Gerben J. Messelink

• Professor
• Biological Pest Control in Greenhouse Productions Systems senior researcher at Wageningen University & Research

BACKGROUND Multispecies natural enemy assemblages may be more successful in suppressing herbivorous pests compared to low‐diversity communities, especially when natural enemies complement each other regarding the niches they exploit. Orius predatory bugs are omnivorous biological control agents used in horticulture, and are widely associated with t...

Biological control of invasive thrips is a challenge in many agricultural systems, partly because of a lack of knowledge about their life cycle and interactions with their environment. Thrips parvispinus Karny (Thysanoptera: Thripidae) is an invasive species causing damage to many crops worldwide and on which our knowledge is still limited. We stud...

Oviposition preferences of plant‐feeding predators remain a complex topic, as such omnivores choose oviposition sites by assessing both plant characteristics and the quality and quantity of nearby animal food sources. Orius predators are omnivores that oviposit endophytically, thus plant characteristics play an important role in their oviposition c...

Thrips of the subtropical genus Scirtothrips are emerging as important pests in several crops. Scirtothrips dorsalis has been increasingly invading new areas outside of its native region of South and East Asia causing economic damage to several crops. Scirtothrips inermis is another polyphagous species with worldwide distribution. Both species are...

Predation or kill rate of biological control agents is often used as a proxy to evaluate the efficacy of different species of natural enemies and under different conditions. For generalist predators and many egg parasitoids, eggs of the Mediterranean flour moth Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) are used as factitious prey or hos...

Larvae of many hoverfly species (Diptera: Syrphidae) are efficient aphid predators, while the adults feed on pollen and nectar. Strawberry crops can be infested by several aphid species, such as the strawberry aphid Chaetosiphon fragaefolii (Cockerell) and the potato aphid Macrosiphum euphorbiae (Thomas), both of which can cause economic damage. Pr...

In the Netherlands, areas surrounding glasshouses are normally uniform and simple in habitat structure, usually comprising of short grass grazed by animals or frequently mowed, fences and canals separating properties. This homogeneous habitat provides little support for spontaneously occurring natural enemies that could enter greenhouses to provide...

Interest in the use of microbial and invertebrate biological control agents (BCAs) in food and agriculture is increasing. Growing concerns about the impact of pesticide use on biodiversity and human health – and increasing demand for products from biodiversity-friendly production systems, including organic systems – have led to growing interest in...

The success of biological control programmes often depends on establishment of natural enemies in or around the crop. An emerging strategy that aims to improve establishment is through the provision of niches that act as shelters. These shelters can enhance the natural enemies’ effectiveness by providing: a suitable microclimate; protection against...

The European tarnished plant bug, Lygus rugulipennis Poppius, is considered a major pest in chrysanthemum nurseries in The Netherlands. Adults puncture plant's apical meristem, after which the growing point splits and growth is inhibited. Flower buds and flowers can also be severely damaged. Both types of damage result in economic losses for grower...

The generalist predatory mite Amblyseius swirskii is a widely used natural enemy of phytophagous pests. Due to the negative effects of conventional pesticides on non-target organisms, the development of selective natural and eco-friendly pesticides, such as essential plant oils, are useful pest control tools to use in synergy with biological contro...

Biological pest control is becoming increasingly important for sustainable agriculture. Although many species of natural enemies are already being used commercially, efficient biological control of various pests is still lacking, and there is a need for more biocontrol agents. In this review, we focus on predatory soil mites, their role as natural...

It has become clear that omnivorous predators can induce plant defences that affect the performance and host plant choice of herbivores. They are also known to induce the production of plant volatiles that can affect the behaviour of herbivores searching for plants. These volatiles may also affect the searching behaviour of other predators, which w...

Several biological control agents of the hemipteran insect families Miridae, Anthocoridae and Pentatomidae, as well as mites of the family Phytoseiidae are known as zoophytophagous predators, a subset of omnivores, which are primarily predaceous but also feed on plants. It has been recently demonstrated that zoophytophagous predators are capable of...

Thrips (Thysanoptera: Thripidae) are major pests in horticulture worldwide. Longstanding biological control strategies that have been developed for flower thrips such as Frankliniella occidentalis (Pergande) are being disrupted by the recent introduction of leaf-inhabiting thrips such as Echinothrips americanus Morgan and Thrips setosus Moulton in...

