•Antifungal power of non-phytotoxic essential oils is useful to control white rot.•Essential oils present positive interaction with synthetic fungicides.•Essential oils can be used to reduce doses of ...chemical pesticides in garlic crops.•Laurus nobilis and Tagetes filifolia essential oils can be used into integrated pest management.
This study was conducted to evaluate essential oils (EOs) and their binary combinations with fungicide iprodione (Ip) as a potential fungicide against Sclerotium cepivorum Berk in order to reduce the amount of pesticide applied in garlic crops. Five essential oils (EOs) from different plants grown in Argentina were studied: Tagetes minuta L. (Su), Tagetes filifolia L. (An), Origanum vulgare L. spp. Vulgare (OCom), Origanum x majoricum (OMen), and Laurus nobilis L. (Ba). The chemical composition of EOs was analyzed by GC–MS. The minimum fungicide concentration (MFC) and minimum inhibitory concentration (MIC) were determined for each compound. A total of 84 combinations of EOs and Ip were assessed looking for synergistic interactions. A phytotoxicity assay was carried out to identify EOs with a potential negative effect on garlic. The effect of EOs, Ip and mixtures on white rot was evaluated in a field study. Fungicide Ip had the best antifungal activity in the in vitro test. OMen and OCom showed high antifungal activity, but also had a strong phytotoxic effect on garlic plants. Su had a moderate antifungal effect with distinguished synergism with Ip, but none can be used due to its phytotoxic effect. An and Ba both had moderate antifungal activity. These EOs had no negative effect on garlic germination and production, being non-phytotoxic for this crop. In this study, the combinations of An and Ba them with Ip have synergistic interactions. Sclerotia density and disease incidence were reduced by these mixtures in a field study. In conclusion, An and Su could be used as natural fungicides to control white rot in garlic, reducing the fungicide dose required. However, future studies are needed to adjust final concentrations to be applied in field crops.
Squash bug, Anasa tristis DeGeer (Hemiptera: Coreidae), is a major pest of squash and pumpkins in the United States. In order to better understand the importance of natural egg parasitism of this ...species in Virginia, we conducted a 2-yr statewide survey. In total, 1,127 squash bug egg masses (∼20,000 total eggs) were sampled from squash and pumpkins from 43 counties in Virginia from 2014 to 2015. Egg masses were brought back to the lab to record levels of squash bug nymphal emergence or adult parasitoid eclosion and identification. Over 50% of the total squash bug eggs collected statewide were parasitized. Gryon pennsylvanicum Ashmead (Hymenoptera: Scelionidae) was the predominant egg parasitoid accounting for over 98% of all parasitoid adults recovered. The only other species emerging from squash bug eggs was Anastatus reduvii Howard (Hymenoptera: Eupelmidae), which is a generalist parasitoid. G. pennsylvanicum was found in 75% of the counties surveyed with the highest levels of parasitism occurring in the Northern, Southwestern Mountain, and Western Piedmont regions of the state and the lowest levels of parasitism occurring in theTidewater region in the southeastern portion of the state. Based on this 2-yr survey, G. pennsylvanicum was determined to be a major natural enemy of squash bug, significantly reducing the number of nymphs that emerge from deposited eggs. Conservation of this natural enemy should therefore be a priority for integrated pest management programs in cucurbits.
Cacopsylla bidens (Šulc,
1907
) is reported for the first time from India. A brief diagnosis, images and comparison with allied species are provided to validate this new faunal record and facilitate ...its prompt identification. Seasonality and some elements of the biology of the pest from the Kashmir valley are also provided.
Pests attacking the ear of sweet corn, such as
Helicoverpa
and
Euxesta
species, cause economic losses for the producer and the processing industry. Feeding on the style-stigmata preventing ...fertilization and on the developing grain and the association with pathogens are the main causes of product depreciation. The traditional control such as spraying with chemicals is not effective, even with several applications directed to the corn ear.
