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 production1

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.     

Occurrence of powdery mildew on aubergine in West Sussex

A powdery mildew ( Erysiphe sp.) was found on the upper surfaces of leaves of a glasshouse-grown aubergine ( Solanum melongena ) crop in West Sussex during Autumn 1992. It could be readily transferred to tomato ( Lycopersicon esculentum ) and tobacco ( Nicotiana tabacum ), but produced restricted growth and sporulation on cucumber ( Cucumis sativus ). Sweet pepper ( Capsicum annuum ), Chinese cabbage ( Brassica campestris var. chinensis ), lettuce ( Lactuca sativa ), chrysanthemum ( Dendranthema x grandiflorum ) and Nicotiana benthamiana did not show symptoms. When transferred to tomato and cucumber, the morphology of aubergine powdery mildew resembled the natural glasshouse powdery mildew on the two crops, respectively, rather than powdery mildew on aubergine. Powdery mildew from naturally infected tomato could infect aubergine directly, and also after one, but not two, generations on cucumber.     

Synergistic effect of Beauveria bassiana and spirodiclofen on the two-spotted spider mite (Tetranychus urticae)

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important pests in agriculture. Due to its short life cycle and high reproductive rate, this pest has become resistant to most acaricides. Therefore, finding alternative control strategies for this damaging pest is necessary. Application of microbiological agents with minimum concentrations of acaricides is a very suitable tactic in integrated pest management. In the present study, lethal effects of a chemical acaricide – spirodiclofen, and an Iranian strain of the entomopathogenic fungus Beauveria bassiana, were evaluated on different life stages of the two-spotted spider mite on two host plants, bean and cucumber. In the next step, compatibility of acaricide with the fungus was studied regarding conidial germination and vegetative growth of the fungus in the presence of different concentrations of the acaricide. Finally, the acaricide at rates of LC₂₅ with the fungus at LC₅₀ were sprayed on adult female mites. The results showed that immature stages of T. urticae were more susceptible to the acaricide whereas the adults were more susceptible to the fungus. Also, mites reared on cucumber were significantly more susceptible to the acaricide and fungus than those reared on bean. Spirodiclofen and the fungus had a synergistic effect; percentage of mortality for fungus infection was 48.6% and 53.5% on bean and cucumber, respectively, while it was 80.6% on bean and 84.5% on cucumber when the mite was sprayed with both the fungus and the acaricide.     

Breeding Plant Varieties Resistant to Pests1)

In The Netherlands at present the research on resistance against pests is aimed at red spider mite in cucumber, glasshouse whitefly in tomato, carrot fly, aphids in lettuce. In addition projects are planned with a view to breeding resistance against Myzus persicae Sulz. in paprika, and aphids in barley. Tolerance can hardly be considered as a type of resistance, since it does not control the parasite population. Non-preference has some advantages, but does not reduce the size of the insect population and causes pests to migrate to other plants and possibly to the neighbours. Antibiosis is the more desirable type of resistance. To prevent it from being broken, antibiosis ought to be based on polygenes. Another method of prevention is to breed multiline varieties. When creating new varieties that possess certain valuable qualities in combination with a resistance based on polygenes, the breeder has to test yearly thousands of plants. Rapid methods for mass-testing for resistance are therefore urgently needed. Breeders have found high-yielding varieties, which help to feed the world population. However, the desired resistance against pests must frequently come from low-yielding varieties. To combine the indispensable high yields with resistance against pests is a time-consuming work. The process will be shortened as better screening methods become available.     

