Modern techniques in colorado potato beetle (Leptinotarsa decemlineata say) control and resistance management: History review and future perspectives

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Colorado potato beetle, CPB (Leptinotarsa decemlineata Say), is one of the most important pests of the potato globally. Larvae and adults can cause complete defoliation of potato plant leaves and can lead to a large yield loss. The insect has been successfully suppressed by insecticides; however, over time, has developed resistance to insecticides from various chemical groups, and its once successful control has diminished. The number of available active chemical control substances is decreasing with the process of testing, and registering new products on the market are time-consuming and expensive, with the possibility of resistance ever present. All of these concerns have led to the search for new methods to control CPB and efficient tools to assist with the detection of resistant variants and monitoring of resistant populations. Current strategies that may aid in slowing resistance include gene silencing by RNA interference (RNAi). RNAi, besides providing an efficient tool for gene functional studies, represents a safe, efficient, and eco-friendly strategy for CPB control. Genetically modified (GM) crops that produce the toxins of Bacillus thuringiensis (Bt) have many advantages over agro-technical, mechanical, biological, and chemical measures. However, pest resistance that may occur and public acceptance of GM modified food crops are the main problems associated with Bt crops. Recent developments in the speed, cost, and accuracy of next generation sequencing are revolutionizing the discovery of single nucleotide polymorphisms (SNPs) and field of population genomics. There is a need for effective resistance monitoring programs that are capable of the early detection of resistance and successful implementation of integrated resistance management (IRM). The main focus of this review is on new technologies for CPB control (RNAi) and tools (SNPs) for detection of resistant CPB populations

CA21134 - Towards zer0 Pesticide AGRIculture : European Network for sustainability (T0P-AGRI-Network)

Current crop protection in EU agriculture is heavily reliant on chemical pesticides to suppress weeds, pests and pathogens. In view of the serious health and environmental consequences, European public authorities, consumers, and society at large are demanding drastically reduced use of chemical pesticides, in the context of a production of safe, high-quality and affordable food. Furthermore, farmers are calling for research and innovation solutions to protect crops with non-chemical means while maintaining a viable farm economy. A change of direction and paradigm is needed to foster this transition, emphasizing preventive crop protection based on agroecological practices that to prevent pest outbreaks and infestations. The proposed Cost Action T0P-AGRI-Network targets the transition “Towards zer0 Pesticide AGRIculture”, aiming at preparing the future of an agriculture free of synthetic pesticides and of nature-derived pesticides that negatively impact environment and human health. T0P-AGRI-Network tackles this challenge by create and organize a wide research community with the aim to form a European leading network with high and transdisciplinary expertise around the common objective of pesticide-free agriculture, with a particular focus on young scientists. To enable a redesign of the food system as a whole, T0P-AGRI-Network will promote a concerted mobilization of scientists, farmers, processing industries, public authorities and consumers by associating them closely with the activities that will be carried out in the Cost Action

Changes in corn rootworm wing morphology are related to resistance development

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is the most serious pest of maize across the US Corn Belt and now Europe. The beetle has repeatedly demonstrated its ability to adapt to pest management strategies through evolution of resistance to conventional insecticides, the cultural practice of crop rotation and now to the Bacillus thuringiensis (Bt) toxin which is produced by genetically modified maize. In this study, the wing morphology of 358 western corn rootworm adults from Iowa, Indiana and Illinois, USA, was investigated using geometric morphometric procedures. The populations investigated comprised resistant (i.e. soybean-maize rotation and Bt-maize variants) and non-resistant beetle populations. Data analysis was divided into two groups: (1) resistant versus non-resistant and (2) rotation-resistant versus Bt-maize rootworm populations. Results showed that morphological differences exist in the hind-wing shape of both rotation and Bt-maize-resistant versus non-resistant populations and rotation-resistant versus Bt-maize-resistant variants. Across all three types of rootworm variants investigated, the movement of landmarks 8, 9 and 14 drove the wing shape differences found. These landmarks relate to the basal radial vein and are a key anatomical character used to distinguish different wing morphotypes in rootworm. This study demonstrates the utility of hind-wing morphology/shape as an inexpensive and accessible population biomarker for rootworm. With simple equipment (camera mounted microscopes or flatbed scanners) and readily available free software to capture and analyse landmark (shape and size) data, it is possible to effectively monitor pest resistance development and associated field-based population-level differences. The biological implications of the differences in wing shape found and how this relates to rootworm flight and consequently its dispersal and invasion capabilities are also explored