Bacillus thuringiensis
(Bt) corn also does not reach the fly. McPhail traps that have been used to monitor the pest can be a control strategy. This work evaluated the efficiency of food attractants placed inside McPhail traps to remove adult insects, in order to reduce ear damage. Twelve McPhail-type traps were installed in a randomized complete block design containing Bio Anastrepha® alone or combined with different doses of insecticide. Every 10 days, all the captured insects were counted and separated by species and sex. Only
Euxesta eluta
and
Euxesta mazorca
were found. The occurrence of insects was greater in the period between silk emergence and grain filling. The number of females was higher, probably due to the need to feed before oviposition. The number of
E. mazorca
females caught in the treatment containing only Bio Anastrepha® was higher compared with that of others. The mean ear damage was very low, and there was no interaction between the production parameters and the distance between the trap and the harvested plant. In short, the use of McPhail trap containing food attractants may be a viable alternative to control corn silk flies.
The rapid spread of the fall army worm (Spodoptera frugiperda) across sub-Saharan Africa, and now South Asia, has created surprise and distress to the smallholder farmers of both regions who face ...hunger and economic stress because of this pest. There has been high-quality support from the international agricultural information sector, but there has also been advice that may not be applicable to the farming systems of smallholder farmers. That comment arises from lessons learned from involvement with a similar pest outbreak of a related pest species in India starting in the mid-80s. Post-rainy season groundnut (peanut) Arachis hypogaea is a high-value crop in the coastal region of Andhra Pradesh. Changes in the management of tobacco crops to the North of the groundnut belt resulted in invasions of Spodoptera litura. The groundnut farmers responded by applying a wide range of insecticides that did nothing to protect their crops from further defoliation. Scientists from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) initiated research that enriched the knowledge of this crop–pest relationship. For instance, they showed that groundnut plants could withstand close to complete defoliation with little loss in yield. Farmers also learned that the cessation of their insecticide regime allowed natural enemies of the caterpillars to take over the management of the pests. They were showed how to enhance the populations of the coccinellids and the birds that were the key predators. ‘Citizen Scientists’ led this process. Non- and quasi-governmental organizations took over the extension process. They were provided with ongoing personal and technical support, for instance, the provision of definitive facts about the high levels of insecticide resistance, encouraging cultural control techniques, and of exploiting natural enemies, including entomopathogens. The involvement of the ICRISAT team later extended into the groundnut fields of South East Asia.
Plutella xylostella is the main pest of cruciferous crops worldwide. To reduce P. xylostella populations, better integration of natural control and chemical control (dominant tactic used) is needed. ...This work analyzed the compatibility of nine insecticides with the parasitoid Diadegma insulare, outlining them as complementary tools in an integrated pest management strategy. The acute toxicity of spinosad, imidacloprid, indoxacarb, flonicamid, naled, pyridalyl, emamectin benzoate, and spinetoram against the parasitoid was assessed. Residual activity (persistence) was also evaluated over time; the mortality of the parasitoid in contact with leaf tissue of plants treated with insecticides was analyzed. According to the International Organization of Biological Control, all nine insecticides were toxic to D. insulare; the lowest mortality was recorded with spirotetramat (64%) and pyridalyl (48%), while the rest of the insecticides caused 100% mortality at 72 h after application. In terms of persistence, by days 14, 16, 16, 17, 17, 21, and 22 after application, flonicamid, naled, spirotetramat, spinosad, piridalyl, imidacloprid, and indoxacarb caused mortality of less than 25%, respectively, so they were considered harmless (Category 1). Nonetheless, some insecticide toxicity and residual activity must be regarded within integrated pest management programs for conserving the role of D. insulare field populations.