Generalist predators are increasingly used in biological pest control for greenhouse crops, as they control multiple pests and persist in crops even when prey is scarce. However, some of these predators may cause plant damage due to their omnivorous feeding behaviour. In many European regions, the omnivorous predator Nesidiocoris tenuis (Reuter) (H...

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), has invaded most Afro-Eurasian countries and is threatening worldwide tomato production. Various strategies have been developed and implemented to manage this pest. Here, we present a timely review on the up-to-date development and practical implementation of int...

Blattisocius mali (Oudemans) is a candidate predatory mite on some astigmatid mite pests like Tyrophagus putrescentiae (Schrank). In current study, life table parameters of B. mali were comparatively evaluated when fed on mixed life stages, frozen (one day at -20°C) and cold stored (90 days at -20°C and 4°C) eggs of T. putrescentiae. The highest an...

The predatory mite Amblyseius swirskii is widely used natural enemy of phytophagous pests. Due to negative effects of conventional pesticides on non-target organism, the development of selective natural and eco-friendly pesticides such as essential plant oils are a useful pest control tool to use in synergy with biological control agents. Essential...

One of the ecosystem services of biodiversity is the contribution to pest control through conservation and stimulation of natural enemies. However, whether plant diversity around greenhouses is beneficial or a potential risk is heavily debated. In this review, we argue that most greenhouse pests in temperate climates are of exotic origin and infest...

Astigmatid mites can be used as prey for mass rearing of phytoseiid predators, but also as a supplemental food source to support predator populations in crops. Here we evaluated the potential of six species of astigmatid mites (living or frozen) as alternative food for the predatory mite Amblyseius swirskii Athias-Henriot in greenhouse crops. All p...

Astigmatid mites can be used as prey for mass rearing of phytoseiid predators, but also as a supplemental food source to support predator populations in crops. Here we evaluated the potential of six species of astigmatid mites (living or frozen) as alternative food for the predatory mite Amblyseius swirskii Athias-Henriot in greenhouse crops. All p...

Generalist predators belonging to Dicyphini (Hemiptera: Miridae) play an important role in pest control in vegetable crops. Temperature is one the most important factors affecting their efficacy as biological control agents (BCAs) and a better understanding of temperature effects can help to select the best performing species for certain climatic c...

Several cucurbits species are cultivated in greenhouses worldwide. The most important genera are (1) Cucurbita, which includes squash, pumpkin, zucchini and gourds, (2) Citrullus, which includes watermelon and (3) Cucumis, which includes cucumber and various melons. Pests and diseases affecting cucurbit crops can vary considerably in relation to ge...

Sweet pepper is an important greenhouse vegetable crop and highly attractive to multiple pest and pathogen species. The main pests and diseases detrimental to pepper crops in various parts of the globe are reported here, along with the most effective or sustainable control strategies currently applied to manage them. Biological control of the main...

Astigmatid mites have potential as supplementary prey items to support generalist predator populations in crops. However, applying living prey mites has some disadvantages; if not predated they have the potential to cause crop damage and allergies. In this study, we evaluated various diets based on the astigmatid mite Tyrophagous putrescentiae (Sch...

Dicyphus bolivari Lindberg and Dicyphus errans (Wolff) (Hemiptera: Miridae) are naturally widespread in many crops with low-pesticide pressure, where they prey upon several arthropods, including the tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). However, their efficacy as biological control agents (BCAs) of this pest needs furth...

Mirid predators, a special group of plant-feeding omnivorous predators, have become important biological control agents for pest control in greenhouse cropping systems. Their efficacy and behavior may potentially be affected by microorganisms that induce plant defenses or change plant quality. Here we studied the interaction between a root restrict...

Plant feeding by omnivorous predators can induce plant defences, which decreases the performance of herbivores and influence behaviour of other predators. However, it is not known what are the consequences of this feeding for the plant and how this, in turn, affects the omnivore. We therefore investigated the effects of plant feeding by the omnivor...

Herbivorous arthropods use various cues to choose suitable host plants. We investigated whether three species of herbivores use cues associated with their omnivorous predator Macrolophus pygmaeus to select host plants. Earlier, we found that this omnivore induces plant defences which decreased the performance of two of the herbivores, i.e. the spid...

The poinsettia thrips Echinothrips americanus Morgan is a relatively new pest that has spread rapidly worldwide and causes serious damage in both vegetable and ornamental plants. In this study, we investigated if and how effective this pest can be controlled in gerbera by the omnivorous predator Macrolophus pygmaeus (Rambur). Because herbivores on...

