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Sint-Truiden, Belgium

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. Source

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 CropScience
Acta Horticulturae

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. Source

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

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. Source

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

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. Source

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

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. Source

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