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In order to evaluate the long-term effect of the new fumigant DMDS and its potential to be a part of IPM of root-knot nematodes, a two-year experiment was conducted on cucumber in a greenhouse in Bulgaria. In the first year, DMDS was applied in comparison with farmer nematicide strategy and untreated control in the first cucumber crop. After two consequent catch crops—lettuce in the winter period—a second cucumber crop followed in spring–summer. In this crop, the DMDS effect was studied with no treatment and was integrated into the post-planting strategy with Trichoderma spp. and garlic extract at plots previously treated with DMDS. The effect of DMDS was followed until 450 days after fumigation. Nematocidal efficacy of DMDS was 96% and the yield increased 65.5% in the first cucumber crop, and 80% and 100% in the second cucumber crop, respectively, when nothing was done or a combined strategy with Trichoderma spp. and garlic extract was followed. The DMDS effect on 44 non-target soil nematode genera was also followed. The negative impact of the fumigation was limited in time as non-target nematode communities regained previous crop levels in five months during our study. Therefore, DMDS can be properly included in soil IPM programmes and appears very promising for the protected crop industry in Europe.

Species of the genus Hemicycliophora de Man, 1921 are not very often reported from natural or agricultural areas of Bulgaria. Hemicycliophora labiata Colbran 1920 was reported from the region of Blagoevgrad (Choleva-Abadjieva and Budurova 1983) but in later studies no other records of the genus were found. We isolated specimens of Hemicycliophora from intensively irrigated patches with wilt and postponed plants from a strawberry field in the Plovdiv region (30.10.2015) and a golf course in the Dobrich region (27.07.2019). Nematodes were isolated by Oostenbrink elutriator followed by 72 h exposition, killed by gently heating at temperature of 55oC and fixed in FAA. Fifty two specimens from Plovdiv region and 31 specimens from Dobrich were mounted in glycerol after Seinhorst (1959). The specimens from Plovdiv were identified as H. poranga Monteiro & Lordello, 1978. Ther morphology is similar to those of the population described from Pistachino, Italy (Subbotin et al. 2017). According to our knowledge this is the first record of the species on the Balkans. The population from Dobrich was similar morphologically to Polish populations of H. epicharoides Loof, 1968 (Brzeski 1998). It differed by a longer vulvar sleeve in some of the specimens and a generally less stout tail. That is first record of the species in Bulgaria, but it was found on the Balkans in Serbia and Greece (Krnjaic and Krnjaic 1976, Subbotin et al. 2017). Morphometrics and microphotograph for both species were obtained.

The Mediterranean fruit fly Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae) is considered to be one of the world’s most destructive fruit pests because of its global distribution, wide host range and rapid dispersal. In the period 1956–2006, transient populations of the pest have been reported regularly in Bulgaria. The Bulgarian Food Safety Agency (BFSA) initiated monitoring of C. capitata in 15 regions of the country. The surveys were conducted during the period 2013–2018, using Jackson traps with attractant trimedlure and Tephri traps with Biolure. The presence of adults of C. capitata was confirmed in peach, apple and mixed orchards, as well as in private yards at five locations in southern and south-eastern Bulgaria: Blagoevgrad, Kyustendil, Pazardzhik, Plovdiv and Sliven. The results from the five-year monitoring showed a variable abundance of C. capitata adults captured in different years and localities. The highest mean captures were recorded in 2014 (195) and 2018 (422), no specimen of the C. capitata was found in 2017. In 2018 the most abundant captures were from fruit gardens in Plovdiv (297♀;65♂) and Sliven (18♀; 22♂). Over the entire study period, the lowest rate of adult captures was in July and August (only a few individuals in traps in each region). The population abundance began to increase at the beginning of mid-September and a peak was observed at the beginning of mid-October. The results on the seasonal population fluctuations obtained are similar to data from neighbouring countries: northern Greece, Montenegro, Croatia, Romania, and Turkey.

