Lygocoris Pabulinus Research Articles

Diversity of the Entomocomplex of the Grass Stand of a Hemp Field in The North-Eastern Forest-Steppe of Ukraine

The agrobiocenosis of the grass stand of hemp field is a specific plant biotope, which is a place of shelter, feeding, resettlement, and breeding for many insect populations, which in one way or another affecting the growth, development and yield of hemp plsnts. Taking this into consideration awareness of the species composition of phytophagous insects as well as the complex of their natural enemies and neutral species became especially relevant awareness due to the necessary to develop an effective system of protection of hemp in the context of current conditions. The aim of the research is to improve the ecologically oriented system of hemp protection by means of studying the taxonomic composition of entomofauna in the grass stand, as well as the trophic and ecological structure of insect groups associated with that habitat. The studies was conducted in 2019-2021 on the basis of the Northeast Agricultural Institute of the National Academy of Agrarian Sciences out during the vegetation of plants by means of mowing with a standard entomological net every ten days, from 10.00 till 15.00 o’clock when the insects were the most active. The current taxonomic composition of entomocomplex of the grass stand in hemp field is represented by 174 species of insects that belong to 76 families and 9 orders. The Coleoptera turned out to be the largest in terms of the species diversity and the number of individuals (56 species from 16 families and 74.6% of the number of captured insects). Were also detected insects from the orders Hymenoptera (31 species from 15 families), Hemiptera (30 species from 11 families), Diptera (20 species from 12 families), Homoptera (17 species from 8 families), Lepidoptera (12 species from 8 families), Orthoptera (4 species from 3 families), Neuroptera (3 species from 2 families), Thysanoptera (one species) were also detected. In the trophic structure of the entomofauna in grass stand of hemp field, 85.9% of the number and 59.8% of the species diversity account for phytophagous insects. Pests of hemp were 39 species of insects from 22 families, and 6 orders. Among them, 36 species, which accounted for 18.7% of the total number of specimens, were polyphagous and three, or 81.3%, were specialized species. The presence of insect pests in the grass stand of hemp field was characterized by oligodominance, as evidenced by quantitative and qualitative data, and indices of species diversity. Thus, the dominance structure is represented by one eudominant (Psylliodes attenuata – 81.1%), one subdominant (Mordellistena parvula – 4.72%), four recedents (Lygus pratensis, L. rugulipennis, Lygocoris pabulinus, Stictocephala bisonia – 8.6%) and, 33 subrecedents (5.58%). The obtained research results will be used in order to solve the problems related to the danger of basic phytophagous insects during the vegetation period of cannabis sativa plants and to develop a modern environmentally-oriented strategy to control their numbers and harmfulness

Seasonal Development of Plant Bugs (Heteroptera, Miridae): Subfamily Mirinae, Tribe Mirini

The available data on seasonal development of plant bugs (Mirinae: Mirini) are reviewed, and the level of understanding of their seasonal adaptations is evaluated. The ecological responses involved in control of seasonal development of 14 species from 5 genera (Adelphocoris, Apolygus, Lygus, Lygocoris, and Stenotus) are analyzed in detail. All the studied species are broadly polyphagous and produce a varying number of annual generations in different climatic zones. The studied members of four genera, namely Adelphocoris, Apolygus, Lygocoris, and Stenotus, hibernate at the embryonic stage while bugs of the genus Lygus do so at the adult stage. Some species of the genera Adelphocoris and Lygus, in particular Lygus pratensis, have acquired a pronounced ability to fly over long distances, facilitating the search for flowering vegetation. However, unlike many insects that make distant migrations in the state of adult diapause, females of plant bugs of the genus Adelphocoris migrate with mature eggs in their oviducts. This feature allows Adelphocoris females to successfully colonize new areas even in the absence of males, since females do not need additional mating in the colonized area. For the majority of Mirini species experimentally studied in the laboratory, the temperature parameters of development and the sum of effective temperatures needed to complete the full generation were calculated. When combined with observations done under natural conditions, these data allowed us to determine the exact number of annual generations produced by the species or population. The role of day length in the control of seasonal development was analyzed in detail in three species of the genus Adelphocoris: A. triannulatus, A. suturalis, and A. lineolatus. The conditions inducing and terminating adult diapause were studied in detail in Lygus hesperus in the southern United States. The seasonal development of Lygocoris pabulinus is an unusual example of an obligate host plant change during the year. The diapausing eggs of this species overwinter in the tissues of woody plants but the nymphs then migrate onto herbaceous plants on which the summer generations develop. Such a seasonal strategy is more characteristic of aphids (Homoptera) than of true bugs (Heteroptera). On the whole, our analysis of the available data indicates that the control of seasonal development of plant bugs of the subfamily Mirinae is still poorly understood despite their high economic importance. Most reports deal with a small number of experimentally studied species and are limited to the data on temperature parameters of development. The important role of photoperiodic adaptations in the control of seasonal development has been demonstrated only for a few well-studied species (e.g., Adelphocoris triannulatus); such data are crucial for analysis and prediction of seasonal development and spread of harmful and beneficial insects, since the seasonal cycle of each population of a given species is strictly synchronized with the local conditions.

