fieber) and a specialist predatory mite Neoseiulus cucumeris (Oudemans) are predators of thrips. Results from behavioural studies showed that some of these species are attracted to the same patch and do not avoid each other's presence. We show some complex interactions arising from the meeting of these species: (a) the intraguild predation by O. laevigatus on P. persimilis, (b) the use of spider-mite web as a refuge by thrips larvae against their predators. The consequences of such interactions for population dynamics of predators and prey and their implications for success of biological control are discussed.

Attraction of a generalist predator towards herbivore‐infested plants

AbstractThe occurrence and strength of interactions among natural enemies and herbivores depend on their foraging decisions, and several of these decisions are based on odours. To investigate interactions among arthropods in a greenhouse cropping system, we studied the behavioural response of the predatory bug Orius laevigatus (Fieber) (Hemiptera: Anthocoridae) towards cucumber plants infested either with thrips (Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae)) or with spider mites (Tetranychus urticae Koch (Acari: Tetranychidae)). In greenhouse release‐recapture experiments, the predatory bug showed a significant preference for both thrips‐infested plants and spider mite‐infested plants over clean plants. Predatory bugs preferred plants infested with spider mites to plants with thrips. Experience with spider mites on cucumber leaves prior to their release in the greenhouse had no effect on the preference of the predatory bugs. However, this experience did increase the percentage of predators recaptured. Y‐tube olfactometer experiments showed that O. laevigatus was more attracted to odours from plants infested with spider mites than to odours from clean plants. Thus, O. laevigatus is able to perceive odours and may use them to find plants with prey in more natural conditions. The consequences of the searching behaviour for pest control are discussed.

Absence of odour‐mediated avoidance of heterospecific competitors by the predatory mite Phytoseiulus persimilis

AbstractArthropods use odours associated with the presence of their food, enemies and competitors when searching for patches. Responses to these odours therefore determine the spatial distribution of animals, and are decisive for the occurrence and strength of interactions among species. Therefore, a logical first step in studying food web interactions is the analysis of behaviour of individuals that are searching for patches of food. We followed this approach when studying interactions in an artificial food web occurring on greenhouse cucumber in the Netherlands. In an earlier paper we found that one of the predators of the food web, the predatory mite Phytoseiulus persimilis Athias‐Henriot, used to control spider mites, discriminates between odours from plants with spider mites, Tetranychus urticae Koch, and plants with spider mites plus conspecific predators. The odours used for discrimination are produced by adult prey in response to the presence of predators, and probably serve as an alarm pheromone to warn related spider mites. Other predator species may also trigger production of this alarm pheromone, which P. persimilis could use in turn to avoid plants with heterospecific predators. We therefore studied the response of the latter to odours from plants with spider mites and 3 other predator species, i.e. the generalist predatory bug Orius laevigatus (Fieber), the polyphagous thrips Frankliniella occidentalis and the spider‐mite predator Neoseiulus californicus (McGregor). Both olfactometer and greenhouse release experiments yielded no evidence that P. persimilis avoids plants with any of the 3 heterospecific predators. This suggests that these predators do not elicit production of alarm pheromones in spider mites, and we argue that this is caused by a lack of coevolutionary history. The consequences of the lack of avoidance of heterospecific predators for interactions in food webs and biological control are discussed.

Behaviour and indirect interactions in food webs of plant-inhabiting arthropods

With the increased use of biological control agents, artificial food webs are created in agricultural crops and the interactions between plants, herbivores and natural enemies change from simple tritrophic interactions to more complex food web interactions. Therefore, herbivore densities will not only be determined by direct predator–prey interactions and direct and indirect defence of plants against herbivores, but also by other direct and indirect interactions such as apparent competition, intraguild predation, resource competition, etc. Although these interactions have received considerable attention in theory and experiments, little is known about their impact on biological control. In this paper, we first present a review of indirect food web interactions in biological control systems. We propose to distinguish between numerical indirect interactions, which are interactions where one species affects densities of another species through an effect on the numbers of an intermediate species and functional indirect interactions, defined as changes in the way that two species interact through the presence of a third species. It is argued that functional indirect interactions are important in food webs and deserve more attention. Subsequently, we discuss experimental results on interactions in an artificial food web consisting of pests and natural enemies on greenhouse cucumber. The two pest species are the two-spotted spider mite Tetranychus urticae and the western flower thrips, Frankliniella occidentalis. Their natural enemies are the predatory mite Phytoseiulus persimilis, which is commonly used for spider mite control and the predatory mites Neoseiulus cucumeris and Iphiseius degenerans and the predatory bug Orius laevigatus, all natural enemies of thrips. First, we analyse the possible interactions between these seven species and we continue by discussing how functional indirect interactions, particularly the behaviour of arthropods, may change the significance and impact of direct interactions and numerical indirect interactions. It was found that a simple food web of only four species already gives rise to some quite complicated combinations of interactions. Spider mites and thrips interact indirectly through resource competition, but thrips larvae are intraguild predators of spider mites. Some of the natural enemies used for control of the two herbivore species are also intraguild predators. Moreover, spider mites produce a web that is subsequently used by thrips to hide from their predators. We discuss these and other results obtained so far and we conclude with a discussion of the potential impact of functional indirect and direct interactions on food webs and their significance for biological control.

La toxicité du diflubenzuron, pyriproxyfen, imidacloprid et diafenthiuron sur le prédateurOrius laevigatus (Fieber) (Heteroptera : Anthocoridae)

The susceptibility of the predatory bugOrius laevigatus (Fieber) to the insect growth regulators diflubenzuron, pyriproxyfen, the nitroguanidine insecticide imidacloprid and the thiourea compound diafenthiuron was investigated in the laboratory. Fifth-instar nymphs were exposed to formulated materials of each compound and adults were exposed to formulated materials of diafenthiuron and imidacloprid. In each case, exposure via ingestion and residual contact was tested. Pyriproxyfen was harmless toO. laevigatus nymphs by both ways of exposure. The respective LC50-values of diflubenzuron via ingestion and residual contact were 229.9 and 391.1 mg a.i./l. Diafenthiuron did not cause significant mortality to fifth-instar nymphs and adults via ingestion but was toxic by residual contact with LC50-values of 329.4 mg a.i./l and 125.9 mg a.i./l for nymphs and adults respectively. Imidacloprid proved to be the most toxic compound with LC50-values of 1.1 and 0.04 mg a.i./l for nymphs and 2.1 and 0.3 mg a.i./l for adults, via ingestion and residual contact, respectively. The results suggest that use of pyriproxyfen in an integrated pest management programme will not cause any problems but that imidacloprid, and to a lesser extent, also diflubenzuron and diafenthiuron could be harmful to the predator.

Laboratory test method to evaluate the effect of 31 pesticides on the predatory bug,Orius laevigatus (Het: Anthocoridae)

A laboratory test method was developed to evaluate the pesticide toxicity on the predatory bugOrius laevigatus (Fieber). Newly hatched first-instar nymphs ofO. laevigatus were exposed to spray deposits of pesticides that were sprayed on the glass plates of a drum cell at the manufacturer’s recommended maximum dosage. Nymphal mortality and oviposition of surviving adults were recorded.