Glasshouse Pests Research Articles

Enhancing the oral and topical insecticidal efficacy of a commercialized spider venom peptide biopesticide via fusion to the carrier snowdrop lectin (Galanthus nivalis agglutinin).

Spear®-T sold as a contact foliar spray for the control of glasshouse pests such as aphids, thrips, spider mites and whiteflies, contains the recombinant spider venom peptide GS-ω/κ-HxTx-Hv1h (named as GS-ω/κ-HxTx-Hv1a by Vestaron) as the active ingredient. Here we investigate whether fusion of the peptide to snowdrop lectin, (Galanthus nivalis agglutinin; GNA) enhances the efficacy of this venom peptide towards aphid pests. Recombinant GS-ω/κ-HxTx-Hv1h (HxTx-Hv1h) and an HxTx-Hv1h/GNA fusion protein were produced using the yeast Pichia pastoris. Purified proteins showed comparable toxicity when injected into lepidopteran (Mamestra brassicae) larvae, but significant differences in oral and contact activity towards aphids. HxTx-Hv1h had comparable acute oral toxicity to pea (Acyrthosiphon pisum) and peach potato (Myzus persicae) aphids with respective Day (2) median lethal concentration (LC50 ) values of 111 and 108 μm derived from diet assays. The fusion protein also showed comparable oral toxicity to both species but D2 LC50 values were >3-fold lower (35 and 33 μm for pea and peach potato aphids, respectively) as compared to HxTx-Hv1h. Topically applied toxin and fusion protein, but not GNA, caused significant reductions in pea aphid survival. Contact effects on mortality were significantly greater for aphids exposed to fusion protein as compared to toxin alone. Whole aphid fluorescence microscopy and immunoblotting suggest that improved efficacy is due to enhanced persistence of HxTx-Hv1h when fused to GNA following internalisation of ingested or topically applied proteins. This is the first study to report on the insecticidal activity of HxTx-Hv1h towards aphids and results suggest that a fusion protein-based approach offers opportunities to significantly enhance oral and contact efficacy of naturally derived toxins, such as HxTx-Hv1h, towards crop pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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.

Effect of host plant, prey species and intergenerational changes on the prey preferences of the predatory mirid Macrolophus caliginosus

The outdoor establishment of non-native biocontrol agents released for inundative control of glasshouse pests is determined primarily by two factors: ecophysiological compatibility with local climate, particularly winter cold tolerance, and ability to locate and utilise wild prey. Observations on the number and diversity of acceptable wild prey as part of an assessment of establishment potential therefore overlap with more focused studies to determine host range. This study investigated two aspects of the interactions between biocontrol agents and non-target prey that are rarely considered in tests for establishment or host range: the role of different host plant–prey associations in modifying the development and reproduction of biocontrol agents, and the longer term sustainability of such relationships beyond the single generation observed in most laboratory studies. Using the glasshouse whitefly (Trialeurodes vaporariorum) predator Macrolophus caliginosus Wagner (Hemiptera: Miridae) as a case study, the mirid was able to sustain viable populations over three generations on the related cabbage whitefly Aleyrodes proletella (Linnaeus) (Hemiptera: Aleyrodidae) and the aphid Myzus persicae (Sulzer) (Hemiptera: Aphididae), including when these prey were feeding on different host plants (Chinese cabbage, cabbage and Brussels sprout). However, the rate of development, fecundity and mortality of the predator varied between the different prey and host plant combinations, and in all cases differed than when feeding on its glasshouse prey T. vaporariorum reared on tobacco (Nicotiana tabacum). The results are discussed in the light of the current debate on methods for conducting host range testing as part of an environmental risk assessment.

Effect of temperature on development, overwintering and establishment potential of Franklinothrips vespiformis in the UK

AbstractThis study investigated the effect of temperature on the development and overwintering potential of the predatory thrips Franklinothrips vespiformis (Crawford) (Thysanoptera: Aeolothripidae), a biological control agent used against glasshouse pests in continental Europe and Israel. Developmental rates increased linearly with rearing temperatures. It was estimated that 304.9 degree days, above a lower threshold temperature of 11.9 °C, were required for F. vespiformis to complete development from egg to adult eclosion. The effect of low temperatures (–5, 0, and 5 °C) was examined on adult female and larval survival. Subsequent reproductive and developmental attributes of survivors were also investigated. Lethal time experiments indicated that larval stages are more cold tolerant than adult F. vespiformis females. Surviving larvae increased their developmental times to adults with decreasing temperature and increasing exposure periods and second instars were significantly more successful than first instars in reaching adulthood. Surviving adult females decreased their oviposition rate with decreasing temperature and increasing exposure periods, and exposures to low temperatures affected the number of viable eggs produced. The results are discussed in the context of overwintering and establishment potential of F. vespiformis in the UK in the event of introducing the predatory thrips as a biological control agent against glasshouse pests.

