Effects of the low-level western corn rootworm egg infestation on maize plants in the field

From the economic perspective, the western corn rootworm (WCR), Diabrotica virgifera sp. virgifera (Col., Chrysomelidae), poses the gravest threat to the field maize production in Serbia. The purpose of this study is to examine the impact of WCR larvae on the morphology of maize characters during a low-level artificial egg infestation. A field experiment involving the Serbian cultivar 'NS-640' was carried ou Serbia, in 2016. In the experimental field, a total of 96 maize plants were selected, marked and arranged in 48 pairs. Each pair consisted of an infested plant (WCR eggs injected in the root zone) and an uninfested plant (distillate water injected in the root zone). The number of leaves, height and stem diameter of the plants observed were recorded. Root damage and root weight were measured and evaluated at the end of the trail. For the purpose of statistical analysis, the non-parametric Kruskal-Wallis one-way analysis of variance and a correlation matrix were used. The statistical analysis performed indicate a highly significant difference in the number of leaves and plant height between the infested and uninfested maize plants examined in July (the third field observation). During the last field inspection, significant differences were recorded only between the stem diameters of the infested and uninfested maize plants. A negative correlation was found to exist between the root damage and root weight of the plant pairs. There were positive correlations between the stem diameter, plant height and number of leaves of the infested plants, whereas positive correlations were found between the root damage and plant height of the uninfested plants

MONITORING OF FLIGHT PHENOLOGY OF RASPBERRY CANE MIDGE RESSELIELLA THEOBALDI BARNES (DIPTERA: CECIDOMYIIDAE) BY PHEROMONE TRAPS IN WESTERN SERBIA

The flight phenology of the raspberry cane midge Resseliella (Thomasiniana) theobaldi Barnes (Diptera, Cecidomyiidae) was monitored over three successive years (2006-2008) in a raspberry orchard of the Fruit Research Institute Čačak, at the 'Zdravljak' site. This was the first time that large white delta traps baited with the raspberry cane midge sex pheromone were used. No insecticides were used during the monitoring period. Throughout the period, over three growing seasons, the midge presence was detected from April-May to September-October. During the three years, there were variations in the numbers of midges caught per trap, as well as those in the total numbers of midges trapped across years and peak numbers per trap. The highest total number (2,419) of midges during the season and the highest number of midges per trap in a sample (729) were recorded in 2007. The earliest maximum catch per trap (729) occurred on 11 May, 2007

Experimental research of the tube absorbers of kinetic energy during collision

Razvoj elemenata za apsorbciju energije sudara je sastavni deo pasivne zaštite putničkih vagona. Pasivna zaštita ima zadatak da posledice sudara svede na minimum. Apsorber prikazan u radu napravljen je od standardne bešavne cevi u kvalitetu P235T1 i konusnog prstena kvaliteta C45E. Predstavljeno rešenje se zasniva na korišćenju specijalnih elemenata koji apsorbuju određenu količinu kinetičke energije sudara putem kontrolisane plastične deformacije, čime se značajno smanjuje deo energije koji se prenosi na noseću strukturu vozila. Pri sudaru dolazi do sabijanja-provlačenja cevi kroz konusni prsten. Težište rada je na eksperimentalnim istraživanjima radi određivanja stvarnih karakteristika apsorbera ovog tipa. Na osnovu analize dobijenih rezultata ispitivanja, predloženo je konačno konstruktivno rešenje apsorbera, kao elementa buduće konstrukcije čeonog dela postolja vagona.Development of collision energy absorbing elements is a constituent part of passive protection of passenger coaches. The target of passive protection is to minimize the collision consequences. The absorber, described in this paper, is constructed from a standard seamless tube of the quality P235T1 and conical ring of the quality C45E. The solution presented is based on the application of special elements that absorb a certain amount of collision kinetic energy by means of controlled plastic deformation, significantly decreasing the part of the energy which is transferred to the vehicle bearing structure. The tube is compressed - pushed through the conical ring in collision. The paper focuses on the quasi-static and dynamics experimental research. Based on the analysis of the results obtained in the research, a final design of the absorber is suggested as a part of the future front part of vehicle bearing structure

Mogućnost monitoring leta D.v. virgifera obradom slike sa feromonske klopke pomoću Raspberry Pi uređaja

