Search

Context: Manipulating crop diversity in the landscape has been suggested as a promising management option to enhance biocontrol but how crop diversity independently of other important aspects of landscape structure affects predator and pest abundances remain largely unexplored. Objectives: Our study assessed the relative and interactive effects of crop composition and configuration on aphids and their generalist predators, i.e. ladybirds, spiders and lacewings. Methods: We sampled arthropods in 47 cotton fields and 21 wheat fields in Hebei, China, located along three landscape gradients: crop diversity (Shannon diversity of crops ranging from 0.27 to 1.32 corresponding to a crop richness varying from 2 to 7 different crops), crop configurational (crop edge density varying from 0.0012 m/ha to 0.066 m/ha) and proportion of semi-natural habitats (varying from 0.5% to 56%). Results: Crop diversity never had any effect on arthropod communities and we found no effect of the proportion of semi-natural habitats on natural enemies' abundances. Aphid abundance was positively correlated with the proportion of semi-natural habitats both in cotton and wheat fields. Lacewing abundance benefited from configurational heterogeneity as abundances increased with crop edge density. Conclusions: Our result provide evidence that crop diversity is probably not the best management option to enhance biocontrol of aphids in Chinese landscapes and confirms that the amount of semi-natural habitats in the landscape is a critical aspect shaping arthropod communities. It also indicates that manipulating crop edge density by promoting agricultural landscapes with small field size for instance can benefit natural enemies of crop pests. [ABSTRACT FROM AUTHOR]

The South American tomato pinworm, Tuta absoluta (Meyrick), is one of the major threats to tomato production. Larvae can cause losses of more than 80% of production. It was officially detected for the first time in West Africa in 2012, in Senegal, and was subsequently reported in most countries in this part of the continent. To identify infested vegetable production areas and determine reservoir plants in Côte d'Ivoire, surveys were carried out and pheromone traps set in the North, South, East, West and Center in the main tomato production areas of the country. The pest was detected in all surveyed areas, with the highest number of males (623 ± 19.5 insects/week) caught by pheromone traps in Bouaké in the Center of Côte d'Ivoire and a highest percentage of infested leaves, 96 ± 2.5%, was obtained in the locality of Agnibilékro in the East of the country. Tuta absoluta attacked all phenological stages of tomato plant in field. Larval mines were observed on the eggplant, Solanum melongena, the black nightshade, Solanum nigrum and the peppers, Capsicum annuum. Apart from tomato, T. absoluta seems to prefer S. melongena (41.64 ± 2.95% of infested leaves/plant; 4.88 ± 0.4 mine/plant) and S. nigrum (36.27 ± 3.42% of infested leaves/plant; 4.26 ± 0.6 mine/plant) more than C. annuum (13.48 ± 2.42% of infested leaves/plant and 1.38 ± 0.18 mine/plant). This study led to understanding that T. absoluta is well established in the main tomato production areas of Côte d'Ivoire, causing damage regardless of plant development stages and is present on other plant species. [ABSTRACT FROM AUTHOR]

In the current paper, we reviewed the use of nanoparticles (NPs) in crop protection, emphasizing the control of pests in the agricultural and urban environment. At the same time, we provide the framework on which the technology of NPs is based and the various categories of NPs that are currently used for pest control. Apart from the use of NPs as carriers of a broad category of active ingredients, including insecticides and pheromones, some NPs can be used successfully as insecticides alone. Moreover, several types of NPs are produced by natural resource-based substances, which make them promising 'green' alternatives to the use of traditional pest control agents. Finally, the potentials in the use of NPs are briefly illustrated and discussed. [ABSTRACT FROM AUTHOR]

Parasitism rates and parasitoid development can be influenced by the species and developmental stage of the host, both of these factors can influence parasitoid performance and fitness. In this study, parasitism rates and developmental parameters were assessed for two widely distributed and commercially available species of aphid parasitoid: Aphidius ervi (Hymenoptera: Braconidae) and Aphelinus abdominalis (Hymenoptera: Aphelinidae). In a first bioassay, parasitism rates and parasitoid development were investigated in different host species. The wasp A. ervi was tested on Macrosiphum euphorbiae, Rhopalosiphum padi, and Myzus persicae (Hemiptera: Aphididae) and A. abdominalis was tested on M. persicae, R. padi, and Rhopalosiphum maidis (Hemiptera: Aphididae). The results indicated that A. ervi had a greater percentage of emergence, higher percentage of parasitized aphids, longer developmental time, and higher proportion of females in M. persicae than in the other hosts. A. abdominalis had a greater percentage of emergence, larger progeny, and shorter developmental time in R. padi than in the other hosts. A second bioassay evaluated the preference of the parasitoids for different instars of their respective optimum host aphids in terms of parasitism and development, as determined in the first bioassay. The results showed that A. ervi produced a greater number of mummies in the fourth instar and in adults of M. persicae. In contrast, A. abdominalis preferred the first instar of R. padi. In conclusion, our results indicate that both parasitoid species exhibit different parasitism parameters depending upon the host species and the host stage. This suggests that these parasitoid species could be potentially complementary on multiple or combined releases of biological control programs. [ABSTRACT FROM AUTHOR]