Glasshouse Pests and Microbial Control

Glasshouse Pests and Microbial Control

Predation capacity of two predatory laelapid mites on soil‐dwelling thrips stages

AbstractThe life cycle of the Western Flower Thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), one of the most important glasshouse pests, includes a soil passage composed of three instars that deserve more attention in terms of biocontrol strategies. It has been repeatedly reported that two polyphagous predatory mites, Stratiolaelaps miles (Berlese) and Hypoaspis (Geolaelaps) aculeifer (Canestrini) (Acari: Laelapidae), also prey on these thrips stages, in addition to several other soil inhabiting prey species. However, the potential thrips consumption rates have never been quantified for these predatory mites. Therefore, an arena experiment was carried out to investigate the potential predation rates of the two mites on second instar larvae, prepupae, and pupae of F. occidentalis. In addition, the fecundity on the thrips diet was assessed and compared to oviposition rate on a nematode prey. All thrips instars were accepted as prey by each mite species. Females of H. aculeifer preyed on 3.5 (± 0.5) thrips instars and laid 2.5 (± 0.87) eggs per day, whereas females of S. miles preyed on 1.64 (± 0.3) thrips and laid 0.8 (± 0.53) eggs. Males of both species killed 0.6 (± 0.3) thrips per day. The fitness of the two predatory mites on F. occidentalis as prey and their suitability as biocontrol agents are elucidated. Reasons for reduced thrips control in the soil environment, in contrast to the results obtained in arena assays are discussed.

The pathogenicity of Vairimorpha necatrix (Microspora: Microsporidia) against the tomato moth, Lacanobia oleracea (Lepidoptera: Noctuidae) and its potential use for the control of lepidopteran glasshouse pests.

A droplet feeding technique was used to feed known amounts of Vairimorpha necatrix (Kramer) spores to larvae of the tomato moth, Lacanobia oleracea (L) in order to assess the susceptibility of this lepidopteran pest to the pathogen. All first- to fourth-instar larvae died as a result of ingesting 1000 or more V necatrix spores. Two forms of death were observed, which were dependent on the dose and the age of the insect when treated. For first-instar larvae, rapid death (within 6days of dosing) occurred after ingestion of 2000 spores, whereas lower doses resulted in a proportion of larvae dying from chronic infection (microsporidiosis). For more advanced stages, increasing spore doses were required to give rapid death, such that a dose of 200,000 spores was needed to give 80% mortality within 6 days for third-instar larvae. Rapid death was not observed in fourth- to sixth-instar larvae. In all cases successful pupation and adult emergence were much reduced compared with non-infected larvae. Suspensions of V necatrix were sprayed on to tomato (Lycopersicon esculentum Mill) plants maintained in small glasshouses prior to infestation of the plants with L oleracea larvae. The numbers and biomass of pest larvae retrieved from the plants sprayed with V necatrix were significantly reduced by up to 40% and 70%, respectively, compared with plants sprayed with water (control). Similarly, plants sprayed with V necatrix showed a reduction in damage of up to 45% compared with the control plants.

Lasioseius fimetorum: A soil-dwelling predator of glasshouse pests?

Female lifespan and reproduction, in terms of numberof larvae produced, of the soil-dwelling predatorymite Lasioseius fimetorum Karg (Acari:Podocinidae) fed on mould mites (Tyrophagusputrescentiae [Schrank] [Acarina: Acaridae]) wereinvestigated by laboratory experiments at 20 °C,as were the mite's consumption rates of various prey.After a preoviposition period of 10.7 days, L.fimetorum produced progeny at a daily rate of 0.7.The oviposition period lasted 23.6 days and a total of19.4 progeny were produced per female. Females livedfor 38.6 days. Eggs of the Collembola Isotomurusspp. (Collembola: Isotomidae) were consumed in thelargest amount by L. fimetorum followed by mouldmite nymphs, larvae and pupae of thrips (Frankliniella occidentalis [Pergande] [Thysanoptera:Thripidae]), eggs of the Collembola Micrisotomaspp. (Collembola: Isotomidae), Isotomurus spp.nymphs and sciarid larvae (Bradysia pauperaTuomikoski and B. tritici (Coquillet) [Diptera:Sciaridae]). Immature drain flies (Psychoda spp.[Diptera: Psychodidae]) were not consumed by L.fimetorum. The suitability of L. fimetorum forbiological control of glasshouse pests withsoil-dwelling stages is discussed in comparison withanother predatory mite Hypoaspis miles Berlese(Acarina: Hypoaspididae).