Sredstva za zaštitu bilja na poljoprivrednim površinama – rezidue u gujavicama i procjena potencijalno toksičnih učinaka na okoliš

The environmental risk assessment of plant protection products for soil organisms is mainly based on the results of laboratory and extended laboratory studies while the link from the laboratory to realistic field conditions over several seasons is not well established. The current environmental risk assessment is applied to a single active ingredient and does not consider that soil organisms are exposed to varying degrees to a mixture of active ingredients from different pesticides. In this study, earthworm samples were collected from eight fields in Croatia during two growing seasons and analyzed for 300 active ingredients. The concentrations of 26 analyzed active ingredients ranged between 0.000 and 0.247 mg/kg earthworm fresh weight with a mean of 0.005 mg/kg earthworm fresh weight. The percentage of samples with values below the limit of detection (LOD = ½ LOQ), values below the limit of quantification (LOQ = 0.001 mg/kg) and values above LOQ were 33, 44 and 23 %, respectively. Based on publicly available draft assessment reports from European Commission and European Food Safety Authority, degradation parameters (DT50, DT90) were used to calculate degradation curves and the current concentration in soil at the date of earthworm sampling. Subsequently, compoundspecific bioconcentration factors in soil were determined by dividing the analyzed pesticide residues in earthworms by the calculated concentrations in soil. The results of the study showed that most active ingredients do not pose a risk to earthworms and have no secondary poisoning potential to birds and mammals that feed on them. The retrospective analysis method of analytically measured neonicotinoid residues in earthworm samples can be reliably used to calculate degradation and concentration curves in soil at the time of sampling.Procjena ekološkog rizika sredstava za zaštitu bilja za organizme u tlu uglavnom se temelji na rezultatima laboratorijskih i proširenih laboratorijskih studija dok veza između laboratorija i realnih poljskih uvjeta tijekom nekoliko sezona nije dobro utvrđena. Trenutna procjena rizika za okoliš primjenjuje se na pojedinačne aktivne tvari i ne uzima u obzir da su organizmi u tlu izloženi mješavini mješavini aktivnih tvari različitih pesticida. U istraživanju su prikupljeni uzorci gujavica s osam polja u Hrvatskoj tijekom dvije vegetacijske sezone. Analizirani su na 300 aktivnih tvari. Koncentracije 26 analiziranih aktivnih tvari kretale su se od 0,000 do 0,247 mg/kg svježe mase gujavica sa srednjom vrijednosti od 0,005 mg/kg svježe mase gujavica. Postotak uzoraka s vrijednostima ispod granice detekcije (LOD = ½ LOQ), vrijednosti ispod granice kvantifikacije (LOQ = 0,001 mg/kg) i vrijednosti iznad LOQ iznosio je 33, 44 and 23%. Na temelju javno dostupnih nacrta izvješća o procjeni Europske komisije i Europske agencije za sigurnost hrane, parametri degradacije (DT50, DT90) korišteni su za izračunavanje krivulja razgradnje i koncentracije u tlu u vrijeme uzorkovanja gujavica. Potom su određeni faktori biokoncentracije specifičnih za spoj u tlu dijeljenjem analiziranih ostataka pesticida u gujavicama s izračunatim koncentracijama u tlu. Rezultati istraživanja pokazali su da većina aktivnih tvari ne predstavlja rizik za gujavice i nema sekundarni potencijal trovanja za ptice i sisavce koji se njima hrane. Metoda retrospektivne analize analitički izmjerenih rezidua neonikotinoida u uzorcima gujavica može se pouzdano koristiti za izračunavanje krivulja razgradnje i koncentracije u tlu u vrijeme uzorkovanja