Banker plants can enhance biological pest control by providing both floral resources and appropriate oviposition sites, e.g. through acarodomatia, to predator species. The use of materials mimicking domatia i.e. artificial domatia may be an economically favourable alternative to the use of banker plants bearing domatia. The aim of the present study...

Plants possess various inducible defences that result in synthesis of specialized metabolites in response to herbivory, which can interfere with the performance of herbivores of the same and other species. Much less is known of the effects of plant feeding by omnivores. We found that previous feeding of the omnivorous predator Macrolophus pygmaeus...

Unfortunately, the citation of one of the papers was published erroneously in the original version and corrected here by this Erratum. The original article was corrected.

The poinsettia thrips, Echinothrips americanus Morgan, is an upcoming pest in greenhouse crops, causing serious damage in various vegetable and ornamental crops through extensive foliage feeding. We assessed which stages of E. americanus are attacked and killed by the phytoseiid predatory mites Amblyseius swirskii (Athias-Henriot), Amblydromalus li...

NL De citruswolluis, Panococcus citri, is een hardnekkige en toenemende plaag in de sierteelt onder glas. In dit onderzoek is gekeken of de bestrijding van wolluis met sluipwespen verbeterd kan worden door de levensduur te verlengen met suikers. Het bijvoeren van sluipwespen met suikers (een mix van glucose, sucrose en fructose) verlengde de levens...

Biological control is an important ecosystem service delivered by natural enemies. Together with breeding for plant defence, it constitutes one of the most promising alternatives to pesticides for controlling herbivores in sustainable crop production. Especially induced plant defences may be promising targets in plant breeding for resistance agains...

As every grower knows, thrips are a huge problem in ornamentals grown under glass. The usual suspect is the Californian thrips, a species with a strong preference for flowers. But in recent years another polyphagous thrips has been increasingly raising its head: Echinothrips americanus. Without timely intervention, this typical leaf-dwelling thrips...

Supplying predators with alternative food can have short-term positive effects on prey densities through predator satiation (functional response) and long-term negative effects through increases of predator populations (numerical response). In biological control, alternative food sources for predators are normally supplied on the crop plants; using...

The role of natural enemy diversity in biological pest control has been debated in many studies, and understanding how interactions amongst predators and parasitoids affect herbivore populations is crucial for pest management. In this study, we assessed the individual and combined use of two species of natural enemies, the parasitoid Aphidius ervi...

Biological pest control with mass-produced arthropod natural enemies is well developed in greenhouse crops and has often resulted in the evolution of complex ecosystems with persistent populations of multiple arthropod natural enemy species. However, there are cases where arthropod natural enemies are either not effective enough, not available, or...

The diversity of prey and food sources in crops has a major effect on biological pest control by generalist predators. In this study, we tested if and how supplemental prey or food affects the control of the citrus mealybug Planococcus citri (Risso) by larvae of the green lacewing Chrysoperla lucasina (Lacroix). The larvae of this predator are the...

Omnivores are consumers that feed on both animals and plants. Many important biological control agents (BCAs) are true omnivores feeding on the same host plant of their prey. A major benefit of omnivores is their ability to establish on crops early in the growing season when prey is scarce or absent by feeding on plant provided food sources, such a...

Augmentative biological control has been applied successfully in greenhouse crops for decades. However, still many problems with pest control exist because the natural enemy species used are insufficiently effective or considered as too expensive and for some pests, natural enemies are simple not available. Moreover, new pests continue to emerge th...

Dat trips een enorm probleem is in de sierteelt onder glas is geen nieuws meer. In de meeste gevallen gaat het dan om de Californische trips, een soort met een sterke voorkeur voor bloemen. De laatste jaren duikt er steeds vaker een andere polyfage trips op, de Echinothrips americanus. Deze typische bladbewonende trips kan in sierteeltgewassen zoal...

Fungi belonging to Order Entomophthorales are considered the major pathogen of aphids in natural ecosystems and also in agroecosystems. They are known to cause large scale epizootics, but none of the species of this order have been developed as commercial biological control products. They could be one of the best candidates for controlling aphids i...

Wol-, en schildluis zijn een toenemend probleem in de sierteelt onder glas. Niet alleen het aantal bedrijven met besmetting neemt toe, ook de bestrijding wordt steeds moeilijker. In dit rapport wordt verslag gedaan van verschillende onderzoeksactiviteiten die gericht waren op de bestrijding en detectie van wol- en schildluis. Al het onderzoek met w...