Research on and use of biological methods of pest control in glasshouse crops in Poland1

In 1966/1967, the predatory mite Phytoseiulus persimilis and the hymenopteran parasite Encarsia formosa were introduced into Poland. This introduction led to extensive research on the principles and practical use of biological and integrated programmes of pest control in glasshouse crops. Additional species were later introduced (Macrolophus costalis, Amblyseius mckenziei, Neoseiulus cucumeris, Cycloneda limbifer, Cryptolaemus montrouzieri), and research was also undertaken on local species such as Aphidoletes aphidimyza and Aphidius matricariae. At present, after 25 years of research, modem and effective mass rearing of natural enemies has been organized, and they are applied over 600 ha of glasshouse crops. For correct development of biological methods in glasshouses, new introductions, research, and mass rearing of new species are necessary.     

N-(pyrid-3-yl)thioureas and derivatives as acaricides. II. Quantitative structure-activity relationships and chemodynamic behaviour

The biological activity of a series of N-(pyrid-3-yl)thioureas and -carbodiimides, analogues of the insecticide/acaricide diafenthiuron, towards the carmine spider mite (Tetranychus cinnabarinus Boisd.) and the two-spotted spider mite (T. urticae Koch) was analysed using QSAR methodology. A canonical correlation analysis allowed for the establishment of a prediction model and the identification of outliers within that model. The chemodynamic behaviour of certain compounds in the two series, including these outliers, determined by using photochemical experiments in the laboratory as well as in the glasshouse, was shown to be responsible for anomalous results obtained in the biological tests. It was found from the above study that the biological activity towards both spider mite species is extremely sensitive to the kinetics of formation of the carbodiimides from the corresponding thioureas and to the photostability of the former. The results obtained with a thiourea which underwent no appreciable photochemical transformation into the corresponding carbodiimide supported the hypothesis that the thioureas are also in-vivo propesticides of the acaricidal carbodiimides.     

Effects of far-red light on tritrophic interactions between the two-spotted spider mite (Tetranychus urticae) and the predatory mite Phytoseiulus persimilis on tomato

BACKGROUND

The use of light-emitting diode (LED) lights in horticulture allows growers to adjust the light spectrum to optimize crop production and quality. However, changes in light quality can also influence plant–arthropod interactions, with possible consequences for pest management. The addition of far-red light has been shown to interfere with plant immunity, thereby increasing plant susceptibility to biotic stress and increasing pest performance. Far-red light also influences plant emission of volatile organic compounds (VOCs) and might thus influence tritrophic interactions with biological control agents. We investigated how far-red light influences the VOC-mediated attraction of the predatory mite Phytoseiulus persimilis to tomato plants infested with Tetranychus urticae, and its ability to control T. urticae populations.

RESULTS

Far-red light significantly influences herbivore-induced VOC emissions of tomato plants, characterized by a change in relative abundance of terpenoids, but this did not influence the attraction of P. persimilis to herbivore-induced plants. Supplemental far-red light led to an increased population growth of T. urticae and increased numbers of P. persimilis. This resulted in a stronger suppression of T. urticae populations under supplemental far-red light, to similar T. urticae numbers as in control conditions without supplemental far-red light.

CONCLUSION

We conclude that supplemental far-red light can change herbivore-induced VOC emissions but does not interfere with the attraction of the predator P. persimilis. Moreover, far-red light stimulates biological control of spider mites in glasshouse tomatoes due to increased population build-up of the biocontrol agent. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Methods of controlling Tomato yellow leaf curl virus (TYLCV) and its vector Bemisia tabaci in the Maltese Islands*

Bemisia tabaci and Tomato yellow leaf curl virus (TYLCV) were first observed in Malta in the early 1990s and caused serious damage to glasshouse and outdoor tomato crops. Chemical, physical and biological control methods have been developed, but the effective method has been the use of virus‐tolerant cultivars.     