Necessity for seasonal monitoring of economically most important pests in different crops, increase input costs of their surveillance. In maize fields, Western corn rootworm - WCR (Diabrotica virgifera sp. virgifera) is economically the most important species and presents a limiting factor for production of maize in continuous cultivation. Its occurrence is usually monitored with pheromone traps. However, as previously mentioned they are time and money consuming due to constant need for field inspections. Since in research projects, finances predefined for weekly inspection of traps are most often non-eligible, there is a need for developing a novel approach for pest monitoring. The use of IT technologies along with commercially available pheromone traps could provide precise information about the situation in traps without frequent field inspections. Also, they are easy to maintain, manipulate and require minimum costs. This work aimed to assess the potential use and the precision of a sensor device with camera, in monitoring the WCR flight on pheromone traps. Sensor device equipped with small camera can capture images of a pheromone trap sticky base and transfer them to a remote server for review, storage and analysis. The main idea in this paper is to present a system that uses a method based on analysis of the image variations of the pheromone pest traps, performed on devices placed in their vicinity which means that sending every image to the server is avoided. In this way, information about the variations in pheromone traps can be found in one location without unnecessarily sending the same images to the server. The obtained results indicate that the proposed method for monitoring the variations of the number of caught specimens on sticky surfaces of pheromone traps, based on the variations of the dark surface on the images, can be a reliable tool in further work.Neophodnost sezonskog monitoringa ekonomski najznačajnih štetočina u različitim usevima uzrokuje rast ulaznih troškova u poslovima nadzora njihove pojave. U usevu kukuruza, kukuruzna zlatica (Diabrotica virgifera sp. virgifera) je ekonomski najznačajnija štetočina i predstavlja ograničavajući faktor proizvodnje u monokulturi. Brojnost i pojava ove vrste se najčešće prati feromonskim klopkama. Međutim, kao što je napomenuto, njihova primena iziskuje dosta vremena i novca, usled konstantne potrebe za poljskim osmatranjima i obilascima klopki. U istraživačkim projektima sredstva predviđena za nedeljne preglede klopki su veoma često neprihvatljiv deo budžeta, što nameće potebu za razvojem novog pristupa monitoringu štetočina. Upotreba IT tehnologija uporedo sa komercijalno dostupnim feromonskim klopkama omogućava precizne informacije o stanju na klopkama, uz manje terenskih izlazaka, jednostavnost i niske troškove održavanja i manipulacije. Cilja rada je bio procena mogućnosti upotrebe i preciznosti senzorskih uređaja sa kamerom u monitoringu leta kukuruzne zlatice na fero-klopkama. Pomoću senzorskih uređaja opremljenih malim kamerama mogu se snimiti slike na mestu feromonskih klopki i proslediti do udaljenog servera za pregled, skladištenje i analizu. Ideja u ovom radu je prikaz sistema koji koristi metodu promene zauzetosti površine prilikom analize slike koja se izvršava na uređaju posredniku postavljenog pre servera. Na taj način se informacije o promeni brojnosti insekata u klopci mogu saznati na jednom lokalitetu bez nepotrebnog slanja istovetnih slika na server. Dobijeni rezultati ukazuju da se predloženi metod praćenja promene brojnosti na bazi promene površine prisustva tamnih polja (uhvaćenih insekata na lepljivoj površini feromonske klopke) može koristiti kao pouzdan alat u daljem radu

Experimental research of the tube absorbers of kinetic energy during collision

Razvoj elemenata za apsorbciju energije sudara je sastavni deo pasivne zaštite putničkih vagona. Pasivna zaštita ima zadatak da posledice sudara svede na minimum. Apsorber prikazan u radu napravljen je od standardne bešavne cevi u kvalitetu P235T1 i konusnog prstena kvaliteta C45E. Predstavljeno rešenje se zasniva na korišćenju specijalnih elemenata koji apsorbuju određenu količinu kinetičke energije sudara putem kontrolisane plastične deformacije, čime se značajno smanjuje deo energije koji se prenosi na noseću strukturu vozila. Pri sudaru dolazi do sabijanja-provlačenja cevi kroz konusni prsten. Težište rada je na eksperimentalnim istraživanjima radi određivanja stvarnih karakteristika apsorbera ovog tipa. Na osnovu analize dobijenih rezultata ispitivanja, predloženo je konačno konstruktivno rešenje apsorbera, kao elementa buduće konstrukcije čeonog dela postolja vagona.Development of collision energy absorbing elements is a constituent part of passive protection of passenger coaches. The target of passive protection is to minimize the collision consequences. The absorber, described in this paper, is constructed from a standard seamless tube of the quality P235T1 and conical ring of the quality C45E. The solution presented is based on the application of special elements that absorb a certain amount of collision kinetic energy by means of controlled plastic deformation, significantly decreasing the part of the energy which is transferred to the vehicle bearing structure. The tube is compressed - pushed through the conical ring in collision. The paper focuses on the quasi-static and dynamics experimental research. Based on the analysis of the results obtained in the research, a final design of the absorber is suggested as a part of the future front part of vehicle bearing structure

Susceptibility of dried berries to infestation by Plodia interpunctella (Lepidoptera: Pyralidae) in correlation with total sugar content: Poster