In dit onderzoek is gekeken naar nieuwe mogelijkheden voor bestrijding van wittevlieg in de sierteelt onder glas met omnivore roofwantsen en geuren. Naast de bekende Macrolophus pygmaeus zijn voor deze studie 4 nieuwe soorten roofwantsen verzameld, namelijk Dicyphus errans, Dicyphus eckerleini, Dicyphus maroccanus en Dicyphus tamaninii. Deze zijn b...

Omnivore roofwantsen voeden zich zowel met prooien (plagen) als plantmateriaal. Hierdoor zijn zij in principe inzetbaar wanneer er nog géén plagen aanwezig zijn in het gewas. Wageningen UR Glastuinbouw onderzocht welke omnivore roofwantsen perspectief bieden tegen wittevlieg in de gerberateelt. De bestrijdingsresultaten waren bemoedigend, maar in e...

Understanding how arthropod pests and their natural enemies interact in complex agro-ecosystems is essential for pest management programs. Theory predicts that prey sharing a predator, such as a biological control agent, can indirectly reduce each other's density at equilibrium (apparent competition). From this premise, we (i) discuss the complexit...

Supplemental food sources to support natural enemies in crops are increasingly being tested and used. This is particularly interesting for generalist predators that can reproduce on these food sources. However, a potential risk for pest control could occur when herbivores also benefit from supplemental food sources. In order to optimize biological...

The citrus mealybug Planococcus citri (Risso) is a major pest species in ornamental crops in greenhouses. The decreased use of broad-spectrum pesticides seems to be related to an increase of mealybug infested greenhouses. Biological control with specific parasitoids and predatory beetles is not always effective and often considered as too expensive...

Although many pest species can be controlled successfully with natural enemies (NEs) in greenhouse crops, damage caused by a few persistent pests can still not be reduced sufficiently through the use of NEs alone. Moreover, new pests continue to emerge either through the invasion of exotic species (global trade, global warming), or because less and...

The efficacy of twenty-two strains of entomopatogenic fungi, isolated from natural outbreaks and also from commercial products (Lecanicillium (Verticillium) lecanii (Zimm.) Zare & Gams, Lecanicillium longisporum (Petch) Zare & W. Gams, Beauveria bassiana (Bals.-Criv.) Vuill, Metarhizium brunneum (anisopliae) (Metschn.) Sorokin, Isaria fumosorosea W...

Zoophytophagous predators of the family Miridae (Heteroptera), which feed both on plant and prey, often maintain a close relationship with certain host plants. In this study, we aimed to select a suitable mirid predatory bug for aphid control in sweet pepper. Four species were compared: Macrolophus pygmaeus (Rambur), Dicyphus errans (Wolff), Dicyph...

Biological pest control in greenhouse crops is usually based on periodical releases of mass-produced natural enemies, and this method has been successfully applied for decades. However, in some cases there are shortcomings in pest control efficacy, which often can be attributed to the poor establishment of natural enemies. Their establishment and p...

De citruswolluis, Planococcus citri, is een hardnekkige en toenemende plaag in de sierteelt onder glas. In dit onderzoek is gekeken of de bestrijding van wolluis met sluipwespen verbeterd kan worden door de levensduur te verlengen met suikers. Het bijvoeren van sluipwespen met suikers (een mix van glucose, sucrose en fructose) verlengde de levensdu...

Direct of indirect kunnen endofyten de plantgezondheid en de groei van een gewas gunstig beïnvloeden. Deze bacteriën en schimmels zonder pathogene werking hebben dat al in een aantal gevallen laten zien. Meer onderzoek is nodig om hun precieze werking te achterhalen. De perspectieven kunnen echter groot zijn.

De wolluis is een oud, maar toenemend probleem in rozen en potplanten. Wie het beestje eenmaal op het bedrijf heeft, komt er moeilijk vanaf. Onderzoekers zetten in op een beter werkend systeem om de wolluis op een geïntegreerde manier te kunnen bestrijden.

Bestrijding van plagen wordt soms geholpen door spontaan optredende natuurlijke vijanden. Bij veel grondgebonden teelten komen spontaan roofvliegen en roofkevers voor. Dit onderzoek is gekeken wat de effecten van deze bestrijders op trips in chrysant zijn en hoe ze gestimuleerd kunnen worden. Bij de roofvlieg Coenosia attenuata werd slechts een lic...

Roofmijten van de familie Phytoseiidae zijn in veel gewassen van enorm belang voor de biologische plaagbestrijding van trips, witte vlieg en spint in de glastuinbouw. Inmiddels zijn er 9 soorten commercieel beschikbaar. Het doel van dit onderzoek was om de invloed van het gewas, klimaat en licht op biologische bestrijding met roofmijten op een rij...

