Sint-Truiden, Belgium
Sint-Truiden, Belgium
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Moerkens R.,University of Antwerp | Leirs H.,University of Antwerp | Leirs H.,University of Aarhus | Peusens G.,Pcfruit | And 3 more authors.
Journal of Applied Entomology | Year: 2012

Beneficial arthropods are often used for suppressing specific pest outbreaks in agricultural crop systems. The European earwig, Forficula auricularia L., (Dermaptera: Forficulidae), is an important natural enemy in fruit orchards. Recently, ecological studies were published describing earwig dispersal and survival during summer, hereby revealing clear differences between populations with a single brood (SBP) and two broods a year (DBP). In this article, we will describe three potential mortality factors of earwigs during the underground winter period, namely cold temperatures, parasitoids and soil tillage. This knowledge is essential for making efficient management strategies for increasing earwig abundance in fruit orchards. The effect of cold temperatures was checked during a 3-year semi-field experiment. Parasitism rates of Triarthria spp. (Fallén) and Ocytata pallipes (Fallén) (Diptera: Tachinidae) were obtained in a rearing experiment. The negative effect of soil tillage on the survival of earwigs nests was checked in a field experiment covering a 4-year time period. A strong, negative relation between temperature [cooling day degrees (CDD)] and survival of female and male earwigs during winter was found. Male earwigs of SBP died very quickly, mimicking natural conditions. Between 60% and 90% of females do not survive winter. Survival of females in DBP was higher than in SBP. Parasitism rates vary a lot between species, generation, year and location (0-20%). During winter, we found a maximum mortality of 13%. There is a clear trend that soil tillage can reduce the number of nymphs in spring and summer by 50%. Implications for biocontrol are the following: (i) mortality owing to temperature can be predicted using CDD and if necessary preventive management actions can be undertaken to control pests; (ii) parasitism rates are negligible compared to high impact of temperature; and (iii) soil tillage can be timed more accurately using a recently developed day degree model. © 2011 Blackwell Verlag, GmbH.

Moerkens R.,University of Antwerp | Gobin B.,Pcfruit | Peusens G.,Pcfruit | Helsen H.,Applied Plant Research | And 4 more authors.
Agricultural and Forest Entomology | Year: 2011

1 Phenological day degree models are often used as warning systems for the emergence of arthropod pests in agricultural crops or the occurrence of natural enemies of the pest species. In the present study, we report on a case study of the European earwig Forficula auricularia L., which is an important natural enemy in pipfruit orchards, and describe how such a day degree model can be used to avoid negative effects of crucial orchard management, such as spray applications and soil tillage. A precise timing of these interventions in relation to the phenology of natural enemies will enhance biocontrol. 2 Earwig population dynamics are characterized by single- and double-brood populations, each with specific biological characteristics. 3 A day degree model capable of predicting the phenology of local earwig populations of both population types was developed. The model was checked for accuracy by comparing the first field observation dates of various life stages with predicted values using temperature data from the nearest weather station. In addition, variation in development time was assessed using field data. 4 The model was able to make predictions on a global scale. Although single- and double-brood populations differ in phenology, the predictions of first appearance dates were similar. Variation in development time showed that single-brood populations were more synchronized. 5 Our phenological model provides an accurate tool for predicting and simulating earwig population dynamics, as well as for enhancing the biocontrol of pests in pipfruit orchards. © 2011 The Authors. Agricultural and Forest Entomology © 2011 The Royal Entomological Society.

Vrancken K.,Hasselt University | Holtappels M.,Hasselt University | Valcke R.,Hasselt University | Schoofs H.,PCFruit | And 2 more authors.
Acta Horticulturae | Year: 2014

Plants are host to an important amount of infectious diseases caused by a vast array of fungi, bacteria, viruses and nematodes. In great contrast to the mammalian immune system composed of specialized and mobile defense cells such as lymphocytes, plants have to rely on the ability of each cell to recognize a pathogen and the signals emanating from the infection site to generate several defense mechanisms, either in a preformed or an inducible way. Inducible defense responses are triggered when specific elicitor molecules of the pathogen are recognized by plant cell receptors, which will finally result in a wide range of defense responses provoked by the host in order to prevent further spread of the pathogen. The aim of this study was to highlight the diversity of defense mechanisms in rosaceous plants against the fire blight pathogen Erwinia amylovora. © 2014, International Society for Horticultural Science. All rights reserved.

