Greenhouse Thrips Research Articles

Slow-Release Sachets of Neoseiulus cucumeris Predatory Mites Reduce Intraguild Predation by Dalotia coriaria in Greenhouse Biological Control Systems.

Intraguild predation of Neoseiulus cucumeris Oudemans (Phytoseiidae) by soil-dwelling predators, Dalotia coriaria Kraatz (Staphylinidae) may limit the utility of open rearing systems in greenhouse thrips management programs. We determined the rate of D. coriaria invasion of N. cucumeris breeder material presented in piles or sachets, bran piles (without mites), and sawdust piles. We also observed mite dispersal from breeder piles and sachets when D. coriaria were not present. Dalotia coriaria invaded breeder and bran piles at higher rates than sawdust piles and sachets. Furthermore, proportions of N. cucumeris in sachets were six- to eight-fold higher compared with breeder piles. When D. coriaria were absent, N. cucumeris dispersed from breeder piles and sachets for up to seven weeks. In earlier weeks, more N. cucumeris dispersed from breeder piles compared with sachets, and in later weeks more N. cucumeris dispersed from sachets compared with breeder piles. Sachets protected N. cucumeris from intraguild predation by D. coriaria resulting in higher populations of mites. Therefore, sachets should be used in greenhouse biocontrol programs that also release D. coriaria. Furthermore, breeder piles that provide “quick-releases” or sachets that provide “slow-releases” of mites should be considered when incorporating N. cucumeris into greenhouse thrips management programs.

Polyploidy versus endosymbionts in obligately thelytokous thrips.

BackgroundThelytoky, the parthenogenetic development of females, has independently evolved in several insect orders yet the study of its mechanisms has so far mostly focussed on haplodiploid Hymenoptera, while alternative mechanisms of thelytoky such as polyploidy are far less understood. In haplodiploid insects, thelytoky can be encoded in their genomes, or induced by maternally inherited bacteria such as Wolbachia or Cardinium. Microbially facilitated thelytoky usually results in complete homozygosity due to gamete duplication and can be reverted into arrhenotoky, the parthenogenetic development of males, through treatment with antibiotics. In contrast, genetically encoded thelytoky cannot be removed and may result in conservation of heterozygosity due to gamete fusion. We have probed the obligate thelytoky of the greenhouse thrips, Heliothrips haemorrhoidalis (Bouché), a significant cosmopolitan pest and a model species of thelytoky in the haplodiploid insect order Thysanoptera. Earlier studies suggested terminal fusion as a mechanism for thelytoky in this species, while another study reported presence of Wolbachia; later it was speculated that Wolbachia plays a role in this thrips’ thelytokous reproduction.ResultsBy using PCR and sequence analysis, we demonstrated that global population samples of H. haemorrhoidalis were not infected with Wolbachia, Cardinium or any other known bacterial reproductive manipulators. Antibiotic treatment of this thrips did also not result in male production. Some individuals carried two different alleles in two nuclear loci, histone 3 and elongation factor 1 alpha, suggesting heterozygosity. However, the majority of individuals had three different alleles suggesting that they were polyploid. Genetic diversity across both nuclear loci was low in all populations, and absent from mitochondrial cytochrome oxidase I, indicating that this species had experienced genetic bottlenecks, perhaps due to its invasion biology or a switch to thelytoky.ConclusionsGeographically broad sampling and experimental manipulation revealed low genetic diversity, absence of Wolbachia but presence of three different alleles of nuclear loci in most analysed individuals of obligately thelytokous H. haemorrhoidalis. This suggests that polyploidy may be involved in the thelytokous reproduction of this thrips species, and polyploidy may be a contributing factor in the reproduction of Thysanoptera and other haplodiploid insect orders.Electronic supplementary materialThe online version of this article (doi:10.1186/s12862-015-0304-6) contains supplementary material, which is available to authorized users.

Biomorphological variability of Frankliniella occidentalis pergande in relation to its invasion in greenhouses of Kyiv

The results of studies on distribution and trophic relations of western flower thrips in greenhouses of Kyiv are presented. On the basis of morphometric studies, the comparative analysis of plastic features of populations with bisexual and parthenogenetic modes of reproduction is performed.