Californische trips, Frankliniella occidentalis, is een groot probleem in de sierteelt onder glas. In dit rapport zijn de resultaten weergeven van onderzoek aan toplagen voor roofmijten, bankerplanten voor Orius en een “Lure & infect-systeem” voor volwassen tripsen. Toplagen van een mix van bark, zemelen en gist verhoogden populatiedichtheden van r...

Varenrouwmuggen zijn voor potplantentelers en plantenkwekers een beruchte plaag. De larven van deze Sciaridae, in de praktijk sciara’s genoemd, doen zich tegoed aan de jonge plantenwortels en richten zo grote schade aan. Eén probaat middel bestaat er niet tegen. “Het is én-én. Ik combineer wel vier maatregelen om ze te voorkomen en bestrijden”, ver...

Generalist predators are often used in biological control programs, although they can be detrimental for pest control through interference with other natural enemies. Here, we assess the effects of generalist natural enemies on the control of two major pest species in sweet pepper: the green peach aphid Myzus persicae (Sulzer) and the western flowe...

Since typically there are many predators feeding on most herbivores in natural communities, understanding multiple predator effects is critical for both community and applied ecology. Experiments of multiple predator effects on prey populations are extremely demanding, as the number of treatments and the amount of labour associated with these exper...

Het doel van dit onderzoek was om maatregelen te vinden waarmee bladluis in paprika via de plant geremd kan worden. Hoewel er in de literatuur duidelijke aanwijzingen zijn dat de plantweerbaarheid verhoogd kan worden, is dit niet naar voren gekomen in dit onderzoek. Een verhoogde kaliumgift, wormenhumus en plantversterkers op basis van huminezuren...

De Californische trips, Frankliniella occidentalis is een moeilijk te bestrijden plaag in de chrysantenteelt. Dit onderzoek richtte zich op de verbetering van biologische bestrijding met roofmijten en roofwantsen. In een kasproef met 6 opeenvolgende teelten is de bestrijding van trips gevolgd bij 7 soorten roofmijten (phytoseiiden). Van deze soorte...

De Californische trips, Frankliniella occidentalis , is een van de grootste problemen in de sierteelt onder glas. Vanwege de sierwaarde van bloemen en potplanten worden maar zeer lage dichtheden van trips getolereerd. Dit maakt de biologische bestrijding erg lastig omdat de effecten hiervan vaak onvoldoende zijn om deze zeer lage tripsniveaus te ha...

De bestrijding van ziekten en plagen in roos is uitermate complex. Op veel bedrijven zijn er bijna continu verschillende plagen en ziekten aanwezig waar moeilijk van af te komen is. Het daarom noodzakelijk om het totale complex van gewas, ziekten, plagen en natuurlijke vijanden als één dynamisch ecosysteem te zien waarin alles direct of indirect op...

De sector is op zoek naar nieuwe gewas bescherming zoals “weerbaar telen”. Hierbij wordt gestuurd op een ziekte- en plaag onderdrukking via het substraat en op een sterke- en productie verhogende plant. Er werden een tiental concepten onderzocht op fytotoxicit eit. De keuze van de concepten werd gebaseerd op beschikbaarheid van bouwstenen, gebruik...

1. Indirect interactions between populations of different prey species mediated by a shared predator population are known to affect prey dynamics. 2. Depending on the temporal and spatial scale, these indirect interactions may result in positive (apparent mutualism), neutral or negative effects (apparent competition) of the prey on each other's den...

Biologische bestrijding van plagen in kassen was lange tijd voornamelijk gericht op specialistische natuurlijke vijanden die sterk zijn aangepast aan hun prooi. Gerben Messelink onderzocht de rol van generalistische predatoren bij de bestrijding van meerdere plagen in de teelt van vruchtgroenten in kassen. Uit zijn resultaten blijkt dat spintmijten...

Referaat Biologische bestrijding van bladluis in paprika is zeer lastig en kostbaar, waardoor de bestrijding in de gangbare teelt nog sterk leunt op inzet van insecticiden. De wens is om minder afhankelijk te zijn van deze middelen, omdat ze een risico vormen voor vervuiling van het oppervlaktewater en overschrijding van residu-eisen van supermarkt...