Quarantine glasshouse pests in Poland and their control1

The new Polish quarantine list has been operative since 1995. It consists of two parts: list A comprises organisms prohibited for import; list B consists of plants, plant products and harmful articles and organisms whose import is prohibited. Some of the pests in list A have occurred in Poland. Methods of controlling these species are presented in this paper.

Glasshouse quarantine pests for the EPPO region and measures recommended by EPPO and the EU to prevent their spread1

The EPPO A1 and A2 quarantine lists (with corresponding specific quarantine requirements) and Annexes I and II of EU Directive 77/93 (with requirements in Annex IV) cover a number of important glasshouse quarantine pests: Liriomyza spp., Bemisia tabaci and the viruses it transmits, Frankliniella occidentalis, tomato spotted wilt tospovirus, Thrips palmi, Aculops fuchsiae, Helicoverpa and Spodoptera spp., Opogona sacchari and Radopholus similis. Most frequently, the requirements made to exporting countries for these pests centre on country or area freedom, place of production freedom (usually over the last growing season), treatment of plants immediately before dispatch. Because many of the plants concerned have a wide host range, there is some difficulty in deciding which plant species should be regulated, or whether cut flowers, fruits or vegetables should be regulated as well as plants for planting. The requirements for some of these glasshouse pests are among the broadest included in the EPPO and EU system (e.g. all plants for planting, except seeds and bulbs, for T. palmi). The recommended requirements are generally well harmonized between EPPO and the EU, except in respect of the categories of exporting countries considered. The EU requirements frequently put neighbouring non‐EU European or Mediterranean countries on the same basis as the most remote continents. Such an approach does not seem justifiable to EPPO.

Dutch quarantine strategies applied to glasshouse pests1

The Dutch strategies to prevent the establishment of quarantine pests in glasshouse crops fall within the EU framework for preventing the introduction and spread of quarantine pests. Import inspections are mainly carried out at the place of destination of the consignment, thus enabling the inspection of unpacked consignments. There is an extensive monitoring programme for imported propagation material. Monitoring of places of production where imported material may be kept contributes to early detection of pests that are introduced despite import requirements and import inspections. Early detection is considered of major importance for eradication. Monitoring focuses mainly on plants for planting, as these present substantially higher phytosanitary risks than plants for consumption. On the initiative of trade and industry, a programme for accreditation of importers has been established, and insurance for importers and producers is under investigation. To be accredited and to be considered for insurance coverage, importers must comply with a set of measures aimed at minimizing the risk of introducing quarantine pests.

Review of the status of glasshouse quarantine pests in EPPO countries1

The situation of Liriomyza spp. (L. bryoniae, L. huidobrensis, L. trifolii), Bemisia tabaci, Frankliniella occidentalis, Helicoverpa armigera, Spodoptera littoralis, tomato spotted wilt tospovirus (TSWV), impatiens necrotic spot tospovirus (INSV) and any other introduced glasshouse pests of current interest is presented for each of the 12 countries of northern and central Europe represented at the EPPO Conference at Pruhonice (CZ, 1998‐10‐13/15). These pests are in general established in the south of the EPPO region.

Occurrence and chemical control of introduced ornamental glasshouse pests in Poland1

Fourteen new pests were found in Polish commercial glasshouses on ornamental crops in 1982/1998 as a result of international trade with EU countries. They included: the insects Bemisia tabaci, Chaetanaphothrips orchidii, Frankliniella occidentalis, Lichtensia viburni, Liriomyza trifolii, Liriomyza huidobrensis, Opogona sacchari and Spodoptera littoralis; the mites Cecidophyopsis hendersoni, Polyphagotarsonemus latus, Steneotarsonemus laticeps and Tyrophagus neiswanderi; the nematodes: Paratylenchus besoekianus and Radopholus similis. The actual situation of these pests in Poland and recommended methods for their control are given.

Biological control in Hungary: present situation and possibilities1

Biological control has already achieved certain results in Hungary, especially against soil‐borne fungi and glasshouse pests. Nevertheless, experience has shown that locally found biological agents, however effective, could not be developed into registered, ready‐for‐sale plant protection products because of the lack of companies willing to invest. Biological control in Hungary is therefore limited to the conservation of natural antagonistic flora and fauna and to the application of imported biopesticides and bioagents, which are subject in Hungary to a registration procedure similar to that for chemical plant protection products. Current work includes the development of an anti‐nematode product from a local strain of Arthrobotrys oligospora, application techniques for a local mirid Dicyphus hyalinipennis against insect pests, studies with native and imported strains of the nematodes Steinernema and Heterorhabditis against soil‐borne insect pests, and introduction techniques for the chrysomelid Zygogramma sutularis against the weed Ambrosia elatior.