Assessing the Efficiency of Different Chemical Products for Western Flower Thrips

The principal management strategy used to deal with western flower thrips in greenhouses involves the use of insecticides (R. A. Cloyd, 2009). We assessed the effectiveness of five chemical variants in five rows of tomato (36 m 2). The variants were: Pyrinex 25 NE (Clorpirifos 0.03%), Oscar 10 CE (Novaluron 0.06%), Vertimec 1.8 CE (Abamectin 0.08%), Karat-Ezeon (Lambda-chialotrin 0.02), Actara 25 WG (Thiametoxan 0.02%). Each variant was tested on a single row of tomato. Treatments were repeated four times. After each treatment, three examinations were performed: 24 hours before treatment, 24 hours after treatment and 7 days after treatment. Examinations consisted of counting direct on the plant the adults and pre-adults stages (larvae) separately. Twenty four hours after treatment the mean number of thrips per plant ranged from 39 individuals (Actara 25 WG) to 83.8 individuals (Oscar 10 CE). Seven days after treatment the mean number of thrips per plant varied between 23.5 individuals (Actara 25 WG) and 63.8 individuals (Oscar 10 CE). Regarding examination after 24 hours, our data showed that the minimum percentage of efficiency was registered for Pyrinex 25 NE and maximum for Karat-Ezeon. After a week the efficiency was 44% for Vertimec 1.8 CE and 71.1% for Karat-Ezeon. Thus we recommend Karat-Ezeon for thrips management but in combination with other monitoring tools to establish the right moment to use.

Pollen increases fitness and abundance of Orius insidiosus Say (Heteroptera: Anthocoridae) on banker plants

Banker plants are intended to enhance biological control by sustaining populations of natural enemies. Banker plants do this by providing alternative sources of food for natural enemies, such as pollen for omnivorous predators, thus decreasing the likelihood of their starvation and emigration from a cropping system when pest populations are low or absent. A banker plant system consisting of the Black Pearl pepper, Capsicum annuum ‘Black Pearl’, and the omnivorous minute pirate bug, Orius insidiosus Say (Hemiptera: Anthocoridae) has recently been proposed to improve biological control of thrips. Therefore, we studied how pollen from the Black Pearl pepper plant affects O. insidiosus fitness and abundance through a series of laboratory and greenhouse experiments. We found that a mixed diet of pollen and thrips increased O. insidiosus female longevity, decreased nymphal development time, and yielded larger females compared to a diet of thrips alone. Furthermore, O. insidiosus abundance was greater on flowering pepper plants than non-flowering pepper plants. From these results, we suggest that pollen from Black Pearl pepper banker plants could increase adult O. insidiosus abundance for the purpose of biological control in two ways: (1) reduce starvation and increase longevity of O. insidiosus when prey is absent; (2) enhance O. insidiosus fitness and fecundity when prey is present by mixing plant and prey diets. These results encourage future studies with the Black Pearl pepper as a banker plant for improving biological control of thrips in commercial greenhouses.

Diversifying arthropod assemblages of greenhouse pepper — Preliminary results

Recent years of studies have suggested that the common crab spider (Xysticus kochi) has a great potential against the western flower thrips (Frankliniella occidentalis) . The efficiency of applying a single predator against a pest however, is made uncertain by many different factors. Using a mixture of predators on the other hand, can overcome the difficulties of using a single-species agent, since different predators have different environmental demands and preying habits. Our experiments involved releasing a non-selected assemblage of arthropods, collected by sweep-net in alfalfa and stinging nettle, into greenhouse pepper stands. Interestingly, while there were twice as much thrips in the experimental greenhouses than in the control (mainly conventional) ones, crop yields were similar. The ratio of predators-preys in experimental greenhouses was not different from that in the control greenhouses, too. Probably the release of predators and lack of chemical treatments in experimental stands resulted in a 43% increase in the amount of Orius species. In search of a cost-effective, environment-friendly pest management method, the application of a mass-collected, non-selected assemblages of arthropods has a definite potential. Further investigations are needed to increase the efficiency and to monitor the potential drawbacks of this method.

PESTS OF BLUEBERRIES ON SÃO MIGUEL, AÇORES, PORTUGAL

In February and March 2006, two plots of 154 plants each of three southern high bush blueberries cultivars (Vacciniurn corymbosum 'Emerald', 'Jewel', and 'Springhigh') were planted in two locations on Sao Miguel Island, Acores, Portugal. One plot was planted near the town of Furnas, where the native mountain blueberry Vacciniu,n cylindraceuin was also planted, and a second plot, was planted near Calhetas with high bush only. At Caihetas, blueberry plantation establishment was difficult due to heavy soil, high pH and low organic matter, and only 10% of the plans survived. The blueberries at Furnas established well and leaf rust, caused by Pucciniasinun vaccinii, was observed. Symptoms included distinct yellow foliar lesions, with brown reddish pustules later in the season. 'Jewel' had the most rust infection, followed by 'Emerald' and 'Springhigh'. Foliar lesions of the rust were not observed on any of the native, V. cylindraceuin seedlings. This fungal disease exists in other European blueberry growing regions and can be managed with fungicidal sprays. The greenhouse thrips, Heliothrips haemorrhoidalis and the light brown apple moth, Epiphyas posivittana infested each of the blueberry species and was/were observed at both locations. The heaviest infestation of thrips was observed on plants of native V. cyIindraceun. The blueberry insect complex in the Azores is not very different from that in other locations where blueberries are grown and corresponding control measures are available.

