Abstract/Contents: | "The University of Kentucky Weed Science program provides a weed identification service available to clientele through the local county extension offices spread across the state. This clinic assists landowners, producers, consultants and other clientele with proper identification of weedy plants and recommended control strategies. Approximately 400 to 500 samples per season are submitted to the UK Weed Science Herbarium for identification. Samples are either mailed to the clinic or submitted as an electronic submission through direct emails and the UK digital consulting system. A digitized database was assembled that represents over 9800 plant samples examined over the past 25 years. This database can be used to search for the most common weeds associated with various habitats which includes the primary grain crops (i.e. corn, grain sorghum, soybean, wheat), forage crops (i.e. alfalfa, hayfields, and pastures), turf, and other environments. This database can also be used to look at trends of developing weed problems over time, as well as to map the presence of invasive plants at the county level across Kentucky. In Kentucky corn fields the ten most frequently identified plants over the past 25 years included broadleaf signalgrass (Urochloa platyphylla), various brome grasses (Bromus spp.), beaked panicum (Panicum anceps), common mugwort (Artemisia vulgaris), purpletop (Tridens flavus), Canada thistle (Crisium arvense), trumpetcreeper (Campsis radicans), cinnamon vine (Discorea batatas), bermudagrass (Cynodon dactylon), and fall panicum (Panicum dichotomiflorum). Other troublesome weeds included honeyvine milkweed (Ampelamus albidus), burcucumber (Sicyos angulatus), bigroot morningglory (Ipomoea pandurata), and Japanese knotweed (Polygonum cuspidatum). The ten most common soybean weeds were the brome grasses, prickly sida (Sida spinosa), barnyardgrass (Echinochloa crus-galli), sicklepod (Senna obtusifolia), eastern black nightshade (Solanum ptychanthum), broadleaf signalgrass, hophornbeam copperleaf (Acalypha ostryifolia), horseweed (Conyza canadensis), smooth pigweed (Amaranthus hybridus), and eclipta (Eclipta prostrate). The top five wheat weeds included the brome grasses (eg. smooth brome, field brome, and cheat), little barley (Hordeum pusillum), field pennycress (Thlaspi arvense), Italian ryegrass (Lolium multiflorum), and annual bluegrass (Poa annua). Forage crop weeds identified in grass pastures included lanceleaf ragweed (Ambrosia bidentata), annual marshelder (Iva annua), perilla mint (Perilla frutescens), brome grasses, tickclover (Desmodium spp.), buttercup (Ranunculus spp.), sericea lespedeza (Lespedeza cuneata), nodding spurge (Chamaesyce nutans), purpletop, and beaked panicum. In hayfields, additional weeds identified included sweet vernalgrass (Anthoxanthum odoratum), hemp dogbane (Apocynum cannabinum), common velvetgrass (Holcus lanatus), little barley, barnyardgrass, and yellow foxtail (Setaria pumila). Whereas, in alfalfa the most common weeds were hairy bittercress (Cardamine hirsute), Philadelphia fleabane (Erigeron philadelphicus), common chickweed (Stellaria media), virginia copperleaf (Acalypha virginica), Italian ryegrass, and barnyardgrass. In turfgrass environments the ten most common weeds were bermudagrass, nimblewill (Muhlenbergia shreberi), ground ivy (Glechoma hederacea), Virginia buttonweed (Diodia virginiana), common lespedeza (Lespedeza striata), dallisgrass (Paspalum spp.), yellow nutsedge (Cyperus esculentus), annual bluegrass, common chickweed, and tall fescue (Schedonorus arundinaceus). Other weed species included creeping bentgrass (Agrostis stolonifera), large crabgrass (Digitaria sanguinalis), orchardgrass (Dactylis glomerata), star-of-bethlehem (Ornithogalum umbellatum), Italian ryegrass, hairy bittercress, and smooth crabgrass (Digitaria ischaemum)." |