Ghesquiere K.,Hasselt University | Vrancken K.,Hasselt University | Valcke R.,Hasselt University | Schoofs H.,PCFruit | Deckers T.,PCFruit
Acta Horticulturae | Year: 2011

Fire blight is a major threat to pear and apple production caused by the gram negative bacterium Erwinia amylovora. Pear trees were treated three times with metal solutions of Mn or Cu starting at the white bud stage. Subsequently, they were artificially infected with E. amylovora. Infection rates were assessed and ooze formation was monitored. At 7 days after infection, an inhibitory effect of Mn on the rate of infection could be seen. In a second trial, pear trees carrying young fruits were treated three times at 10-day intervals with Cu or Mn solutions. Chlorophyll fluorescence imaging analysis carried out one day post-treatment showed that the metal treatments do not cause phytotoxicity. The unripe fruit were harvested and artificially infected with fire blight. In this trial, a beneficial effect of the metal treatments on the infection rate or the ooze formation could not be demonstrated.

Bangels E.,PCFRUIT | Peusens G.,PCFRUIT | Belien T.,PCFRUIT | Gobin B.,Research Center for Ornamental Plants
Acta Horticulturae | Year: 2011

Pome fruit growers around the world are gradually adopting Integrated Fruit Production (IFP). IFP is defined by the IOBC as the economical production of high quality fruit, giving priority to ecologically safer methods, minimising the undesirable side effects and use of agrochemicals, to enhance the safeguards to the environment and human health. Integrated Pest Management (IPM) is central to IFP and strongly depends on the availability of selective insecticides. Spirotetramat (brand name Movento®) is a very promising active ingredient belonging to the class of tetramic acid derivatives. It has a two-way systemic action, allowing it to move downwards as well as upwards within the plant in the phloem and in the xylem vessels. From 2002 onwards, numerous GEP and non-GEP field trials with this new compound were performed by pcfruit in apple and pear orchards in Belgium. Trials were all executed according to EPPO guidelines. Based on the outcomes of these trials, spirotetramat was proven to be efficient against a broad range of pests. In addition, spirotetramat was shown to have a good safety profile with respect to a range of beneficial arthropods (e.g., Typhlodromus pyri and Anthocoris sp.). Since the withdrawal of a number of plant protection products and limited use of certain broad-spectrum products according to the IFP-guidelines, the control of pest species such as pear sucker (Cacopsylla pyri) and woolly apple aphid (Eriosoma lanigerum) is very complicated at this time. Hence, the introduction of spirotetramat, with good efficacy against several severe pome fruit pests and good beneficial safety, will appreciably strengthen the currently applied IPM control strategies in IFP.

Phytoplasmas are plant pathogenic mollicutes that cause devastating diseases in various crops worldwide. The closely related pome fruit tree phytoplasmas Candidatus Phytoplasma mali and Candidatus Phytoplasma pyri are the causal agents of apple proliferation and pear decline, respectively. They can be transmitted from tree to tree by Psyllidae. As pear suckers (Cacopsylla pyri) are widely considered to be the most important pest in pear orchards, a good control of this insect vector is a key element for limiting the natural spread of pear decline. Efficient control relies on a perfect tuning of treatment schedules, taking into account efficacies of (at preferably) low-impact insecticides and side-(repellent)-effects of alternative products (e.g. kaolin, mineral oils and fungicides), the optimal positioning of these crop protection agents, and the best possible presence of beneficial predators. The department of Zoology of the pcfruit vzw research institute (Belgium) has a long tradition of executing insecticide field trials according to EPPO guidelines. Here, we present an overview of the results of a selection of IPM-compatible insecticides (abamectin, spirotetramat, thiacloprid, spinosad, spirodiclofen), tested in efficacy trials against pear Psylla on different life stages during the last decade. Based on these results and monitoring data of pest and beneficial biology, we additionally propose optimal pear Psylla control schedules which allow to reduce the number of (phytoplasma harbouring) psyllids in integrated systems to a minimum.

Moerkens R.,University of Antwerp | Leirs H.,University of Aarhus | Peusens G.,Pcfruit | Gobin B.,Pcfruit
Entomologia Experimentalis et Applicata | Year: 2010

Quantitative information on dispersal of insects should be taken into consideration for making efficient pest management decisions. Such information was not available for the European earwig, Forficula auricularia L. (Dermaptera: Forficulidae), an important biocontrol agent in fruit orchards. A mark-recapture experiment was carried out in Belgian orchards, where marked earwigs were released at a single point and recaptured after 1 month. Dispersal from this release point was analysed using an analytical formula of a simple diffusion model with disappearance (e.g., as a result of death) derived by Turchin & Thoeny (1993; Quantifying dispersal of southern pine beetles with mark-recapture experiments and a diffusion model. Ecological Applications 3: 187). The cumulative number of recaptured earwigs as a function of the distance of release was used to fit the model and estimate parameters. A derived expression, in terms of these parameters, was used to estimate the frequency distribution of the population, as the radius of a circle enclosing various proportions of the earwigs' dispersal distances. In Belgium, populations of the European earwig can have two life-history strategies, single- (SBP) and double-brood populations (DBP). Therefore, mark-recapture experiments were carried out on both population types. We fitted data from SBP (n = 10) and DBP (n = 16) successfully in both the diffusion model and in an exponential curve. Because of the biological relevance, estimates of the diffusion model were used for calculating the frequency distributions. Males and females dispersed the same distances. No differences were found between orchards with different spatial structures (apple and pear). According to literature data, mobility of earwigs is very low compared with other arthropods, which has consequences for the efficiency of biocontrol interventions, like mass releases of earwigs or the use of hedgerows for the establishment of healthy (source) populations. Quantitative results revealed that earwigs of SBP dispersed four times further than earwigs of double-brood populations. For instance, 95% of the population remained within a radius of 28.6 m in SBP and 7.54 m in DBP. © 2010 The Authors. Journal compilation © 2010 The Netherlands Entomological Society.