Effects of cold storage on Thripobius javae (=T. semiluteus) (Hymenoptera: Eulophidae)

Thripobius javae (Girault) was introduced in 1995 from Israel into Italy to control the greenhouse thrips, Heliothrips haemorrhoidalis (Bouché). Following introduction, successive augmentative releases of this parasitoid gave unsatisfactory and contradictory results, mainly due to the difficulty in synchronising its availability in sufficient number at the time of release. Efficient storage of this biological control agent could improve its current production and use. The effects of different sets of storage techniques at a single temperature and with a combination of different temperatures and instars on several fitness traits (residual developmental time to adult emergence after the end of storage, pupal mortality, longevity with and without hosts and progeny of emerged adults) were evaluated in order to determine the best conditions for storing the parasitoid. For the pupal stage, increasing storage up to 14 days, at 10°C, gave only a moderate reduction (33%) of a modified composite quality index of its fitness. In contrast, when adults were stored for more than 10 days, at 15°C, residual longevity and progeny were reduced significantly. A combination of two temperatures (10 and 15°C) for pupal storage and a combination of pupal (10°C) and adult (15°C) storage had detrimental effects on parasitoid fitness. Temperatures of storage lower than 15 and 10°C had detrimental effects on adults and pupae, respectively.

Characterization of bacterial symbionts in Frankliniella occidentalis (Pergande), Western flower thrips

Many insects have associations with bacteria, although it is often difficult to determine the intricacies of the relationships. In one such case, facultative bacteria have been discovered in a major crop pest and virus vector, the Western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). Several bacterial isolates have been studied in Netherlands greenhouse thrips populations, with molecular data indicating that these bacteria were similar to Escherichia coli, although biochemical properties suggested these microbes might actually be most similar to plant pathogenic bacteria in the genus Erwinia. We focused on the bacterial flora of the Hawaiian Islands thrips population where these gut bacteria were first reported in 1989. We also analyzed a German population and a 1965 California population preserved in ethanol. Culture and culture-independent techniques revealed a consistent microflora that was similar to the Netherlands isolates studied. The similarity among thrips microbes from multiple populations and environments suggested these bacteria and their hosts share a widespread association. Molecular phylogeny based on the 16S rRNA gene and biochemical analysis of thrips bacteria suggested two distinctive groups of microbes are present in thrips. Phylogenetic analysis also revealed support for one thrips bacterial group having a shared ancestry with Erwinia, whereas the second group of thrips bacteria fell out with E. coli, but without support. Although species-specific relationships were indeterminable due to the conservative nature of 16S, there is strong indication that thrips symbionts belong to two different genera and originated from environmental microbes.

３種アザミウマ類に対するアカメガシワクダアザミウマの捕食能力

The predation of adult female Haplothrips brevitubus(Karny) (Thysanoptera: Phlaeothripidae) on 3 species of greenhouse thrips was investigated. The number of secondstage larvae of Thrips palmi, Frankliniella occidentalis, and Frankliniella intonsa consumed by a H. brevitubus female increased with the prey density. The maximum predation number per day against second-stage larvae were 8.7 for T. palmi, 9.4 for F. occidentalis, and 8.5 for F. intonsa, when only thrips were provided, and 16.1 for T. palmi, 14.0 for F. occidentalis, and 8.2 for F. intonsa when the pollen of strawberry was provided along with thrips. These results show a predatory ability almost equal to that of other enemies such as Amblyseius eharai and Amblyseius cucumeris. Therefore, H. brevitubus could be an effective biological control agent for these thrips.

