The state of commercial augmentative biological control: plenty of natural enemies, but a frustrating lack of uptake

Augmentative biological control concerns the periodical release of natural enemies. In com- mercial augmentative biological control, natural enemies are mass-reared in biofactories for release in large numbers to obtain an immediate control of pests. The history of commercial mass production of natural enemies spans a period of roughly 120 years. It has been a successful, environmentally and eco- nomically sound alternative for chemical pest control in crops like fruit orchards, maize, cotton, sugar cane, soybean, vineyards and greenhouses. Currently, aug- mentative biological control is in a critical phase, even though during the past decades it has moved from a cottage industry to professional production. Many efficient species of natural enemies have been discovered and 230 are commercially available today. The industry developed quality control guidelines, mass production, shipment and release methods as well as adequate guidance for farmers. However, augmentative biological control is applied on a frustratingly small acreage. Trends in research and application are reviewed, causes explaining the limited uptake are discussed and ways to increase application of augmentative biological control are explored

Egg-laying-site preferences of Pterostichus melanarius in mono- and intercrops

Increased vegetational diversity influences the behaviour of carabid beetles by changing plant-related abiotic factors. These abiotic factors (light, humidity and habitat structure) affect the selection of oviposition sites and egg survival of carabid beetles. In a field experiment, more larvae of Pterostichus melanarius (Illiger) (Coleoptera Carabidae) were caught in Brussels sprout intercropped with barley than in Brussels sprout alone. The influence of the presence of living barley and Brussels sprout plants on oviposition was studied in the laboratory. Also, the effects of wet/dry substrate, light/shadowed and structured/unstructured environment on the number of eggs laid were investigated under laboratory conditions. Results indicate a preference for moist, shadowed, structurally complex environments as egg laying sites. This preference results in significantly higher numbers of eggs laid by beetles in barley compared to Brussels sprout. Vegetation characteristics by themselves may influence egg-laying-site preferences, in addition to the availability of prey for adults and larvae in the different cropping systems. Vegetables intercropped with cereals provide a more favourable microclimate for the reproduction of P. melanarius than vegetables grown alon

Life history parameters of Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae) at different environmental conditions on two bean cultivars

Life-history parameters of the greenhouse whitefly Trialeurodes vaporariorum (Westwood), an important pest of bean crops in Colombia, were determined in environmental control chambers on two dry bean (Phaseolus vulgaris) cultivars (cv.). Trialeurodes vaporariorum longevity on cv. Chocho decreased as temperature increased from 22.6 d at 19ºC to 5.9 d at 26ºC. Fecundity was significantly lower at 19ºC (8.6 eggs/female), as compared to 22ºC (32.6 eggs/female) and 26ºC (33.3 eggs/female) on cv. Chocho. Fecundity on cv. ICA-Pijao was much higher (127.2 eggs/female) than on cv. Chocho (32.6 eggs/female) at 19ºC. The intrinsic rate of population increase (rm) was highest at 22ºC (0.061), intermediate at 19ºC (0.044) and lowest at 26ºC (0.035) on cv. Chocho, and was 0.072 on cv. ICA-Pijao at 19ºC. Life history parameters of T. vaporariorum are compared to those of one of its natural enemies, the parasitoid Amitus fuscipennis MacGown & Nebeker. Finally, data are presented on the distribution of the parasitoid related to the altitude for the Valle del Cauca, Colombi

Biological control of pests in protected cultivation: implementation in Latin America and successes in Europe

The area with greenhouse crops is estimated to be around 40,000 hectares in Latin America, of which approximately 60% is occupied with ornamentals. Several pests are responsible for losses in yield or quality of greenhouse crops production and pest control is still mainly by chemicals. However, there are several stimuli for the adoption of biological control strategies as an IPM component, not only for the export market of products, but also for increased use of sustainable plant protection methods as a result of the increased success of this methodology in European countries. In Latin America use of native natural enemies plays an important role in pest control and the procedure for development and implementation for biological control in protected cultivation should, therefore, not be based only on the importation and release of commercialized exotic natural enemies. Biological control can be developed making use of effective native natural enemies, or of those introduced a long time ago, and might be supplemented with exotic natural enemies for those pests where native biological control agents are ineffective. In Brazil, the reason for use of native agents is mainly due to concern about environmental risks of imported natural enemies and also because native or naturalized natural enemies are well adapted to local environmental conditions. In many countries, including Brazil, Colombia, Chile, Ecuador, Peru and Mexico, IPM and biological control programs are commercially used or are implemented in pilot greenhouses. Several successes of biological control programs used in Europe will be illustrated

Assessing risks and benefits of floral supplements in conservation biological control

