Sprinkler Irrigation as a Management Practice for \u3ci\u3eBemisia Tabaci\u3c/i\u3e (Homoptera: Aleyrodidae) in Cotton Fields

Field experiments were conducted in 1999 and 2000 to investigate the effect of irrigation method on populations of Bemisia tabaci (Gennadius) and natural enemies in cotton fields in Aydın Province, Turkey. Two irrigation methods, sprinkler and border, were studied each year. All plots were irrigated during different phenological periods including initial bloom, boll initiation, 50% boll filling and 5-10% boll opening stages. Irrigation methods and periods significantly affected whitefly populations. Densities of B. tabaci were significantly reduced in sprinkler-irrigated plots compared to border-irrigated plots in 2000 but not in 1999. Irrigation methods did not affect the population of natural enemies. However, significant differences in numbers of natural enemies were observed among irrigation periods. Natural enemies were most abundant during the second irrigation period when whiteflies were also most abundant. These results suggest that sprinkler irrigation may be useful in cotton fields as a management practice for whitefly without reducing natural enemy populations

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

Macroecology of parental care in arthropods: higher mortality risk leads to higher benefits of offspring protection in tropical climates

The intensity of biotic interactions varies around the world, in such a way that mortality risk imposed by natural enemies is usually higher in the tropics. A major role of offspring attendance is protection against natural enemies, so the benefits of this behaviour should be higher in tropical regions. We tested this macroecological prediction with a meta-regression of field experiments in which the mortality of guarded and unguarded broods was compared in arthropods. Mortality of unguarded broods was higher, and parental care was more beneficial, in warmer, less seasonal environments. Moreover, in these same environments, additional lines of defence further reduced offspring mortality, implying that offspring attendance alone is not enough to deter natural enemies in tropical regions. These results help to explain the high frequency of parental care among tropical species and how biotic interactions influence the occurrence of parental care over large geographic scales. Finally, our findings reveal that additional lines of defences – an oftentimes neglected component of parental care – have an important effect on the covariation between the benefits of parental care and the climate-mediated mortality risk imposed by natural enemies

Effect of management spontaneous cover crop on rosy apple aphid, green apple aphid and their natural enemies in an apple organic orchard

Cover crops have been reported as shelters for pest but also for natural enemies. Nevertheless, there is not agreement about their influence on pest presence on apple trees. An experiment was conducted in 2004-2006 in an IRTA-Estació Experimental de Lleida organic apple orchard located in Les Borges Blanques (Lleida, Spain) in order to evaluate the influence of cover crops on the presence of pest and natural enemies on apple trees. Three cover crops were tested and compared to a bare soil: (1) spontaneous cover crop where Plantago lanceolata L. was the most abundant specie, (2) no-mowed spontaneous cover crop, (3) spontaneous cover crop mowed when weeds were 30 cm tall. Cover crops tested affected neither the presence the rosy apple aphid nor aphid natural enemies. Nevertheless, the green apple aphid was more abundant in bare soil trees than in cover crop trees

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

Bidding among friends and enemies

We consider an auction setting in which bidders, even if they fail to obtain the good, care about the price paid by the winner. We study the impact of these price externalities on the first-price auction and the second-price auction in a symmetric information framework. We establish a distinction between price externalities that do not depend on the identity of the winner and price externalities that depend on the identity of the winner. We prove that the outcome of the first-price auction is not affected by the first type of price externalities while the outcome of the second-price auction is. In contrast, the second type of price externalities affects the outcome of both auction formats. In any case, in comparison with the first-price auction, the second-price auction exacerbates the effects of price externalities whatever their types are. The two auction formats are generically not equivalent

Natural Enemies of Alfalfa Weevil, \u3ci\u3eHypera Postica\u3c/i\u3e (Coleoptera: Curculionidae), in Minnesota

Alfalfa weevil, Hypera postica, is present throughout Minnesota. How- ever, economically damaging populations seldom occur, due to a combination of natural enemies and adverse climatic conditions. Five natural enemies of alfalfa weevil were found in Minnesota. Microctonus aethiopoides (Hymenoptera: Braconidae), a parasitoid of adults, was recovered from 43 of 65 counties surveyed during 1984 and 1985. Tetrastichus incertus (Hymenoptera: Eulophidae) and Bathyplectes curculionis (Hymenoptera: Ichneumonidae), para­sitoids of larvae, were each recovered from 13 of 15 counties surveyed during 1991-1993. Bathyplectes anurus, another parasitoid of larvae, was recovered from one county In 1991, four counties in 1992, and six counties in 1993. Zoophthora phytonomi (Entomophthora: Entomophthoraceae), a pathogen of larvae, was recovered from 14 of 15 counties surveyed in 1991-1993. Winters with low minimum temperatures and little snow cover were detrimental to the weevil. Usually, southeastern Minnesota has milder winters and higher alfalfa weevil populations than other areas of the State. However, even here, because of natural enemies, weevil populations seldom reach economically damaging levels

Functional agro biodiversity in Dutch arable farming: results of a three year pilot

A pilot on 400 ha of Dutch arable farms during 2004-2007 perennial grassy field margins and functional annual flower strips were created on potato and wheat fields. Monitoring information on pests and natural enemies was directly communicated to the farmers to support pest management decisions. Due to the increasing numbers of natural enemies and the gradually reducing peak densities of aphids, the farmers could refrain from insecticide applications against aphids in these crops. The pilot has yielded great public awareness on possibilities for functional agro biodiversity in arable crops

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

Wildflower strips to reduce lepidopteran pests in cabbage crops

Vegetable production systems are highly intensive and the periodic cultivations lead to un-favourable conditions for natural enemies. Using non-crops it is possible to create ecological infra-structure offering suitable food for natural enemies, and shelter from adverse conditions. On four organic farms in Western-Switzerland, we have tested in cabbage crops if wildflower strips are an appropriate tool to reduce lepidopteran pests. Analyses of wildflower strips on parasitism of caterpillars of Pieris rapae and Mamestra brassicae indicated a pest control potential. Grid trial using reared egg batches revealed no significant effect on parasitism of exposed M. brassicae and Plutella xylostella eggs in relation to the distance of the strip