朱砂叶螨对不同蔬菜寄主的取食选择性

朱砂叶螨Tetranychus cinnabarinus寄主范围广泛,其对不同蔬菜寄主的取食选择性研究很少。本研究采用离体叶碟法和活体寄主法研究了朱砂叶螨在菜豆、茄子、番茄、黄瓜和甜椒等5种蔬菜寄主上的成螨数量、产卵数量、由卵发育至成若螨期的比例及活体寄主上叶螨数量的增长速度。结果表明,朱砂叶螨对供试的不同蔬菜寄主均可取食为害,但其对不同寄主存在取食偏好性。供试的5种寄主植物同时存在时,朱砂叶螨最喜食菜豆,在该寄主上种群发展速度最快,其次是茄子、番茄和黄瓜,在这3种寄主上的取食选择性差异不大,甜椒是该螨相对不喜食的寄主植物,但同样能够使叶螨成功完成其发育历期。离体试验和活体试验结果趋势一致。     

Costs and Benefits of Quarantine Measures against Liriomyza trifolii in Finland1

In order to prevent the entry of Liriomyza trifolii into Finland the importation of rooted chrysanthemum, gerbera, cucumber, tomato and lettuce plants is prohibited, as well as the importation of chrysanthemum cut flowers and leaves of gerbera. Unrooted chrysanthemums and gerberas must be cultivated in quarantine for two weeks before they are approved. During 1982 the total costs of this quarantine survey were 70,000 Fmk. Eradication of the pest has been more expensive; in 1980 its eradication from eight glasshouses caused total costs of 380,000 Fmk to the government, and in 1982 the corresponding figure with four glasshouses was 280,000 Fmk. The range of costs of chemical control in glasshouses growing vegetables and chrysanthemums while « living with >> L. trifolii are estimated to be 0.8–8.8 million Fmk depending on whether 10 or 100 % of the growing area is to be treated. When all the costs caused by exclusion measures are summed (eradication + quarantine) and compared with the costs of « living with >> the pest, the ratio will be 1: 3 to 1: 13 depending on the use of insecticides. The secondary effects of additional use of insecticides on biological control or marketing difficulties because of residues are not included in this comparison. In this case the most economical way of avoiding problems caused by L. trifolii is to invest in pre-entry quarantine measures and prevent its spread into the country.     

Resistance of tomato accessions from the horticulture germplasm bank to red spider mites: exploring mite preference patterns and antixenosis mechanism

The red spider mite Tetranychus evansi can cause up to 90% yield losses to tomato crops. Mechanisms and causes of plant resistance to this pest could contribute to improved planning of plant breeding programs that prevent damage by this pest. It is known that the morphology and chemical compounds present in tomato plants are important to Tetranychus spp. success. This study aims at evaluating the resistance of 84 arbitrarily chosen tomato accessions – obtained from the Horticulture Germplasm of the Universidade Federal de Viçosa (HGB-UFV), Minas Gerais State, Brazil – to T. evansi. We evaluated the number of spider mites per leaf disk, number of trichomes/mm2, and the concentration of hydrocarbons of leaf disk. A significant difference in the number of T. evansi adults/leaf disk was found among accessions. The resistance mechanism of the HGB-UFV accessions was determined to be antixenosis. Accessions 2004, 2098, 2121, and 2100 had higher trichome density and the lowest adult T. evansi per tomato leaf disk. For this reason, these accessions should be chosen as sources of resistance in plant breeding programs. The hydrocarbons C₁₁, C₁₃, and C₂₂ had a negative correlation with T. evansi adults per leaf disk.     

害虫生物防治新技术——载体植物系统

建立一个自我维持并可有效降低害虫种群水平的系统是害虫生物防治长期追求的理想目标。载体植物系统（banker plant system）又称开放式天敌饲养系统,是近年来开发出的一种集保护利用本地天敌、人工繁殖释放天敌以及异地引进天敌等传统技术特点为一体的新型生物防治技术。载体植物（banker plants）、替代食物（alternative foods）和有益生物（beneficial）是该系统的三个基本要素。本文对载体植物和载体植物系统概念、特点以及近年来国际上的研究进展进行了综述,并结合自身的研究实践,举例介绍载体植物系统的应用,以推动国内外对载体植物系统的研究和应用。     