The use of flowering field margins is often proposed as a method to support biological control in agro-ecosystems. In addition to beneficial insects, many herbivores depend on floral food as well. The indiscriminate use of flowering species in field margins can therefore lead to higher pest numbers. Based on results from field observations and laboratory experiments we assessed risks as well as benefits associated with the provision of nectar plants in field margins, using Brussels sprouts as a model system. Results show that Brussels sprouts bordered by nectar plants suitable for the cabbage white Pieris rapae L., suffered higher infestation levels by this herbivore. In contrast, nectar plants providing accessible nectar for the diamondback moth Plutella xylostella L., did not raise densities of P. xylostella larvae in the Brassica crop. Margins with Anethum graveolens L., selected on the basis of its suitability as nectar plant for parasitoids, significantly increased the number of adult Diadegma semiclausum Hellen in the crop. This didn't translate into enhanced parasitism rates, as parasitism of P. xylostella by D. semiclausum exceeded 65 % in all treatments, irrespective of the plants in the field margin. Our findings emphasize the importance of taking a multitrophic approach when choosing flowering field margin plants for biocontrol or other ecosystem service

Harmonia axyridis: an environmental risk assessment for Northwest Europe

In this paper, we summarize the international situation with respect to environmental risk assessment for biological control agents. Next, we apply a recently designed, comprehensive risk evaluation method consisting of a stepwise procedure to evaluate the environmental risks of Harmonia axyridis in Northwest Europe. This resulted in the very clear conclusion that H. axyridis is a potentially risky species for Northwest Europe, because it is able to establish, it has a very wide host range including species from other insect orders and even beyond the class of Insecta, it may feed on plant materials, it can cover large distances (>50 km per year), it does move into non-target areas, it may attack many non-target species including beneficial insects and insects of conservation concern, its activities have resulted in the reduction of populations of native predators in North America, it is known as a nuisance in North America and recently also in Northwest Europe, and it may develop as a pest of fruit in North America. Considering the H. axyridis case, current knowledge would lead to the conclusion that, although the predator is capable to effectively control several pest species, its risks are manifold and it should, thus, not have been released in Northwest Europe. At the time of the first releases in Nortwest Europe in 1995, the available scientific literature made clear that H. axyridis is a large sized polyphagous predator and has a great reproductive capacity in comparison with other ladybird beetles, and that there was a need to study non-target effects because of its polyphagous behaviour. In retrospect, this information should have been sufficient to reject import and release of this species, but it was apparently ignored by those who considered release of this predator in Northwest Europe. The case of Harmonia releases in Northwest Europe underlines that there is an urgent need for harmonized, world-wide regulation of biological control agents, including an information system on risky natural enemy species

Does Wolbachia infection affect Trichogramma atopovirilia behaviour?

Unisexual Trichogramma forms have attracted much attention due to their potential advantages as biocontrol agents. Fitness studies have been performed and understanding the cost that Wolbachia may inflict on their hosts will help in deciding if Wolbachia infected (unisexual) forms are indeed better than sexual forms when used in biological control programmes. The influence of Wolbachia on the foraging behaviour (including walking activity and speed) of T. atopovirilia is reported in this paper. Temperature strongly affected T. atopovirilia female walking activity, but Wolbachia infected and uninfected females differed in none of the behavioural components that were measured such as walking activity and walking speed. Walking activity was highest at 25 ºC and differed significantly from that at 20 and 15 ºC. Trichogramma wasps were highly affected at 15 ºC. Behaviour analysis with females showed that female wasps spend most of the time on drilling + ovipositing on host eggs followed by host drumming and walking while drumming. The parasitism rate and number of offspring did not differ significantly between infected and cured Trichogramma females. Biological control implications of these findings are discussed

Plagen bestrijden zonder gif

Boeren grijpen meestal naar de gifspuit als zij insecten uit hun gewas willen verdrijven. Al sinds de negentiende eeuw weten we dat ook insecten dat werk kunnen doen. Professor Joop van Lenteren schetst - grotendeels uit eerste hand - de ontwikkeling van de biologische bestrijding in de landbou

Waar komen plagen vandaan?

Het zijn meestal ‘saaie’ gewassen waarin natuurlijke vijanden zich niet prettig voelen. Kortom: de mens organiseert een gigantische picknick voor vegetarische insecten en maakt het juist onaantrekkelijk voor de natuurlijke vijanden van die insecten. Behalve ‘monocultuur’ zijn er nog enkele andere belangrijke oorzaken van plagen. Zo slepen we onze gewassen over de hele wereld. Het lijkt logisch dat je probeert om de plaagsoorten niet mee te slepen. Toch is dat in het verleden vaak gebeurd, toen men simpelweg niet wist waardoor plagen werden veroorzaak