A Management Guide for Invasive Plants in Southern Forests James ...

30Tractor-Mounted Wetblade and Cut-SprayMower ApplicatorsWetblade and cut-spray mowers are similar to “bushhogs” except herbicide is applied during or immediatelyafter the cutting operation. One tractor-powered systemdispenses herbicide onto the lower blade surface thatwipes it onto the stems at the time of cutting. Control isinconsistent with this technology. Another system featuresan after-compartment behind the cutting deck that spraysherbicide onto the cut stems. The task of mowing and applyingherbicides takes place in two specialized chambers.In the first chamber (the mower deck), the brush encountersa set of 6-inch blades capable of cutting stems 2 to 3inches in diameter. The mowed debris is removed from themowing chamber through a side discharge, not allowingthe cut biomass to pass through the herbicide applicationchamber. Behind the mowing chamber is an enclosedherbicide chamber where the cut stubble encounterstwo treatment phases—a row of nozzles spray herbicidedirectly onto and through the stubble, not on the ground.Any herbicide that passes by the stubble is caught by anapplicator consisting of scrapers, brushes, and chains; theapplicator wipes herbicide onto the stubble in the secondapplication stage. These systems assure precise herbicideapplication to the mowed area and prevent spray drift.Wetblade mower systems also can deliver some biocontrolagents. Under certain conditions, this capability canintegrate biological with mechanical control of invasives.Wetblade devices also can be added to normal brush sawsfor simultaneous cutting and treating of stumps.Backpack Mist BlowersBroadcast applications can be made with a gasolinepoweredbackpack mist blower. A wind turbine creates finedroplets that penetrate into shrubby stands and onto thefoliage, but these droplets readily drift with wind and fog. Asa safeguard to nontarget plants, foliar-active herbicides areusually recommended. These applications are only suitablefor internal lands with dense infestations where driftof the mist-spray drops will be intercepted by target foliageand not move to nontarget plants or lands. Wind is criticalfor controlling this application. Wind must be minimal andmoving away from a lane or spot of application into thetarget foliage. Applications must cease when gusts beginto occur. Privets have been treated successfully with thismethod in winter using a glyphosate herbicide when thehardwood overstory was mainly without leaves.Wetblade brush mower applies herbicide while cutting.Wetblade system with two cutting heads.Backpack mist blower.Steven T. Manning Steven T. Manning