New and resurgent insect pests on low trellis hops

Abstract Selective insecticides have largely displaced broad‐spectrum products on cultivated hops, allowing a resurgence of historic pests and new ones to arise. The present study reports the incidence of 30 insect species from four insect Orders and 14 Families feeding on aphid susceptible and/or aphid‐resistant low trellis hop cultivars in south‐east England and at three West Midland sites. Three are Kent Red Data Book species [Adoxophyes orana (Lepidoptera: Tortricidae), Hypena rostralis (Lepidoptera: Noctuidae) and Psylliodes attenuatus (Coleoptera: Chrysomelidae)] and three are DEFRA biodiversity action plan priority insects [Acronicta rumicis, Melanchra persicariae (Lepidoptera: Noctuidae) and Spilosoma lubricipedia (Lepidoptera: Arctiidae)]. Six common lepidopteran species severely damaged hop cones (Adoxophyes orana, Autographa gamma, Epiphyas postvittana, Eupitheca assimilata, Mamestra brassicae and S. lubricipedia), whereas Biston betularia, H. rostralis, Melanchra persicariae and Phlogophora meticulosa did not. European corn borer (Ostrinia nubilalis) feeding on hops in Kent are the so‐called E‐pherotype. Lygocoris pabulinus (Hemiptera: Miridae) caged on developing flowering lateral shoots reduced numbers of developing hop cones by 38% and cone weight by 42%, whereas Liocoris tripustulatus caused no losses. Companion plants in the drive alleys between rows of hops reduced the incidences of L. tripustulatus and S. lubricipedia.

Further Studies on Sex Pheromones of Female Lygus and Related Bugs: Development of Effective Lures and Investigation of Species-Specificity

Mirid bugs (Heteroptera: Miridae) are important pests of many crops worldwide. In previous work by others and ourselves, several species of Lygus bugs were shown to produce blends of three compounds, hexyl butyrate, (E)-2-hexenyl butyrate, and (E)-4-oxo-2-hexenal. These have been proposed as components of the female-produced sex pheromones, but attraction of males to synthetic lures has been difficult to demonstrate. We studied the volatiles released by females of four species: Lygus rugulipennis, Lygus pratensis, Lygocoris pabulinus, and Liocoris tripustulatus. Analyses of volatiles from individual, undisturbed insects showed that the three compounds were produced in species-specific blends, by females only, or in greater quantities by females than by males. The three compounds were loaded into pipette tips, which released the defined blends over at least 30days. Traps baited with the blend for L. rugulipennis caught more males than traps baited with virgin females, with all three compounds required for maximum attractiveness. Traps baited with the specific blends for each of the four species caught males of three of the species, indicating considerable cross-attraction. There is evidence that other, non-chemical factors, such as time-of-day of production of pheromone, contribute to species-specificity of attraction. This is the first report of consistent attraction of Lygus bugs to synthetic lures in the field.