After its arrival in 2008, the Spotted Wing Drosophila (SWD), Drosophila suzukii, has emerged as a harmful invasive insect pest in North America and Europe. This highly polyphagous pest is a major threat to many economically important fruit crops and is also known to develop on a wide variety of natural host plants. In Asia, Europe and North America, different control measures are applied against SWD, such as chemical, biological, and cultural control. Current controls of SWD rely primarily on the application of insecticides, but cultural management tactics such as sanitation and the use of nets provide a good alternative in some crops. Biological control measures, such as conservation of existing natural enemies in invaded areas, introduction of specialized larval parasitoids from Asia for classical biological control and the use of indigenous parasitoids for augmentative control, are currently being investigated and may become an important management tool in the near future for an area-wide control of SWD. [ABSTRACT FROM AUTHOR]

Plant-insect interactions are strongly modified by environmental factors. This study evaluates the influence of nitrogen fertilisation on the tomato ( Solanum lycopersicum L.) cv. Santa clara and the leafminer ( Tuta absoluta (Meyrick), Lepidoptera: Gelechiidae). Greenhouse-grown tomato plants were fed hydroponically on a complete nutrient solution containing either a high nitrogen concentration ( HN) sustaining maximum growth or a low nitrogen concentration ( LN) limiting plant growth. Insect-free plants were compared with plants attacked by T. absoluta. Seven and 14 days after artificial oviposition leading to efficacious hatching and larvae development, we measured total carbon, nitrogen and soluble protein as well as defence compounds (phenolics, glycoalkaloids, polyphenol oxidase activity) in the HN versus LN plants. Only in the HN treatment did T. absoluta infestation slightly impair leaf growth and induce polyphenol oxidase ( PPO) activity in the foliage. Neither the concentration of phenolic compounds and proteins nor the distribution of nitrogen within the plant was affected by T. absoluta infestation. In contrast, LN nutrition impaired T. absoluta-induced PPO activity. It decreased protein and total nitrogen concentration of plant organs and enhanced the accumulation of constitutive phenolics and tomatine. Moreover, LN nutrition impaired T. absoluta development by notably decreasing pupal weight and lengthening the development period from egg to adult. Adjusting the level of nitrogen nutrition may thus be a means of altering the life cycle of T. absoluta. This study provides a comprehensive dataset concerning interrelated responses of tomato plants and T. absoluta to nitrogen nutrition. [ABSTRACT FROM AUTHOR]

More than six decades after the onset of wide-scale commercial use of synthetic pesticides and more than fifty years after Rachel Carson's Silent Spring, pesticides, particularly insecticides, arguably remain the most influential pest management tool around the globe. Nevertheless, pesticide use is still a controversial issue and is at the regulatory forefront in most countries. The older generation of insecticide groups has been largely replaced by a plethora of novel molecules that exhibit improved human and environmental safety profiles. However, the use of such compounds is guided by their short-term efficacy; the indirect and subtler effects on their target species, namely arthropod pest species, have been neglected. Curiously, comprehensive risk assessments have increasingly explored effects on nontarget species, contrasting with the majority of efforts focused on the target arthropod pest species. The present review mitigates this shortcoming by hierarchically exploring within an ecotoxicology framework applied to integrated pest management the myriad effects of insecticide use on arthropod pest species. [ABSTRACT FROM AUTHOR]

Copyright of EPPO Bulletin is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Insect-proof nets are thought to be effective physical barriers to protect tomato crops against several insect pests, including the invasive tomato pest, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). However, protected tomato crops are frequently infested by this destructive pest, and there is a higher infestation of plants closer to openings in Mediterranean greenhouses, suggesting that immigrating adults can easily walk on these protective materials and find a way to reach the crop. Laboratory bioassays were carried out to characterize the potential toxicity of α-cypermethrin-treated insect-proof nets (Agronet) against T. absoluta adults. The data showed that the net acts mainly through a variety of chronic sublethal effects rather than acute ones. Reduced longevity and, more markedly, a reduced number of laid eggs were observed after the moths were exposed to the treated net over the duration of their lifetimes. A Y-tube experiment showed that the treated net does not affect the T. absoluta olfaction cues for host location. In contrast, when the moths were given the option to choose either the treated or the untreated net in laboratory cages, they significantly preferred the untreated one. The toxicological significance and the functional implications of these subtle effects for the implementation of integrated T. absoluta management strategies are discussed. [ABSTRACT FROM AUTHOR]

Copyright of EPPO Bulletin is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)