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provide suppression through the growing season. <br /> Flea beetles feed on the leaves of leafy spurge in the summer,but most plant damage occurs after the insects have laid eggs and the <br /> resulting larvae are underground feeding on the roots.Mowing,grazing,and herbicide application are only compatible with insect <br /> bio-control if these management efforts occur in the late summer or fall after the insects have laid their eggs and newly hatched <br /> larvae are underground. <br /> Mowing and grazing are effective tools for depleting root reserves.Hand pulling or digging can reduce seed production and stress <br /> plants,but this perennial will readily grow back.For more on leafy spurge see the article"Leafy Spurge-A Perennial Problem." <br /> Top <br /> Houndstongue (Cynoglossum officinale) <br /> Houndstongue is a tap-rooted biennial that reproduces by seed only.Houndstongue <br /> germinates in summer/fall,over-winters as a rosette,bolts and flowers in <br /> spring/summer,sets seed in the fall.Plants grow to 4 feet tall with reddish-purple <br /> flowers.The velcro-like seeds are a nuisance,attaching tightly to clothing and animals. <br /> . ? Houndstongue contains alkaloid compounds that are toxic to livestock. <br /> t t r The most effective <br /> herbicides for controlling <br /> houndstongue are dicamba, " <br /> Escort,Telar,2,4-D,Plateau, <br /> SI_ and Tordon. <br /> 3' No insect biocontrol agents <br /> �i are currently available in <br /> Mkt " Colorado. g = <br /> f Digging or hand pulling <br /> >' houndstongue is effective if > a ,,; <br /> _ before seed set.Flowering y <br /> ''-�" plants should be bagged and <br /> disposed.Be sure to remove <br /> the top 2-3 inches of tap-root to prevent re-growth.For more <br /> information about houndstongue see the article"Houndstongue." <br /> 1 Top <br /> Common teasel (Dipsacus fullonum) <br /> Common teasel is a tap-rooted biennial that reproduces only by seed.Plants typically <br /> ,�. germinate in late summer or early fall,over-winter as a rosette,bolt and flower in the <br /> spring or early summer.Common teasel thrives on moist sites and can dominate <br /> wetlands.Though not yet common in Larimer County,common teasel is a significant <br /> ' weed problem on riparian areas of Boulder and Jefferson Counties. <br /> Numerous herbicides are available that effectively control teasel: Milestone,Curtail, <br /> Redeem,2,4-D,dicamba,Escort,Telar,Plateau,Tordon,and Transline.Check label <br /> restrictions for applications near water. <br /> Common tcaset ilo«crs No insect biocontrol agents are currently available for control of common teasel. <br /> Mowing can reduce seed production but plants generally re-flower and set seed from <br /> a reduced height.Hand pulling or digging is very effective prior to seed set. <br /> A Top <br />