Arthropod pests of currant and gooseberry crops in the U.K.: their biology, management and future prospects

Approximately 10-12 species of Ribes plants are cultivated for fruit production, mainly blackcurrants, red- and whitecurrants and gooseberries. These crops are increasingly recognized as rich sources of vitamin C and anthocyanins, with production rising by 24% in Europe subsequent to 1998. To date, research into insect pests of Ribes has been fragmented, with little appreciation of how changes in climate and agronomic practices affect biology. 2 We review 12 key pests of currant and gooseberry crops in Northern Europe, with specific emphasis on their biology and current management options. These are blackcurrant leaf curling midge Dasineura tetensi, blackcurrant sawfly Nematus olfaciens, common gooseberry sawfly Nematus ribesii, European permanent currant aphid Aphis schneideri, redcurrant blister aphid Cryptomyzus ribis, currant-sowthistle aphid Hyperomyzus lactucae, European gooseberry aphid Aphis grossulariae, woolly vine scale Pulvinaria vitis, common green capsid Lygocoris pabulinus, winter moth Operophtera brumata, clear wing moth Synanthedon tipuliformis and blackcurrant gall mite Cecidophyopsis ribis. 3 It is anticipated that global climate change could lead to increases in the incidence of some aphids through increased overwintering survival and longer seasonal activity. Moreover, changes in management practices such as increased cropping densities (from 5400 ha −1 to 8700 ha −1 ) and machine harvesting could lead to pest outbreaks

Oviposition preference of Lygocoris pabulinus (Het., Miridae) in relation to plants and conspecifics

Abstract: To predict possible locations of Lygocoris pabulinus (L) in the field during the summer, we determined their oviposition preference under summer conditions. With L. pabulinus reared on potato, oviposition preference was determined for potato, tomato or green bean. As preference may depend on larval or early adult experience, the oviposition preference of bugs reared on green bean for three generations, and of bugs captured from the field 12 h prior to the experiment was also determined. All females showed a strong preference for potato plants, on which fecundity was higher. Hence, although L. pabulinus is a generalist in its feeding habits, the summer generation seems to be an oviposition specialist. Aggregation of ovipositing females does not seem to occur; similar amounts of eggs were oviposited in plants with clip cages containing conspecifics as in plants without conspecifics. More eggs were oviposited in damaged plants than in undamaged plants. Plant volatiles released upon damage may aid L. pabulinus females in finding suitable oviposition sites.

Mate location in the green capsid bug, Lygocoris pabulinus

AbstractHeadspace extracts from female Lygocoris pabulinus (L.) (Heteroptera: Miridae) as well as female leg extracts attracted male L. pabulinus in Y‐track olfactometer bioassays. In contrast, only female leg extracts were active in the vibration bioassay. Male extracts had no activity at all in either bioassay. When the female leg extract was analysed by coupled gas chromatography‐electroantennography (Z)‐9‐pentacosene and (Z)‐7‐pentacosene were EAD‐active. (Z)‐9‐Pentacosene and sometimes (Z)‐7‐pentacosene were also observed in female headspace extracts. EAG responses could be obtained for (Z)‐9‐pentacosene. A mixture of (Z)‐9‐pentacosene and (Z)‐7‐pentacosene in the ratio 5 : 1 elicited vibration behaviour in males. The results indicate that these alkenes are important cues for male L. pabulinus in mate location behaviour.

Coupled gas chromatographic-electroantennographic responses of Lygocoris pabulinus (L.) to female and male produced volatiles

GC profiles of airborne volatiles produced by adult female and male green capsid bugs, Lygocoris pabulinus, were almost identical with the exception of a small amount of mono-alkenes being produced only in females. Coupled gas chromatography/electroantennogram detector (GC-EAD) recordings revealed that three compounds were consistently EAD-active. These were hexyl butyrate, (E)-2-hexenyl butyrate and (E)-4-oxo-2-hexenal. Male antennae reacted strongly to these three compounds whereas female antennae gave no or little response. These compounds may be important chemical signals for male L. pabulinus in their longrange communication with conspecifics.

