Biology of field dodder (Cuscuta campestris Yunk.) and options for its control

Radi sagledavanja kompletne biologije, ekologije i mogućnosti suzbijanja Cuscuta campestris Yunk. urađena je determinacija 23 populacije vilinih kosica primenom svetlosne i skening elektronske mikroskopije, a potom i molekularnim metodama (PCR). Takođe, ispitivan je uticaj različitih temperaturnih režima i rizobakterija (PGPR) na klijanje semena C. campestris, kao i uticaj različitih svetlosnih tretmana (crvene, daleko crvene i plave svetlosti) na klijanje, rast i visinu vezivanja klijanaca viline kosice za stablo lucerke. Proučavan je uticaj C. campestris na morfološke (vizuelna ocena i sveža masa), anatomske (anatomska građa lista i stabla lucerke; lista i lisne drške šećerne repe) i fiziološke parametre (relativni sadržaj hlorofila, ukupni karotenoidi, azot, fosfor, kalijum, organska i mineralna materija i fluorescencija hlorofila) kod biljaka lucerke i šećerne repe u uslovima sa i bez primene herbicida (imazetapira, glifosata, propizamida). Efikasnost imazetapira, glifosata, propizamida i dikvata za suzbijanje viline kosice u lucerištu je ispitivana u poljskim uslovima. Determinacijom 23 populacije vilinih kosica ustanovljene su dve vrste roda Cuscuta i to: Cuscuta campestris Yunk. i Cuscuta epithymum (L.) Nath.. Ustanovljeno je da je optimalna temperatura za klijanje semena C. campestris 30˚C, dok je pri tretmanu sa crvenom svetlošću (1h u toku dana) procenat klijanja semena bio najveći, a u tretmanu sa daleko crvenom svetlošću (45 min u toku dana) je zabeležen najveći procenat vezanih klijanaca za stablo lucerke na visini od 4,65 cm. Takođe, najveći procenat klijanja viline kosice je zabeležen pri tretemanu sa rizobakterijom Azotobacter chroococcum izolovanom iz rizosfere pšenice. Na osnovu analize dobijenih rezultata utvrđeno je da su za većinu merenih parametara (vizuelna ocena i sveža masa; relativni sadržaj hlorofila i ukupnih karotenoida, efektivni prinos i intezitet fluorescencije, varijabilna fluorescencija, odnos varijabilne i maksimalne fluorescencije; debljina epidermisa stabla, debljina primarne kore, debljina centralnog cilindra i prečnik stabla lucerke; debljina epidermisa lica i naličja lista, debljina palisadnog i sunđerastog tkiva, debljina mezofila lista lucerke i šećerne repe; prečnik traheja, hidraulična provodljivost lisne drške, površina ksilema, prečnik ćelija floema i površina floema lisne drške šećerne repe) najveće vrednosti bile kod nezaraženih biljaka lucerke i šećerne repe, zatim kod zaraženih a tretiranih herbicidima i najmanje kod zaraženih sa C. campestris a ne tretiranih biljaka. C. campestris je uticala na smanjenje gotovo svih merenih parametara anatomske građe stabla, listova i lisne drške biljaka domaćina, što nije bio slučaj kod pojedinih fizioloških parametara...Determination of 23 populations of field dodder was conducted using light and scanning electron microscopy and subsequent molecular (PCR) methods in order to fully examine the biology and ecology of Cuscuta campestris and options for its control. The effects of different temperatures and rhizobacteria (PGPR) on germination of C. campestris seeds, as well as effects of different light treatments (red, far-red and blue light) on germination, growth, and height of attachment points of field dodder shoots on alfalfa stems were also investigated. We examined the effects of C. campestris on morphological (visualisation and fresh weight), anatomical (anatomy of leaf and stem of alfalfa; leaf and petiole of sugar beet) and physiological parameters (relative chlorophyll content, total carotenoids, nitrogen, phosphorus, potassium, organic and mineral matter and chlorophyll fluorescence) in alfalfa and sugar beet plants exposed and unexposed to herbicides (imazethapyr, glyphosate, propyzamide). The efficacy of imazethapyr, glyphosate, propyzamide and diquat in controlling field dodder in alfalfa crop was examined in field trials. After examining 23 populations of field dodder, two species of the genus Cuscuta were identified: Cuscuta campestris Yunk. and Cuscuta epithymum (L.) Nath. An optimal temperature for germination of C. campestris seeds was found to be 30˚C and treatment with red light (for 1h at daytime) produced the highest percentage of germinated seeds, while the highest percentage of seedlings attached to alfalfa stems at 4.65 cm height was found after treatment with far-red light (for 45 min at daytime). Also, the highest percentage of germinated field dodder seeds was recorded after treatment with the rhizobacterium Azotobacter chroococcum isolated from wheat rhizosphere. An analysis of our data showed that the highest values of most parameters (visualization and fresh weight; relative content of chlorophyll and total carotenoids, effective yield and intensity of fluorescence, variable fluorescence, variable/maximal fluorescence ratio; thickness of stem epidermis, thickness of cortex, thickness of central cylinder and stem diameter of alfalfa; thickness of upper and lower leaf epidermis, thickness of palisade and spongy mesophylls, thickness of mesophyll in alfalfa and sugar beet leaves; diameter of tracheids, petiole hydraulic conductance, xylem area, diameter of phloem cells and petiole phloem area of sugar beet) were found in non-infested alfalfa and sugar beet plants, then in infested plants treated with herbicides, and the lowest in plants infested by C. campestris but untreated with herbicides. C. campestris was found to affect and reduce nearly all parameters of stem, leaf and petiole anatomy of the host plants, in contrast to some physiological parameters..