Detection of Ralstonia pseudosolanacearum in drain water based on concentration,enrichment and the use of a duplex TaqMan PCR test

The Ralstonia solanacearum species complex (RSSC) can cause bacterial wilt in a wide variety of plant species, including a number of ornamental glasshouse crops. Recently in Europe, ornamental rose plants for the production of cut flowers and propagation materials have been strongly affected by Ralstonia pseudosolanacearum, phylotype I, biovar 3. To test for the presence of the pathogen in the glasshouse, sampling of water from a drainage gutter or well may be an efficient strategy since it is known that RSSC can be released from infected root systems in the water. A protocol was developed to detect low densities of R. pseudosolanacearum in drain water collected from rose growers. Drain water was filtered through a bacterial filter, the filtrate was collected and target bacteria enriched for 48 h in Semi-selective Medium South Africa (SMSA) broth supplemented with sterilized tomato plant extracts. DNA extracted from the enrichment broth was analysed using a TaqMan test in a duplex format, based on specific egl sequences of RSSC and the use of an extraction and amplification control. The optimized protocol had a detection level of ≤1–10 colony forming units of R. pseudosolanacearum in drain water.     

The tomato leafminer Tuta absoluta (Meyrick) in Tunisia: current status and management strategies

The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) was first identified in the region of Akkouda in October 2008 before it spread to all tomato‐producing areas in Tunisia. The introduction of this pest disturbed existing pest control programmes in greenhouses and open fields, forcing Tunisian growers to use more chemicals to reduce its impact on their crops. A national programme was adopted to control T. absoluta, including cultural practices, the use of pheromones, the installation of insect‐proof screens in greenhouses, and the use of organic insecticides including Bacillus thuringiensis Kurstaki (Bt) and plant extract‐based products. In addition, a few experiments in biological control, using the predatory Mirid Nesidiocoris tenuis Reuter (Heteroptera: Miridae) and the parasitoid wasp Trichogramma cacoeciae Marchal (Hymenoptera: Trichogrammatidae), were conducted in greenhouses and open‐field crops (producing tomatoes for fresh consumption as well as for processing). This paper describes the status of T. absoluta in Tunisia, including data collected from sex pheromone traps installed in six tomato‐producing areas (Takelssa, Korba, Teboulba, Bekalta, Sousse and Kairouan) between 2009 and 2011, and control strategies in greenhouses and open fields.     

Natural compounds in the control of powdery mildew on Cucurbitaceae*

Powdery mildew, caused by Sphaerotheca fuliginea, is a major disease of Cucurbitaceae. The use of natural compounds as alternatives or complements to chemical fungicides would be helpful because the crops require continued prolonged harvesting, during which young unsprayed leaf tissues continuously become available for infection. Several natural compounds were tested on courgette and cucumber plants grown under glasshouse conditions and artificially inoculated with S. fuliginea. Both sodium bicarbonate (0.5%) and mineral oil (1%) proved to be effective in keeping infections under control. These compounds showed a remarkable effectiveness when used in combination. The best results were achieved when the plants were treated after infection but before the disease appeared. Other compounds tested, such as sodium silicate and azadiractin, showed some effectiveness, but satisfactory control of the disease was achieved only at doses causing phytotoxicity in the form of necrotic spots on the leaves, especially on cucumber.     

Occurrence of yellowing viruses (Beet pseudo-yellows virus, Cucurbit yellow stunting disorder virus and Cucurbit aphid-borne yellows virus) affecting cucurbits in Greece