Influence of host plants on sexual communication in the herbivorous bug Lygocoris pabulinus

Host plant volatiles may be involved in the sexual communication of insects in several ways. In the pheromone-producing sex, these volatiles may affect pheromone production or release and, in the receptive sex, plant volatiles may have a synergistic effect on the attraction to sex pheromone. We conducted three types of experiments to determine if and how plant volatiles are involved in the sexual communication of Lygocoris pabulinus (L.) (Heteroptera: Miridae), the females of which attract males. In a one-choice cylinder bioassay, females were offered to males on two different plants, belonging to different plant families, i.e. potato leaves and goosefoot leaves, to determine if specific plant volatiles were involved in the attraction of males towards females. Females on potato leaves were as attractive as females on goosefoot leaves, but significantly more attractive than females without plant material. The latter result suggests an interaction between females and potato leaves. However, in two-choice flying and walking bioassays, using delta traps in a wind tunnel and a vertical Y-track olfactometer, males were attracted to females irrespective of the presence of potato leaves. This difference in result is probably due to the fact that in the latter assays females were confined with pollen as an alternative food source, while females in the one-choice assay had access to water only, so that they may have suffered from malnutrition. Males in the one-choice assay were also attracted to potato leaves from which females had been removed, indicating that attractive components from females are deposited and adsorbed to the substrate. Plants are probably only indirectly involved in sexual communication, their surface merely functioning as a substrate from which pheromone is released. Males may subsequently be attracted to such plants or substrates. Clean plant material was not attractive to L. pabulinus males, hence plant volatiles alone do not seem to be used by these males as possible mate location cues.

Disruption of sexual communication in the mirid bug Lygocoris pabulinus by hexyl butanoate

Summary1 The metathoracic scent gland in Lygocoris pabulinus contains mostly hexyl butanoate. As secretions of this gland in Heteroptera may serve as an alarm pheromone, we determined whether hexyl butanoate is released by disturbed bugs, and whether this compound disrupts sexual attraction of L. pabulinus males towards females.2 Undisturbed males and females, and disturbed males released less than 100 ng/h hexyl butanoate, whereas disturbed females released a highly variable amount, ranging from 25 ng/h to more than 1 μg/h.3 In the field, traps with virgin females and rubber septa containing 20 mg hexyl butanoate, caught a total of one male in a month. In control traps without hexyl butanoate, 36 males were caught in the same period.4 In Y‐track olfactometer tests, males were not attracted to virgin females when a dispenser with 20 mg hexyl butanoate was placed in the bottle with females. Males were attracted to females when the dispenser was placed downwind from the females, but upwind from the point of male release.5 These results suggest that males are not repelled by hexyl butanoate, but that this compound inhibits sex pheromone release in females. Application possibilities for pest management are discussed.

Close-range attraction in Lygocoris pabulinus (L.).

Males of the green capsid bug, Lygocoris pabulinus, exhibit a specific courtship behavior, i.e., a vibration of the abdomen. When both live and dead females were offered to males, this vibration behavior was elicited in most of the males tested. When females were dissected into separate body parts, heads, wings, and legs elicited equal responses, while thorax plus abdomen elicited a much lower response. When separate body parts were extracted, the leg extracts elicited significantly stronger responses than any other extract. This suggests that female L. pabulinus legs are either the source of a close-range sex pheromone or that pheromone is accumulated on the legs due to grooming behavior. The leg extracts contained several hydrocarbons such as n-alkenes, n-alkanes, and some methylalkanes. Female extracts contained more (Z)-9-pentacosene and male extracts contained more (Z)-9-heptacosene. Substrates on which females had walked elicited similar responses as female legs, indicating that the pheromone is deposited on the substrate. This enlarges the functional range of low-volatility compounds, which are thought to function only when sexes are in close vicinity or in contact.