PubMed | pcfruit
Type: Journal Article | Journal: Communications in agricultural and applied biological sciences | Year: 2010

Plant protection products are designed to control pests but can have negative side effects on non-target arthropods thus disturbing the important population of natural enemies required for biological control. Although the European earwig, Forficula auricularia L, (Dermaptera: Forficulidae) is not considered to be a key beneficial in pome fruit, it is an important predator of several pests, e.g. woolly apple aphid and pear sucker. The impact of non-selective plant protection products at crucial moments in their (univoltine) life cycle can be of significant relevance compared to insects with numerous generations. Foliar applications in spring when nymphs are migrating into the trees can reduce the number of adults in summer and subsequently affect the population size next year. Multiple and/or combined spraying during summer on adults may have a cumulative effect resulting in less over wintering females which possibly exhibit poor reproductive performance. Previous residual contact bioassays already revealed the harmful side effect of several formulated products on adults. Insects showing sub lethal symptoms recovered partially or died eventually. As spinosad caused significant toxicological effects it was subsequently tested in 3 different dose rates on adults and N4-nymphs. We noticed not only a clear dose-response relationship but N4-nymphs proved to be more susceptible than adults; even a dilution of 1/9-th of the registered dose rate still caused a mortality of 45.5 % after 20 days. Understanding the earwigs population dynamics is essential for efficient practical biocontrol. It proves difficult to increase population levels to sufficient high numbers for optimal pest control. Local biological factors might be limiting. Therefore, we tested two hypotheses that pertain to population limitation: 1. Bird predation during summer, 2. Small mammal nest predation during winter. Enclosure experiments showed no negative bird effect on earwig densities unless large bird flocks inhabited the area. Small mammals did not actively predate the over wintering nests, although other predatory arthropods may be important.

Sirven C.,BCS SA Small Molecule | Latorse M.-P.,BCS SA Small Molecule | Peyrard S.,BCS SA Small Molecule | Deckers T.,Pcfruit | De Maeyer L.,Bayer AG
Acta Horticulturae | Year: 2015

Fosetyl-Al is a well-known anti-oomycetes fungicide with efficacy based on an indirect action as stimulation of the natural plant defenses. Field phenotypic observations in apple, pear and cherry orchards have revealed very positive effect of fosetyl-Al on flowering the year following treatment. An advantageous effect was noticed both on quantity as on the quality of flower buds. Flower cluster of trees treated with Aliette in the previous season had more flowers and a tendency of being surrounded by more well developed rosette leaves. Fosetyl-Al's mode of action analysis was conducted in parallel and independently on the vine-downy mildew patho-system to elucidate the effect as stimulator of natural plant defense. Transcriptomic analysis clearly showed involvement of fosetyl-Al in defense response with genes deregulation in chalcone synthase biosynthetic pathway and in stilbenes accumulation. Those pathways are the most frequently and best characterized defense mechanisms described in vine. Besides that, 3 clusters of genes corresponding to auxine responsive proteins were found slightly up-regulated with fosetyl-Al preventative treatment. Speculation on the role of those genes induced by fosetyl-Al and consequently the input on flowering quality on apples and pears could be discussed.

Belien T.,Pcfruit | Bangels E.,Pcfruit | Peusens G.,Pcfruit | Berkvens N.,Belgium Institute for Agricultural and Fisheries Research | And 2 more authors.
Acta Horticulturae | Year: 2011

Since the withdrawal of certain insecticides and the restricted use of some broad-spectrum plant protection products, the woolly apple aphid (Eriosoma lanigerum) has become one of the most severe pests in apple growing areas across western Europe. Their protective wax coating makes them particularly difficult to control. At present, effective limitation of woolly aphid populations relies on a good synergy between chemical control treatments and biological suppression by parasitoids and predators. Optimal control strategies take advantage of a thorough understanding of the life cycle of woolly apple aphids, the timing of their migration waves and their interaction with the environment. Based on monitoring data and research results (side effects trials, field population dynamics of beneficial arthropods) we here present pest management programs that take profit of a maximal natural regulation of E. lanigerum. In addition, the potential implementation of new alternative biological control methods is discussed.

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