By assessing the degree of resistance of stored products to infestation by insect pests and correlating it with physical, chemical and nutritional characteristics of products, we could gain a real insight in these pests feeding preferences, and consequently in their biology and ecology. The aim of this study was to assess the degree of resistance of five dried berry species (strawberry, raspberry, blackberry, black chokeberry and cranberry) to infestation caused by the major pest of dried berries, Plodia interpunctella. Susceptibility was rated based on the Index of susceptibility (IS) for insect development and the Susceptibility rating. Dried cranberries were absolutely resistant to infestation by P. interpunctella (IS = 0) - no larvae reached the adult stage. Four other dried berry species were also resistant (IS ranged 2.01 – 2.44). In other words, dried cranberries are very unsuitable food for P. interpunctella, while other four tested species were slightly more suitable. The content of total sugars in dried berries varied from 24.2% (black chokeberry) to 72.8% (strawberry), but important correlation between IS and total sugar content was not found. By analysing feeding preferences of P. interpunctella, we can undertake different pest-management strategies for protection of stored dried fruits.By assessing the degree of resistance of stored products to infestation by insect pests and correlating it with physical, chemical and nutritional characteristics of products, we could gain a real insight in these pests feeding preferences, and consequently in their biology and ecology. The aim of this study was to assess the degree of resistance of five dried berry species (strawberry, raspberry, blackberry, black chokeberry and cranberry) to infestation caused by the major pest of dried berries, Plodia interpunctella. Susceptibility was rated based on the Index of susceptibility (IS) for insect development and the Susceptibility rating. Dried cranberries were absolutely resistant to infestation by P. interpunctella (IS = 0) - no larvae reached the adult stage. Four other dried berry species were also resistant (IS ranged 2.01 – 2.44). In other words, dried cranberries are very unsuitable food for P. interpunctella, while other four tested species were slightly more suitable. The content of total sugars in dried berries varied from 24.2% (black chokeberry) to 72.8% (strawberry), but important correlation between IS and total sugar content was not found. By analysing feeding preferences of P. interpunctella, we can undertake different pest-management strategies for protection of stored dried fruits

Pogodnost tri različite vrste leguminoza za razviće i rast populacije Acanthoscelides obtectus

Legumes are a rich source of valuable nutrients thus represent important component in human and animal nutrition. The most important and often a limiting factor in legume production is the presence of seed pests, such as the bean weevil Acanthoscelides obtectus (Say, 1831). This work tested the suitability of three different legume species (common bean, faba bean and grass pea), the species with a growing interest in the human diet, for the development of the bean weevil, aiming to provide a reliable forecast of its population growth. After four months, been weevils consumed the highest percentage of the common bean kernels (70.79%), followed by the grass pea (53.13%), and faba bean (0.42%). The progeny production and population growth were significantly affected by the tested legume species. After each month, the total number of adults was the highest on the common bean, indicating its best suitability for the weevil’s development. Based on the number of the emerged specimens after each month of the observation, the bean weevil development was unhampered and continuous also on the grass pea. The lowest number of emerged adults, in all observation periods, was in faba bean, indicating its low preference and suitability for the weevil’s development. The population growth of the bean weevil was the highest on the common bean, followed by grass pea, and it fitted best to the quadratic equation model that enabled the prediction of the population growth of the bean weevil for each legume species in the next generations.Leguminoze su višestruko značajne, jer predstavljaju dragocen izvor različitih nutrijenata u ljudskoj i životinjskoj ishrani. Njihovim uzgojem doprinosi se raznolikosti agroekosistema i pozicioniraju se kao klimatski prilagodljiv usev. Najvažniji ograničavajući faktor u proizvodnji leguminoza predstavljaju štetotočine zrna (semena), poput pasuljevog žiška Acanthoscelides obtectus (Say, 1831). U ovom radu ispitana je pogodnost tri različite leguminoze (pasulj, sastrica i bob) sa rastućom popularnošću u ljudskoj ishrani, za razviće i rast populacije pasuljevog žiška. S ciljem utvrđivanja pouzdanog modela za prognozu populacijskog rasta štetočine, rezultati su korišćeni u matematičkom modelovanju. Istraživanja pokazuju da je, posle četiri meseca, zrno pasulja konzumirano u najvišem procentu (70,79%), manje sastrice (53,13%) i najmanje zrna boba (0,42%). Na produkciju potomstva i rast populacije statistički značajno je uticala vrsta leguminoze u ishrani. Ukupan broj eklodiralih imaga, na kraju svakog meseca u eksperimentalnom periodu, bio je najveći na pasulju, što pokazuje pogodnost ove biljke hraniteljke za razviće insekta. Eklozija imaga ukazuje da je razviće moguće i na sastrici. Najmanji broj imaga je eklodirao na zrnima boba, što ukazuje na nisku preferentnost i nepogodnost za razviće ovog insekta. Rast populacije žiška najintenzivniji je na pasulju, pa na sastrici, što je u potpunosti podržano kvadratnim regresionim modelom, koji omogućava prognozu rasta populacije pasuljevog žiška u svakoj narednoj generaciji