Polyandry in the mind bug Lygocoris pabulinus (L.)—effects on sexual communication and fecundity

Summary Lygocoris pabulinus females are polyandrous under laboratory conditions (Groot et al., 1998). As the insect mating system affects sexual communication and thus sexual behavior as a whole, we studied sperm transfer, storage and displacement in L. pabulinus. To be able to fully understand these processes, detailed information on the female reproductive tract is essential. Therefore, we first studied the female genitalia in detail. The bursa copulatrix consists of four plates, and a spermatheca is connected anteriorly to the bursa. At copulation a spermatophore is formed in the spermatheca. The spermatophore is compartmentalized, consisting of a sperm-containing portion, a large sperm-free portion and a mating plug. After 24 h the spermatophore has partially disintegrated. The mating plug is still intact but reduced in size. Sperm are found throughout the spermatheca and in the median and lateral oviducts where fertilization most likely takes place. The amount of male-derived substances transferred to females during first matings was ca. 5.2% relative to male body weight. To understand the effects of matings on the sexual communication, we determined sexual attraction of mated females at long and close range. At long range females were unattractive for only 1–2 h after mating, while they remained attractive at close range. Mated males were not attracted to virgin females for 2 h after mating, and only 23% of the tested males mated again within 24h. Together, these results suggested a high paternal investment that may affect reproductive output. To determine if this is the case, and hence if multiple matings affect fecundity and/or longevity, we conducted two oviposition experiments. From these experiments no positive effects on total fecundity or longevity in multiply mated females were apparent.

On-line Thermal Desorption–Gas Chromatography of Intact Insects for Pheromone Analysis

By using a thermodesorption system (TDS) together with a programmable temperature vaporizer (PTV) injector, we confirmed the composition of the sex pheromone of Adoxophyes orana (Lepidoptera: Tortricidae) and Campylomma verbasci (Heteroptera: Miridae) from a single insect per analysis. Intact females and males or pheromone glands were placed in the oven part of the TDS, which was subsequently heated. The compounds released were transferred to the PTV, which was cooled to −150°C. Injection was on a dual-column GC by heating the PTV rapidly to 250°C. The major sex pheromone compounds of A. orana were found only in the pheromone gland of females. Male and female C. verbasci showed fingerprint-identical chromatograms, except for the two sex pheromone compounds, which were present only in females. No distinct differences were found in compounds released from female and male Lygocoris pabulinus (Heteroptera: Miridae). The advantages of this rapid method are the high sensitivity and the low degree of degradation and contamination. This technique was effective in analyzing small insects by gas chromatography–mass spectrometry (GC-MS) without prior manipulation, such as solvent extraction or distillation.

Sex-related perception of insect and plant volatiles in Lygocoris pabulinus

We recorded electroantennograms of male and female Lygocoris pabulinus antennae to 63 insect and plant volatiles. EAGs were between 100 and 500 μV. Overall, male EAGs were about twice the size of female EAGs. In both sexes, largest EAGs were recorded to (E)-2-hexenyl butanoate and (E)-2-hexen-1-ol. Response profiles were similar in both sexes. However, male antennae were more sensitive to a number of esters, especially the butanoates and pentanoates. Female antennae were more sensitive to nine of the 19 plant volatiles, i.e., to hexan-1-ol, heptan-1-ol, 1-octen-3-ol, 2-heptanone, (R)-carvone, linalool, geraniol, nerol, and methyl salicylate. Sexual differences in responses suggest that males are more sensitive to insect-produced pheromone-type compounds, whereas females are more sensitive to plant compounds for their orientation towards oviposition sites.

Copulation behaviour of Lygocoris pabulinus under laboratory conditions

AbstractAs a prerequisite to the elucidation of the sex pheromone of the green capsid bug Lygocoris pabulinus (L.), we studied the bug's reproductive development and behaviour. When kept under long‐day conditions (L18:D6) at 25 °C, both males and females start to copulate 4 days after the final moult. Second matings occur in some females, even on consecutive days. The premating period is 10 min on average and copulation lasts 1 to 2 min. At long range, when males are attracted to traps baited with live females, we did not observe a specific calling position of the females. At short range, a characteristic courtship behaviour of the females was not observed either. Males showed a characteristic vibration of the abdomen, which was repeated several times before copulation. This behaviour can be used as a bioassay to test potential sex pheromone compounds.