In order to trace the research history of diseases and pests in rubber tree and explore the potential for their natural control, a bibliometric analysis was conducted based on relevant documents ...retrieved from the Clarivate Analytics Web of Science (WoS) core collection SCI-E database. VOSviewer software was utilized to analyze the research distribution, scientific collaboration, knowledge structure, and research frontiers. The results show that annual publications on the diseases and pests of rubber tree have increased rapidly after 2005 after a long period of emergence and fluctuation. A total of 624 relevant publications from 51 countries/regions were identified. China was the most productive country with 152 documents, most of which were related to Colletotrichum leaf disease, powdery mildew, and other emerging diseases of rubber tree. France and Brazil produced rich research to tackle South American leaf blight, and have established a close collaborative relationship. Based on the analysis of themes and trend topics, pathogenicity mechanisms of fungal pathogens and plant defense mechanisms are currently hot topics. By further looking into the research, the defense-related genes of rubber tree and antagonistic mechanisms behind candidate biocontrol agents reveal great potential in developing natural control strategies. This study provides a useful reference about the progress and evolution of research into diseases and pests in rubber tree.
Weeds in coffee crops have diverse ecosystem services, such as sheltering and feeding natural enemies of pest insects. This study aimed to identify the potential of coffee weeds as food and refuge ...for natural enemies in shaded and sun coffee crops. Weeds were sampled in a 100 m transect installed in each type of coffee crop. Malaise traps and sweep-nets were both used to capture insects every 15 days for five months. After identifying the dominant weeds, observations and a direct recollection of insects were carried out at three different hours during three days. Faunistic analyses were performed, as well as the Bray and Curtis similarity analysis and the Student's t test. Emilia sonchifolia, Acmella oppositifolia, Bidens pilosa were predominant in the free exposure sun plantation coffee crops and Commelina diffusa, Salvia palifolia, Stachytarpheta cayennensis in under shade coffee crops. High insect activity was found between 11:30 am-12:00 pm. In these weeds, we found about 15 families, the most important were Formicidae, Braconidae, and Coccinellidae. We concluded that the shaded coffee crops exhibited a natural enemy community similar to that of the sun. Through this exploratory study, we verified that weeds harbor a diversity of natural enemies important to the coffee agroecosystems.
In the absence of antiviral therapy, HIV-1 infection progresses to a wide spectrum of clinical manifestations that are the result of an entangled contribution of host, immune and viral factors. The ...contribution of these factors is not completely established. Several investigations have described the involvement of the immune system in the viral control. In addition, distinct HLA-B alleles, HLA-B27, -B57-58, were associated with infection control. The combination of these elements and antiviral host restriction factors results in different clinical outcomes. The role of the viral proteins in HIV-1 infection has been, however, less investigated. We will review contributions dedicated to the pathogenesis of HIV-1 infection focusing on studies identifying the function of the viral envelope glycoprotein (Env) in the clinical progression because of its essential role in the initial events of the virus life-cycle. Some analysis showed that inefficient viral Envs were dominant in non-progressor individuals. These poorly-functional viral proteins resulted in lower cellular activation, viral replication and minor viral loads. This limited viral antigenic production allows a better immune response and a lower immune exhaustion. Thus, the properties of HIV-1 Env are significant in the clinical outcome of the HIV-1 infection and AIDS pathogenesis.
•Large strip cropping of four crops reduced soybean aphid abundance.•A better natural control of soybean aphid was observed in strips.•Land equivalent ratio was higher in 18m strips than in control ...plots, indicating potential higher economic return.
Strip cropping could be used to deliver several eco-services, including reducing pest pressure. The objective of this study was to evaluate the impact of the management of a strip cropping system of soybean, wheat, corn and vetch on soybean aphid Aphis glycines Matsumura, its natural enemies and on the harvest of soybean. Experimental set up of 18m and 36m strips were installed in 2006 on an organic farm at Les Cèdres, Québec, Canada and compared with control plots of 180m of soybean. Each plot was replicated two times on the farm and measured 1km long. Observations of soybean aphid and natural enemies were carried out on 18 plants per replicate strips and control plots during summer 2007–2010. Abundance of soybean aphid was reduced between 33 and 55% in strips compared with the control plots during both high infestation years (2007 and 2009), while natural control (prey/predator ratio and parasitism rate) was more efficient in strips in 2009 and 2010. Land equivalent ratio (LER), an indicator of yield production was higher in 18m strips than in control plots. Strip cropping could be envisaged as an effective managing tool against soybean aphid in North America.
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