Doel van het onderzoek was om in kaart te brengen wat de effecten zijn van veranderde klimaatfactoren (vochtdeficit en CO2) op de weerstand van de plant en het teeltsysteem. Hogere CO2-doseringen of vochtniveaus hebben een sterke invloed op de plaagbestrijding. Deels door directe effecten op biologische bestrijders en deels door effecten op de plan...

Referaat In twee kassen met een aubergineteelt is gevolgd hoe biologische bestrijders zich vestigen in het gewas en hoe de plagen zich ontwikkelen. Het uitgangspunt daarbij was om alle plagen zolang mogelijk biologisch te bestrijden. De roofwantsen Orius majusculus en Macrolophus pygmaeus (= caliginosus) en 3 soorten roofmijten, Amblyseius swirskii...

De californische trips, Frankliniella occidentalis , is een groot knelpunt in de teelt van chrysant. In dit onderzoek is beoor-deeld in hoeverre de verschillende tripsstadia (larven poppen en adulten) vatbaar zijn voor de entomopathogene schim - mels Beauveria bassiana (Botanigard®), Metarhizium anisopliae (BIO 1020®), Lecanicillium lecanii (Mycota...

Wageningen UR Glastuinbouw is het afgelopen jaar de uitdaging aangegaan om alle optredende plagen in aubergine maximaal biologisch te bestrijden. In twee afdelingen werd gevarieerd met een preventieve inzet van twee soorten roofwantsen en drie soorten roofmijten. De roofmijt Amblyseius montdorensis vestigde zich opvallend goed en verdrong uiteindel...

Met het doseren van CO2 vanuit WKK-installaties in kassen komt altijd een laag percentage rookgassen mee. De laatste jaren is er veel aandacht geweest voor de mogelijke negatieve effecten van deze rookgassen op gewassen. De effecten op andere organismen, zoals plantpathogenen, plagen en natuurlijke vijanden zijn onbekend. Wageningen UR Glastuinbouw...

Doel van dit project is om de belangrijkste basiseigenschappen van generalistische roofmijten in kaart te brengen, om daarmee een beter advies te kunnen geven over de inzet van roofmijten in o.a. de teelt van potplanten. Gestart wordt met een literatuurstudie gevolgd door laboratoriumtesten met 6 soorten roofmijten. Deze publicatie beschrijft de li...

Referaat Sluipwespen worden door veel biologische paprikatelers wekelijks preventief ingezet, om zo snel mogelijk bladluishaarden te laten parasiteren. Dit onderzoek heeft laten zien dat de levensduur van sluipwespen met zo’n 6 dagen verlengt kan worden door ze te voorzien van suikers. Zonder deze suikers zijn de meeste wespen na 6-7 dagen al dood....

Biological control of different species of pest with various species of generalist predators can potentially disrupt the control of pests through predator-predator interactions. We evaluate the impact of three species of generalist predatory mites on the biological control of green peach aphids, Myzus persicae (Sulzer) with the aphidophagous gall m...

In the banker plant method, long-lasting rearing units for beneficials are created in the crop by distributing plants infested with herbivores or carrying other food items, such as pollen. The method has been widely investigated over many years and used to aid establishment, development and dispersal of beneficial organisms employed in biological c...

Rouwmuggen zijn zeer algemeen in kassen, en meestal talrijker dan de typische plaag-insecten. De meeste soorten voeden zich met schimmels en met organisch materiaal, en zijn onschadelijke voor planten. Enkele soorten kunnen schadelijk zijn in zaaibedden, aan stekmateriaal en aan jonge planten. Veel breedwerkende insecticiden hebben een effect op de...

Working Group “Integrated Control in Protected crops, Temperate Climate”. Preceedings of the Meeting at Sutton Scotney (United Kingdom), 18 – 22 September, 2011. Editor: Irene Vänninen. ISBN 978-92-9067-245-6 [VIII + 198 pp.].

Residuvrij telen is een wens van een steeds grotere groep telers. Het realiseren daarvan is voor sommige gewassen, zoals paprika, verre van eenvoudig. In de strijd tegen bladluis boekt Wageningen UR goede resultaten met nieuwe biologische bestrijders en generalistische roofwantsen, maar een volledige biologische bestrijding is nog erg duur. Een sys...

The parasitoid Aphidius gifuensis is able to parasitize both the green peach aphid Myzus persicae and the foxglove aphid Aulacorthum solani in sweet pepper. In a greenhouse experiment we showed that rates of parasitism on green peach aphids alone were equal to the commonly used Aphidius colemani, but lower than with Aphidius matricariae. Foxglove a...