Two years of trials with biological control programmes in all -year-round chrysanthemums

In trials conducted in 1989 and 1990 in Kent and Worcestershire (England), an IPM programme for the range of pests of chrysanthemums was evaluated. The main target pest was Frankliniella occidentalis but biocontrols for Trialeurodes vaporariorum, aphids (mainly Myzus persicae) and Tetranychus urticae were also used. Anthocoris nemorum adults and nymphs collected from the wild gave good control of F. occidentalis in Kent in 1989 at the rate of 1 per 10 m2 per week. In 1990 trials, A. nemorum also gave good thrips control at 1 per 20 m2 per week, providing that thrips numbers were low at the start of the trial. Anthocorids also preyed on aphids, spider mites and whitefly scales. Lygocoris pabulinus was not affected by A. nemorum and caused some flower damage in the IPM trial. In the 1990 trial in Worcestershire, a combination of Verticillium lecanii (Mycotal) weekly sprays at 1 g litre−1 of water and Neoseiulus cucumeris predators applied weekly at 50 per m2 also gave good control of F. occidentalis. Conditions for the use of Mycotal were excellent, with humidity in the crop normally above 85% once the blackout screens were drawn. The effect of Mycotal was seen within 2 weeks on the whitefly population, as many infected adults and scales were found. No infected thrips were seen at any time, but it is thought that the Mycotal did have a significant effect upon the thrips population. N. cucumeris (Thripex-Koppert) did not establish well on chrysanthemums when applied in bran from a shaker bottle. However, this predator may establish in larger numbers when slow-release bags are used. Further work on this aspect is needed. The commercial availability of predatory bugs such as anthocorids or Orius spp. would undoubtedly increase the uptake of IPM methods by growers.

Lygus Bugs: Crop Resistance and Physiological Nature of Feeding Injury

Plant bugs of the family Miridae are serious pests of seed, fruit, and nursery crops throughout the world. The genus Lygus Hahn has at least 9 species of major importance to agriculture in North America, Europe, and Asia (Kelton 1975). The bulk of this review will deal with these species, but where appropriate, reference will be made to the following additional species in the family Miridae: alfalfa plant bug, Adelophocoris lineolatus (Goeze); cotton fleahopper, Pseudatomoscelis seriatus (Reuter); Lygocoris pabulinus (L.), and Taylorilygus vosseleri Poppius. Whenever possible, papers dealing with crop resistance relationships of lygus bugs and related mirids are used for discussion.

Comparison of Four Insecticides for the Control of the Common Green Capsid, Lygocoris pabulinus (L.) (Heteroptera‐Miridae), on Apple Trees

SUMMARYSingle sprays of DDT, malathion, azinphos‐methyl and vamidothion were applied to apple trees at petal fall in 1967 and 1968 for the control of Lygocoris pabulinus in a commercial orchard in the west of England. The degree of control was assessed by sampling the number of capsids and newly damaged twigs in each treatment after spraying. Control on all sprayed trees was virtually complete in 1967. In the following year DDT, azinphos‐methyl and vamidothion gave 74, 67 and 81 per cent control respectively, whereas no L. pabulinus was found on malathion‐treated trees and only 0.2 per cent of the twigs assessed for damage showed recent feeding punctures. It was concluded that vamidothion and azinphos‐methyl gave as good control of this species as DDT and that malathion gave better control.

Insect Transmission of Fireblight

SUMMARYThe following insects, after being allowed contact with a culture of Erwinia amylovora and then enclosed with trusses of primary blossom of pear or apple, were found to transmit fireblight disease to (a) pear: an aphid species, Meligethes sp., Bombus terrestris, B. hortorum. Apis mellifera, Andrena varians, Hoplocampa testudinea, Eristalis tenax, Neoascia sp., Scopeuma stercorarium; and to (b) apple: Andrena varians, H. testudinea, E. tenax and Lucilia sp. In preliminary tests the following transmitted the disease to vegetative shoots of (a) pear: Psylla simulans, Philaenus spumarius, Lygocoris pabulinus and Orthotylus marginalis; and (b) apple: Psylla simulans.