A survey of the incidence of yellowing viruses in Greek glasshouse (and occasional field) cucumber and melon crops was carried out during 2000–03. In most cases disease incidence ranged from 50 to 80%. Simplex RT-PCR was used for the detection of Beet pseudo-yellows virus (BPYV) and Cucurbit yellow stunting disorder virus (CYSDV), and DAS-ELISA for the detection of Cucurbit aphid-borne yellows virus (CABYV). The results showed that BPYV was the predominant virus in cucumber and melon crops, whereas CYSDV, reported for first time in Greece, was isolated only in three regions of southern Greece: Rhodes, Crete and Arkadia. CABYV was detected only in three cucumber glasshouses in Pella (Macedonia). A simplified triplex RT-PCR method using a simple sample-preparation protocol was developed to allow rapid, sensitive and simultaneous detection of the three viruses. Sequence comparisons of the PCR products of BPYV and CYSDV revealed 98·7 and 100% amino acid identity, respectively, with previously reported sequences. The arable weed species Amaranthus retroflexus , Selosia cristata , Sonchus oleraceus and Sonchus sp. were identified as potential BPYV reservoirs.     

应用智利小植绥螨防治温室一串红上二斑叶螨的试验

1983年12月到1984年4月间在北京中山公园温室盆栽花卉(一串红)上成功地进行了释放智利小植绥螨(Phytoseiulus persimilis A.H.)防治二斑叶螨(Tetranychus urticae Koch)的试验。按益、害螨1:10或1:20的比例分别释放两次。每隔7—10天检查一次,释放后3—4周叶螨数显著下降,以后一直维持在大约每叶1头以下。对照区在叶螨高峰期每叶平均126头。施药区虽经6次农药防治,在高峰期平均每叶叶螨112头。释放区花卉色泽和花朵大小也较对照区和施药区的显著为好。     

Effect of variety choice, resistant rootstocks and chitin soil amendments on soil-borne diseases in soil-based, protected tomato production systems

Soil-borne diseases are the most significant crop protection problem in soil-based, low-input and especially organic glasshouse production systems in Europe. While chemical soil disinfestation has been the control method of choice in conventional farming systems, soil steaming has been the main strategy for the control of soil-borne diseases in organic production. Both methods are extremely expensive and have been increasingly restricted for environmental reasons by governments, and integrated and organic farming standard-setting bodies. The use of disease-tolerant varieties, grafting onto resistant rootstocks and chitin soil amendments were evaluated as potential replacements for soil steaming in organic and other low-input tomato production systems. When only Pyrenochaeta lycopersici and/or Meloidogyne spp. were present in soil, grafting and/or chitin soil amendment were found to be as effective in reducing root disease and/or increasing yield as soil steaming, but the efficacy of both treatments was reduced when Verticillum albo-atrum was also present in soil. No additive effects of combining grafting and chitin soil amendments could be detected. A more widespread use of grafting and/or chitin soil amendments may therefore allow significant reductions in the use of steam and chemical soil disinfestation in glasshouse crops. It will also allow integrated and organic farming standard-setting bodies to impose further restrictions on the use of soil disinfestation treatments.     

Parasitoid control of the tomato fruitworm,Helicoverpa armigera,in smallholder farmer fields in Senegal

In Africa, Helicoverpa armigera (Hübner) (Lepidoptera, Noctuidae) is a key pest of cotton and vegetable crops, particularly tomato. Alternatives to insecticides to control this pest are needed such as conservation biological control. However, knowledge on the diversity and ecology of naturally occurring enemies of H. armigera is limited. A two-year field survey was conducted in a set of tomato farmer fields in the main vegetable-growing area in Senegal (Niayes) to assess the spatial and seasonal occurrence of indigenous parasitoids of H. armigera, and to evaluate the effect of insecticide use on biological control efficiency. No parasitoid emerged from H. armigera eggs. Incidence of larval parasitoids was generally moderate (20%) but highly variable (0%–100%) among fields, independently of host abundance, and negatively affected by the number of insecticide applications. Larval parasitism was largely dominated by the larval parasitoid Meteorus laphygmarum Brues (Hymenoptera, Braconidae), but a positive correlation was found between specific richness or Shannon diversity index of the parasitoid community and parasitism rate. This study is a first step toward development of research and extension programs for conservation of natural enemies in the framework of integrated management of the tomato fruitworm in Senegal.