European corn borer and its parasites overwintering abundance and damages on different corn FAO maturity groups

European corn borer (ECB) is one of the most significant maize pests in the world and also in Croatia. ECB causes yield reduction from 2 to 25%, even more in years favorable for its development. According to estimations, these losses are around 7%. About 90% of the hybrids had some resistance to whorl-leaf feeding (first-generation ECB) and 75% had some resistance to sheath and sheath-collar feeding (second-generation ECB). Along with resistance, modern maize hybrids possess certain level of tolerance. The main aim of this paper was to determine moth eclosion of the overwintering generation and presence of the parasites of ECB larvae during the overwintering as well as to estimate population density of ECB on maize growing area in Croatia. Also, we aimed to establish the differences among different maize FAO maturity groups in damage caused by ECB larvae. Estimated overwintering population was over 8,000 moths/ha i.e. more than 4 million larvae of first generation. During the overwintering four different parasites attacked the larvae. Two species belong to the order Hymenoptera (Cotesia marginiventris Cresson and Eriborus terebrans Gravenhorst) and two species belong to the order Diptera (Ramonda spathulata Fallén and Lydella thompsoni Herting). One caterpillar predator species Paragymnomerus spiricornis Spinola (Hymenopetra) overwinters in maize stalks as well. The highest attack of the first ECB generation was recorded on FAO maturity group 500. The damage from second ECB generation was the highest on FAO groups 400 and 500. The maize of the higher FAO groups has high and robust stems with large number of big leaves. That intensive vegetative growth is a biological characteristic that attracts first generation of ECB to intensifying egg lying. High population level of the first generation also leads to high level of second ECB generation which ultimately caused yield reduced on the hybrids of longer vegetation period (medium-late FAO maturity groups)

Neonicotinoid Residues in Earthworms and Ground Beetles under Intensive Sugar Beet Production: Preliminary Study in Croatia

Neonicotinoids are pesticides widely used for pest control in agriculture with undesirable effects on pollinators. However, other beneficial insects are exposed to insecticides that are not lethal to them but may accumulate and affect their vital characteristics. The objective of this study was to determine neonicotinoid residues in two types of beneficial soil organisms. The first group includes ground beetles (family: Carabidae, order: Coleoptera). They are important in the food web within existing ecosystems, especially in agricultural areas. The second group includes earthworms (family: Lumbricidae, order: Opisthopora) as humifiers, important members of the soil fauna. Fauna was collected at two sugar beet growing areas in Croatia under intensive sugar beet management. Ground beetles were collected from six plots of sugar beet fields treated with imidacloprid and thiamethoxam or left untreated with neonicotinoids. Earthworms were collected from the eight fields involved in four-year sugar beet crop rotation (sugar beet, maize, soybean, oilseed rape). Detection of neonicotinoid residues was performed by LC-MS/MS, SPE-QuEChERS method. The limit of quantification (LOQ) was 0.001 mg/kg. In ground beetles, the highest concentration of imidacloprid was detected at 0.027 mg/kg, while the residues of thiamethoxam and clothianidin were below LOQ. The highest concentration of imidacloprid in earthworms was 0.2141 mg/kg, while residues of thiamethoxam did not exceed 0.0008 mg/kg. This is the first study of this kind on Croatian territory and provides a valuable first insight into the ecotoxicological status of beneficial soil fauna. More comprehensive studies are needed to assess the extent of accumulation in and to take further steps regarding conservation programs for beneficial soil organisms