In Bulgaria the plant parasitic nematode Heterodera filipjevi was firstreported in the region of Karnobat at the end of 20th century. Laboratory and field experiments on the seasonal dynamics of the species were conducted. The age structure and the population density of the nematodes were studied during the vegetation period. Delay inthe juvenile development and respectively emergency of white females was observed under both controlled and field conditions in barley for the varieties Aheloy, Veslets, and Obzor and under field conditions only in the Milena wheat variety. The laboratory tests showed that fodder barley Aheloy was resistant and Veslets and Obzor were moderately susceptible to the nematode. The Mirjana wheat variety demonstrated high susceptibility, whiletherest of the wheat and barley varieties had intermediate position.

In 2008, the spotted wing drosophila, Drosophila suzukii 1931 (Diptera: Drosophilidae) was detected for the first time in Europe (Spain). Currently the species is distributed in most Balkan countries and in 2014 it was also found in Bulgaria. The host plants of D. suzukii include cherry, strawberry, raspberry, blackberry, blueberry, peach, grape, plum, apricot and many others. In 2011 a climatic model was developed to determine the potential for permanent establishment and spread of the invasive species in Bulgaria. Specialized software (CLIMEX v. 3) was used to create maps of the ecoclimatic indices (EI). The model predicts that under the current climatic conditions D. suzukii can be established on the whole territory of the country and develop 3–7 generations per year. In 2014 and 2015 a total of 670 adult individuals were trapped. The sex ratio was 3.5 males to 1 female. The greatest numbers of D. suzukii adults were captured using Tephri-traps, followed by specialized Riga cup traps. The high male to female ratio and the low number of flies trapped in spring were likely due to the development of transient populations of the species or insufficient effectiveness of the traps. No damages by D. suzukii were observed on fruit crops. In the region of Plovdiv the number of trapped flies was significantly higher in comparison with Blagoevgrad and Kjustendil. The developed predictive model indicates up to 7 generations per yearfor the regionof Plovdiv. This prognosis was confirmed by the monitoring data: D. suzukii was established at the highest number of sites and with greatest abundance in the area.

This paper describes a decision-support scheme (DSS) for mapping the area where economically important loss is likely to occur (the endangered area). It has been designed by the PRATIQUE project to help pest risk analysts address the numerous risk mapping challenges and decide on the most suitable methods to follow. The introduction to the DSS indicates the time and expertise that is needed, the data requirements and the situations when mapping the endangered areas is most useful. The DSS itself has four stages. In stage 1, the key factors that influence the endangered area are identified, the data are assembled and, where appropriate, maps of the key factors are produced listing any significant assumptions. In stage 2, methods for combining these maps to identify the area of potential establishment and the area at highest risk from pest impacts are described, documenting any assumptions and combination rules utilised. When possible and appropriate, Stage 3 can then be followed to show whether economic loss will occur in the area at highest risk and to identify the endangered area. As required, Stage 4, described elsewhere, provides techniques for producing a dynamic picture of the invasion process using a suite of spread models. To illustrate how the DSS functions, a maize pest, Diabrotica virgifera virgifera, and a freshwater invasive alien plant, Eichhornia crassipes, have been used as examples.

International audience; Pest Risk Analyses (PRAs) are conducted worldwide to decide whether and how exotic plant pests should be regulated to prevent invasion. There is an increasing demand for science-based risk mapping in PRA. Spread plays a key role in determining the potential distribution of pests, but there is no suitable spread modelling tool available for pest risk analysts. Existing models are species specific, biologically and technically complex, and data hungry. Here we present a set of four simple and generic spread models that can be parameterised with limited data. Simulations with these models generate maps of the potential expansion of an invasive species at continental scale. The models have one to three biological parameters. They differ in whether they treat spatial processes implicitly or explicitly, and in whether they consider pest density or pest presence/absence only. The four models represent four complementary perspectives on the process of invasion and, because they have different initial conditions, they can be considered as alternative scenarios. All models take into account habitat distribution and climate. We present an application of each of the four models to the western corn rootworm, Diabrotica virgifera virgifera, using historic data on its spread in Europe. Further tests as proof of concept were conducted with a broad range of taxa (insects, nematodes, plants, and plant pathogens). Pest risk analysts, the intended model users, found the model outputs to be generally credible and useful. The estimation of parameters from data requires insights into population dynamics theory, and this requires guidance. If used appropriately, these generic spread models provide a transparent and objective tool for evaluating the potential spread of pests in PRAs. Further work is needed to validate models, build familiarity in the user community and create a database of species parameters to help realize their potential in PRA practice.