Combining abilities for spike traits in a diallel cross of barley

Five two-row winter barley (Hordeum vulgare L.) cultivars divergent in spike traits were crossed in all possible combinations excluding reciprocals to produce 10 F1 and F2 hybrids for analysis of combining abilities. The analysis of variance of combining abilities showed significant differences for GCA and SCA in F1 hybrids and F2 generation, suggesting additive and non-additive gene action. The GCA/SCA ratio in F1 and F2 indicated the prevalence of the additive component of genetic variance for spike length, grain weight per spike and spike harvest index. By contrast, the SCA variance for grain weight per spike was higher than the GCA variance, indicating the dominance of non-additive gene action. Good GCAs were found in parents having high values for spike length (Djerdap, NS-293), grain number per spike (Vada, Jagodinac), grain weight per spike (Vada, NS-293) and spike harvest index (Djerdap, Jagodinac). None of the parents had good GCA for all traits, suggesting a potential increase in combining abilities for spike traits. The best SCA were obtained mostly from crosses between parents having high x low, high x high or average x low GCA values. Parents having high GCA values may be used to produce improved lines in hybridisation programmes. Combinations with high SCA values may yield good segregating lines in further selection programmes

Efficacy of Echium spp. water extracts as post-harvest grain protectants against Plodia interpunctella

Water extracts of three plant species of the genus Echium (E. italicum L., E. vulgare L. and E. rubrum Jacq.) were tested under laboratory conditions for their activity as potential post-harvest grain protectants against Plodia interpunctella (Hubner, 1813) (Lepidoptera: Pyralidae) larvae. Antioxidative activity and total phenolic, flavonoid and tannin contents in plant extracts were determined. The larvicidal assays were conducted with the local population of P. interpunctella from Central Serbia on kernels of Takovoanka winter wheat cultivar. The experiment was set as factorial 3x3x3x3 block design type. Three groups of larvae of different maturity were used. The larvae were exposed to three different concentrations of water extracts (1%, 2% and 5%) of three listed plant species. Mortality was registered daily during 96 hours and the efficacy was calculated using Schneider-Orelli's formula. The largest number of dead larvae was recorded in the treatment of 1% extract of E. italicum on youngest group, after 72 and 96 h. Extracts of E. vulgare and E. rubrum did not show high larvicidal effect

Prvi nalaz vodenog oraška (Trapa natans L., Trapaceae, Myrtales) u Centralnoj Srbiji

Water chestnut (Trapa natans L.) is a floating macrophyte that generates differing views on its role and importance in aquatic ecosystems. It is protected as a rare species in a number of European countries and is an invasive species in some regions of the world. T. natans inhabits stagnant and slow flowing waters that exhibit large fluctuations in water level. Occurrence records are frequently reported from the north of the Republic of Serbia (Vojvodina Province), while there are no relevant data about its habitats in southern parts of the country. The first record of T. natans in Central Serbia was from the Međuvršje Reservoir on the Zapadna Morava River (the Danube River Basin) in 2011. A marked increase in species abundance in certain sections of the reservoir was observed in 2012. High water temperatures and continuous inflow of nutrients reported in recent years will most likely induce further propagation of this species, potentially leading to further eutrophication of the system and upsetting the ecological balance of the new habitat.Vodeni orašak (Trapa natans L.) predstavlja flotantnu makrofitu koju karakteriše različita procena uloge i značaja u akvatičnim ekosistemima. Zaštićena kao prirodna retkost u većem broju evropskih zemalja, ima status invazivne vrste u pojedinim regionima sveta. T. natans je vrsta kojoj pogoduju stajaće i sporotekuće vode sa velikim variranjima vodostaja. Česti su nalazi u severnom delu Republike Srbije (Vojvodina), dok nema relevantnih podataka o staništima u južnijim delovima. Tokom 2011. godine registrovan je prvi nalaz T. natans na području Centralne Srbije u akumulaciji Međuvršje na reci Zapadnoj Moravi (Dunavski sliv). Izrazito omasovljenje vrste u pojedinim sektorima akumulacije je evidentirano u 2012. godini. Visoke temperature vode i stalan dotok nutrijenta koje se registruju zadnjih godina verovatno će usloviti dalju propagaciju vrste. To može doprineti daljoj eutrofikaciji ekosistema i narušiti postojeće ekološke ravnoteže u novom staništu