Pest management challenges and control practices in codling moth: A review

2020 by the authors. Licensee MDPI, Basel, Switzerland. The codling moth, Cydia pomonella L., is a serious insect pest in pome fruit production worldwide with a preference for apple. The pest is known for having developed resistance to several chemical groups of insecticides, making its control difficult. The control and management of the codling moth is often hindered by a lack of understanding about its biology and ecology, including aspects of its population genetics. This review summarizes the information about the origin and biology of the codling moth, describes the mechanisms of resistance in this pest, and provides an overview of current research of resistant pest populations and genetic research both in Europe and globally. The main focus of this review is on non-pesticide control measures and anti-resistance strategies which help to reduce the number of chemical pesticides used and their residues on food and the local environment. Regular monitoring for insecticide resistance is essential for proactive management to mitigate potential insecticide resistance. Here we describe techniques for the detection of resistant variants and possibilities for monitoring resistance populations. Also, we present our present work on developing new methods to maintain effective control using appropriate integrated resistance management (IRM) strategies for this economically important perennial pest

Neonicotinoid Residues in Earthworms and Ground Beetles under Intensive Sugar Beet Production: Preliminary Study in Croatia

Neonicotinoids are pesticides widely used for pest control in agriculture with undesirable effects on pollinators. However, other beneficial insects are exposed to insecticides that are not lethal to them but may accumulate and affect their vital characteristics. The objective of this study was to determine neonicotinoid residues in two types of beneficial soil organisms. The first group includes ground beetles (family: Carabidae, order: Coleoptera). They are important in the food web within existing ecosystems, especially in agricultural areas. The second group includes earthworms (family: Lumbricidae, order: Opisthopora) as humifiers, important members of the soil fauna. Fauna was collected at two sugar beet growing areas in Croatia under intensive sugar beet management. Ground beetles were collected from six plots of sugar beet fields treated with imidacloprid and thiamethoxam or left untreated with neonicotinoids. Earthworms were collected from the eight fields involved in four-year sugar beet crop rotation (sugar beet, maize, soybean, oilseed rape). Detection of neonicotinoid residues was performed by LC-MS/MS, SPE-QuEChERS method. The limit of quantification (LOQ) was 0.001 mg/kg. In ground beetles, the highest concentration of imidacloprid was detected at 0.027 mg/kg, while the residues of thiamethoxam and clothianidin were below LOQ. The highest concentration of imidacloprid in earthworms was 0.2141 mg/kg, while residues of thiamethoxam did not exceed 0.0008 mg/kg. This is the first study of this kind on Croatian territory and provides a valuable first insight into the ecotoxicological status of beneficial soil fauna. More comprehensive studies are needed to assess the extent of accumulation in and to take further steps regarding conservation programs for beneficial soil organisms

Two decades of invasive Western corn rootworm population monitoring in Croatia

Western corn rootworm (WCR) is the worst pest of maize in the United States, and since its spread through Europe, WCR is now recognized as the most serious pest affecting maize production. After the beetle\u27s first detection in Serbia in 1992, neighboring countries such as Croatia have established a national monitoring program. For more than two decades WCR adult population abundance and variability was monitored. With traditional density monitoring, more recent genetic monitoring, and the newest morphometric monitoring of WCR populations, Croatia possesses a great deal of knowledge about the beetle\u27s invasion process over time and space. Croatia\u27s position in Europe is unique as no other European nation has demonstrated such a detailed and complete understanding of an invasive insect. The combined use of traditional monitoring (attractant cards), which can be effectively used to predict population abundance, and modern monitoring procedures, such as population genetics and geometric morphometrics, has been effectively used to estimate inter-and intra-population variation. The combined application of traditional and modern monitoring techniques will enable more efficient control and management of WCR across Europe. This review summarizes the research on WCR in Croatia from when it was first detected in 1992 until 2018. An outline of future research needs is provided

Wing shape changes: a morphological view of the Diabrotica virgifera virgifera European invasion

An analysis of the hind wing morphology (size and shape) within and among western corn rootworm, Diabrotica virgifera virgifera LeConte, populations over a large geographic scale in Europe was conducted. The changes in hind wing shape and size detected were related to identifiable invasion processes (i.e. multiple introduction events into Europe), first characterised using genetic markers. Overall implications from this work suggest that geometric morphometric techniques can be used to detect population changes related to invasions and could therefore serve as a cheaper and more accessible alternative \u27biomarker\u27 to more expensive and specialised-use genetic markers, such as microsatellites or SNPs, when investigating biological invasions