First results concerning the efficacy of entomopathogenic nematodes against Hercinothrips femoralis (Reuter)

The efficacy of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis bacteriophora against larvae and adults of banded greenhouse thrips, Hercinothrips femoralis, was studied under laboratory conditions. The activity of the biological agents under study was determined at three different temperatures (15, 20, and 25°C), with concentration of 200 infective juveniles per individual (larva or adult), a day:night ratio of 4:20 and relative humidity of 95 %. The experiment was conducted in plastic rearing vessels on French bean leaves with a slightly modified version of a method used for studying the bionomics of thrips. The mortality rate of the thrips was determined four days after the application of the nematode suspension. Temperature had significant influence on adult pest mortality, but no significant effects were found with nematode species. Neither temperature nor nematode species had significant effect on larval mortality, which ranged from 23 % (S. feltiae at 25°C) to approximately 50 % (H. bacteriophora at 15 and 25°C). Mortality of adults was significantly influenced only by temperature, with the nematodes being most efficient at 25°C (approximately 30 % mortality by H. bateriophora). The results of our research showed that foliar application of entomopathogenic nematodes might be a relatively efficient way for controlling H. femoralis, but the optimization of environmental factors would likely improve their efficacy further.

Effect of temperature on the development longevity and oviposition of greenhouse thrips (<i>Heliothrips haemorhoidalis</i>) on lemon fruit

Greenhouse thrips (Heliothrips haemorrhoidalis) is a major pest of horticultural crops worldwide and in New Zealand it is particularly damaging on citrus avocados and ornamentals Heliothrips haemorrhoidalis development oviposition and longevity were determined at five constant temperatures (16 18 20 23 and 25 C) on unripe Yenben lemon fruit Total developmental time (egg to adult) ranged from 729 days at 16 C to 284 days at 25 C The rate of H haemorrhoidalis oviposition was highest at 25 C with an average of 14 eggs laid per day Mean adult longevity ranged from 899 days at 25 C to 124 days at 16 C It was estimated that 4198 degreedays above a lower threshold temperature of 101 C were required to complete development from egg to adult The developmental time predictions obtained from the degreeday model were validated under variable field conditions Actual developmental times were generally within one day of times predicted by the model

First results concerning the efficacy of entomopathogenic nematodes against Hercinothrips femoralis (Reuter)

The efficacy of the entomopathogenic nematodes Steinernema feltiae and Heterorhabditis bacteriophora against larvae and adults of banded greenhouse thrips, Hercinothrips femoralis, was studied under laboratory conditions. The activity of the biological agents under study was determined at three different temperatures (15, 20, and 25°C), with concentration of 200 infective juveniles per individual (larva or adult), a day:night ratio of 4:20 and relative humidity of 95 %. The experiment was conducted in plastic rearing vessels on French bean leaves with a slightly modified version of a method used for studying the bionomics of thrips. The mortality rate of the thrips was determined four days after the application of the nematode suspension. Temperature had significant influence on adult pest mortality, but no significant effects were found with nematode species. Neither temperature nor nematode species had significant effect on larval mortality, which ranged from 23 % (S. feltiae at 25°C) to approximately 50 % (H. bacteriophora at 15 and 25°C). Mortality of adults was significantly influenced only by temperature, with the nematodes being most efficient at 25°C (approximately 30 % mortality by H. bateriophora). The results of our research showed that foliar application of entomopathogenic nematodes might be a relatively efficient way for controlling H. femoralis, but the optimization of environmental factors would likely improve their efficacy further.

Note: First record in crete ofHercinothrips femoralis in greenhouse banana plantations

In 2004 the banded greenhouse thrips,Hercinothrips femoralis (Reuter) (Thysanoptera: Thripidae), was recorded for the first time in greenhouse-grown organic banana in the area of Sitia (northeastern Crete). Banana fruits were severely damaged by the thrips infestation and a typical smoky-red discoloration of the fruit was observed. Pest control was poor using either high-pressure washing with potassium fatty acids, or commercially available thrips predatorsNeoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae) andOrius laevigatus (Fieber) (Hemiptera: Anthocoridae). During 2005H. femoralis was also found causing severe damage in conventional banana plantations in Arvi, the main banana-growing area of Crete.

Evaluation of phytoseiid predators for control of western flower thrips on greenhouse cucumber

Ten predatory mite species, all phytoseiids, were evaluated for control of western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), on greenhouse cucumber. This study was done to further improve biological control of thrips on this crop. Neoseiulus cucumeris (Oudemans) is at present used for biological control of thrips in greenhouses. Compared to this species, Typhlodromalus limonicus (Garman & McGregor), Typhlodromips swirskii (Athias-Henriot) and Euseius ovalis (Evans) reached much higher population levels resulting in a significantly better control of thrips. T. limonicus was clearly the best predator of WFT. Also Euseius scutalis (Athias-Henriot) increased to higher populations levels than N. cucumeris, but without controlling the thrips, probably because of an unequal distribution of this predator on the plant. Iphiseius degenerans (Berlese), Neoseiulus barkeri (Hughes), Euseius finlandicus (Oudemans) and Typhlodromus pyri (Scheuten) did not establish better than N. cucumeris. A non-diapausing exotic strain of N. cucumeris did not differ from the North European strain. The best performers in this study were all of sub-tropical origin. T. limonicus, T. swirskii and E. ovalis have good potentials for controlling not only thrips but also whiteflies. Factors affecting the efficacy of phytoseiids on greenhouse cucumbers are discussed.

