Weed and Disease Problems in Soybean Tomislav Duvnjak Agricultural Institute Osijek CROATIA Danube Soya Innovation and Research: Current status and future plans, 7th May 2015, Berlin WEEDS Outstanding competitors to cultivated plants in terms of space, water, nutrient as well as light Presented everywhere and more resistant than cultivated plants (high or low temperatures, drought, long and heavy moisture/rain, etc.) Cause losses by reducing yields through interference (competition) by lowering crop quality and by hindering harvest. Weeds can be most effectively managed in soybeans with a well-planned program: • a thorough analysis of the field situation, • use of a combination of cultural practices, • use of appropriate herbicides. The most effective weed control system depends of: • kinds of weeds in the field • soil characteristics, • tillage practices, • crop rotation, • and soybean row width. Broadleaf weeds Ambrosia artemisiifolia ANNUAL Amaranthus retroflexus PERENNIAL Amaranthus hybridus Abutilon theophrasti Capsella bursa-pastoris Chenopodium polyspermum Grass weeds Chenopodium album Sorghum halepense Grass weeds Datura stramonium Agropyron repens Echinocloa crus-galli Fallopia convolvulus Cynodon dactylon Setaria glauca Galinsoga parviflora Poa pratensis Setaria viridis Hibiscus trionum Digitaria sanguinalis Matricaria chamomilla Panicum Polygonum lapatifolium Broadleaf weeds dichotomiflorum Polygonum persicaria Cirsium arvense Panicum capillare Sinapis arvensis Cichorium intybus Solanum nigrum Convolvulus arvensis Sonchus asper Symphytum officinale Sochus oleraceus Daucus catora Stellaria media Lathyrus tuberosus Veronica agrestis Rumex obtusifolius Veronica persica Sonchus arvensis Xanthium strumarium Calystegia sepium Chemical weed treatment Agricultural management pre-sowing Crop rotation pre-emergence Inter-row cultivation post-emergence broadcast applied band applied The bottom line of any weed management decision is cost. Aplying band rather than broadcast herbicide and cultivate once, annual savings on 100 ha could be 1100 – 2650 Euro. Helps avoid development of herbicide-resistant weeds. Inexpensive way to control weeds that escape broadcast treatment. Commonly used in row crop production (combined with a band of herbicide applied over the crop row). Inter-row cultivation can be a means to reduce herbicide use. Benefit – the most attributed to weed control, also improved soil aeration and reduced soil compaction, may increase available water. Soybean injury can occur with certain herbicides, particularly when stressed from adverse environmental conditions. Certain additives can enhance injury from postemergence herbicides. Herbicides persistence in soil and potential injury to rotational crops. Ambrosia artemisiifolia Ambrosia artemisiifolia Abutilon theophrasti Xanthium strumarium Sorghum halepense Amaranthus retroflexus Convolvulus arvensis Solanum nigrum Important role in in disease epidemiology in all branches of plant production. Weeds enables pathogen survival in extreme environmental conditions and in absence of the main host for several years. As alternative hosts, connect vegetation years, host and locations – epidemiological or green bridges. “Parasite mycopopulation of weeds in row crops” “Role of weeds in epidemiology of diseases of row crops” Abutilon theophrasti: Wild host for three fungal parasites of soybean First Report of Phomopsis longicolla on Cocklebur ( Xanthium strumarium ) in Croatia Xanthium strumarium L. as the host to the fungi Sclerotinia sclerotiorum (Lib.) de Bary DESEASES Often reduces soybean yield. More than 100 pathogens are known that affect soybean, about 35 are importan economically. Fungal Bacterial Viral Nemathodes All plant parts are susceptible to a number of pathogens: seed rots and seedling diseases, foliar diseases, root and stem diseases. Reduces quality and quantity of grain yield. As number of hectares under soybean increase, increase the number and severity of soybean diseases. The economic importance of any single disease may vary from one geographic area to another in any one season. Conservative estimation of worldwide losses to all soybean diseases is about 11% of the amount produced. HOST total of characteristics favouring susceptibility Bacterial diseases Bacterial blight Pseudomonas amygdali pv. glycinea Xanthomonas axonopodis pv. glycines Bacterial pustules = Xanthomonas campestris pv. glycines Curtobacterium flaccumfaciens pv. flaccumfaciens Bacterial tan spot = Corynebacterium flaccumfaciens pv. flaccumfaciens Curtobacterium flaccumfaciens pv. flaccumfaciens Bacterial wilt Ralstonia solanacearum = Pseudomonas solanacearum Wildfire Pseudomonas syringae pv. tabaci Viral diseases Alfalfa mosaic genus Alfamovirus, Alfalfa mosaic virus (AMV) Bean pod mottle genus Comovirus, Bean pod mottle virus (BPMV) Bean yellow mosaic genus Potyvirus, Bean yellow mosaic virus (BYMV) Brazilian bud blight genus Ilarvirus, Tobacco streak virus (TSV) Cowpea chlorotic mottle genus Bromovirus, Cowpea chlorotic mottle virus (CCMV) Mung bean yellow mosaic genus Begomovirus, Mung bean yellow mosaic virus (MYMV) Peanut mottle genus Potyvirus, Peanut mottle virus (PeMoV) Peanut stripe genus Potyvirus, Peanut stripe virus (PStV) Peanut stunt genus Cucumovirus, Peanut stunt virus (PSV) Soybean chlorotic mottle genus Caulimovirus, Soybean chlorotic mottle virus (SbCMV) Soybean crinkle leaf genus Begomovirus, Soybean crinkle leaf virus (SCLV) Soybean dwarf genus Luteovirus, Soybean dwarf virus (SbDV) Soybean mosaic genus Potyvirus, Soybean mosaic virus (SMV) Soybean severe stunt genus Nepovirus, Soybean severe stunt virus (SSSV) Tobacco ringspot = bud genus Nepovirus, Tobacco ringspot virus (TRSV) blight Fusarium spp. Downy mildew (Peronospora manschurica) Sclerotinia blight White mold Sclerotinia sclerotiorum Soybean cyst nematode (SCN), Heterodera glycines DIAPORTHE/PHOMOPSIS Complex (D/P) on soybean in Europe Phomopsis longicolla (PL) Phomopsis seed decay Diaporthe phaseolorum var. caulivora (DPC) Stem canker Diaporthe phaseolorum var. sojae (DPS) Pod and stem blight Different field damage .