Ovipositional behaviour of Macrolophus caliginosus (Heteroptera: Miridae) on tobacco leaves

AbstractThe ovipositional behaviour of the mirid predator Macrolophus caliginosus Wagner, a potential biological control agent of glasshouse pests, was studied in detail using a modified video camera technique. In the laboratory, females laid their eggs in the leaves of tobacco plants. They remained generally motionless on the main veins of the leaves, raised their body, folded the rostrum towards the thorax and extended their ovipositor when selecting a site in which to oviposit. The ovipositor was inserted into the plant tissue by a downward and forward thrust of the body and contractions of the abdominal muscles. After a period of immobility, the ovipositor was retracted and the insect's body and organs returned to their initial positions. This behaviour was preceded and followed by extensive rostral exploration of the oviposition site. In most females the same area was explored before and after egg-laying and the ovipositor was inserted approximately in the middle of the selected area. The sequence and pattern of ovipositional behaviour varied between females.

Predators with a future as bioagents against glasshouse pests

As a result of the application of Encarsia formosa, Phytoseiulus persimilis and Bacillus thuringiensis, and of the decreased use of pesticides, we have observed the spontaneous appearance of natural enemies not normally present in Bulgarian glasshouses. Clitostethus arcuatus has proved a competitive species with E. formosa on Nicotiana glauca, green capsicum and Hibiscus syriacus, attacked by Trialeurodes vaporariorum. On cucumber and capsicum plants infested respectively by Aphis gossypii and Myzus persicae, Cryptolaemus montrouzieri was established after spontaneously entering an experimental glasshouse. Some trials were carried out with the polyphagous bug Podisus maculiventris under laboratory conditions. It was able to use larvae of T. vaporariorum, M. persicae and A. gossypii as prey. On this basis, it seems quite promising to include this predator in IPM programmes as an additional bioagent against certain glasshouse pests during the autumn-winter-spring period.

Situation of glasshouse pests in Hungary1

The area of protected crops in Hungary is about 5300 ha. Most of it is under plastic, the area under glass being only about 250 ha. Vegetable growing makes up 80%, mostly on private farms. The main crops are capsicum, tomato and cucumber. On relatively small areas, ornamentals, principally cut flowers, are produced: carnation, gerbera, rose and chrysanthemum. The three most important, commonly occurring pests are Trialeurodes vaporariorum, Tetranychus urticae and aphids (Aphis gossypii, Myzus persicae, A. nasturtii). Polyphagotarsonemus latus, Liriomyza trifolii and Aculops lycopersici caused considerable economic damage during the eighties. However, in the last few years these pests have not been observed in any crops. Two new glasshouse pests have been described from ornamentals during the last 2 years in Hungary: Frankliniella occidentalis and Bemisia tabaci. Their accidental appearance in vegetable crops could lead to direct economic loss, besides endangering biological control systems.

Biological control of pests in Swedish pot plant production

Biological control of glasshouse pests is nowadays an important factor in the production of pot plants in Sweden. During 1990, more than 100 growers applied one or more methods of biocontrol, some only in propagation units but many during the entire production of several crops. Poinsettia is the major crop in this context. Eighty growers were interviewed about their experiences of various biocontrol methods. The use of Neoaplectana carpocapsae against sciarids and Otiorhynchus sulcurus was the most popular and reliable method. Next comes Encarsia formosa against whiteflies. Other methods include Verticillium lecanii against whiteflies and thrips, Aphidius matricariae against aphids, and predatory mites against thrips and spider mites.

Development of glasshouse pests of cucumber under different conditions, in relation to possibilities for their biological control

Experiments were performed under controlled conditions on the development of four cucumber pests (Trialeurodes uaporariorum, Tetranychus urticae, Aphis gossypii and Thrips tabaci). The main variables were temperature, photoperiod and light intensity. The effect of these factors on the natural enemies Encarsia formosa and Amblyseius mckenziei was also assessed. Comparison of the results allows recommendations on manipulation of the glasshouse environment to favour biological control.

New quarantine glasshouse pests in Poland and coloured sticky traps for their monitoring

Trapping methods are being evaluated in Poland in connection with the addition of the following pests to the new Polish Quarantine List: Liriomyza trifolii, L. sativae, L. huidobrensis, Amauromyza maculosa, Thrips palmi, Frankliniella occidentalis, Bemisia tabaci. Variations were observed in the response of F. occidentalis, Trialeurodes vaporariorum and Bradysia spp. to colour, size and method of hanging of the traps. The highest numbers of F. occidentalis were found on blue traps of different shades, of T. vaporuriorum on yellow traps, and of Bradysia on orange and yellow traps.