Franklinothrips; a pantropical Thysanoptera genus of ant-mimicking obligate predators (Aeolothripidae)

The Aeolothripidae genus Franklinothrips Back is redefined with a key provided to the 14 species recognised worldwide, of which F. brunneicornis from New Caledonia and F. strasseni from Nepal are described as new. Most of the species appear to be bisexual and localised in distribution, but F. vespiformis is usually unisexual and is found in many tropical countries, here being recorded from Australia for the first time. All of the species are probably predatory, as adults and larvae, three species having been promoted as biological control agents against pest thrips in European greenhouses. Comments are given on predation and ant-mimicry amongst Aeolothripidae.

Density, dispersal, and feeding impact of western flower thrips (Thysanoptera: Thripidae) on flowering chrysanthemum at different spatial scales

Abstract. 1. This study evaluated the effect of dispersal on the density and feeding impact of a phytophagous insect in relation to the spatial distribution of its host plants.2. The interaction between density, dispersal, and feeding impact of western flower thrips on flowering chrysanthemum was quantified at three spatial scales, with infested and uninfested plants either isolated in 0.25 m2 individual cages, or enclosed together in 2.25 m2 communal cages or 75 m2 greenhouses.3. In individual cages, the rate of dispersal from chrysanthemum plants to blue sticky traps increased with the density of thrips for females but not males. Uninfested plants consistently had fewer thrips when they were individually caged rather than enclosed with plants infested with adults, indicating that dispersal mediates inter‐plant distribution of thrips.4. The feeding impact of thrips on inflorescences was evaluated using the absorbance of ethanol extracts at wavelengths characteristic of yellow carotenoid pigments associated with chrysanthemum inflorescences (415, 445, and 472 nm). Increasing absorbance of extracts with increasing density of thrips per inflorescence suggests that feeding by thrips results in ruptured cells leaching carotenoid pigments.5. In communal cages, the distribution of thrips was uniform for infested and uninfested plants, whereas the density and feeding impact of thrips in greenhouses were higher for infested than uninfested plants. These results suggest that short‐range dispersal by adults homogenises the density and feeding impact of thrips among host plants only on a small spatial scale.

A technique for rearing <i>Megaphragma</i> spp an egg parasitoid of greenhouse thrips

A technique for rearing <i>Megaphragma</i> spp an egg parasitoid of greenhouse thrips

The greenhouse thrips, Heliothrips haemorrhoidalis, and its generic relationships within the subfamily Panchaetothripinae (Thysanoptera: Thripidae)

AbstractThe subfamily Panchaetothripinae, comprising 35 genera and 98 species, includes several pest species of which the most notorious is the greenhouse thrips, Heliothrips haemorrhoidalis. In an attempt to establish the sister-group of Heliothrips, the relationships of this genus to 31 of the other genera in the subfamily were examined cladistically, using 35 parsimony-informative morphological characters. The analysis indicated that there was no support for two of the three tribes into which this subfamily is customarily arranged, the Monilothripini and the Panchaetothripini, but weak support for the tribe Tryphactothripini. No clear sister-group relationship could be identified for the New World genus Heliothrips, although it grouped with three old world genera Australothrips, Retithrips and Rhipiphorothrips. It is concluded that a morphological data set is not capable of producing a robust phylogeny of the Panchaetothripinae, and that the subject requires re-examination using molecular data.

Analysis of binomial sampling data for estimating thrips densities on ornamental plants

Compared with standard sampling methods binomial sampling reduces the time required to assess densities of pest species Such sampling is promoted as a practical procedure for use by nonspecialists A leaf sampling method was used to estimate the density of greenhouse thrips on a viburnum hedge at different stages of thrips population growth Three methods were used to relate the proportion of leaves infested to the mean density of thrips Sample size curves were calculated and compared at 10 and 25 levels of precision The sample sizes required for density estimation at both levels of precision differed between methods The difficulties in developing binomial sampling plans are discussed