Con­sid­er­a­tions when ap­ply­ing a pre-har­vest man­age­ment her­bi­cide

Prairie Post (East Edition) - - FALL AUCTION GUIDE - Al­berta Agri­cul­ture

Ap­pli­ca­tion of a pre-har­vest man­age­ment her­bi­cide to a stand­ing crop - closely fol­low prod­uct la­bel guide­lines.

“While pre-har­vest man­age­ment her­bi­cides do not speed-up crop ma­tu­rity, they help max­i­mize crop yield and qual­ity po­ten­tial,” ex­plains Neil What­ley, crop spe­cial­ist at the Al­berta Ag-Info Cen­tre.

“Ap­pli­ca­tion of th­ese prod­ucts can also as­sist with con­trol­ling peren­nial weeds and weed escapes from the grow­ing sea­son.”

Th­ese prod­ucts are cat­e­go­rized as ei­ther a des­ic­cant or a pre-har­vest weed con­trol her­bi­cide. Des­ic­cants are rec­og­nized as har­vest aid prod­ucts. Des­ic­cants are com­monly con­tact her­bi­cides, and their mode of ac­tion is gen­er­ally fast act­ing.

He says that ap­pli­ca­tion of th­ese prod­ucts has­ten dry-down of a crop that is al­ready ma­ture as well as dry­ing the veg­e­ta­tive growth of weeds, en­sur­ing ear­lier and eas­ier di­rect com­bin­ing of a stand­ing crop.

“Glyphosate, on the other hand, has a slower, sys­temic mode of ac­tion that al­lows it to translo­cate through a plant. There­fore, glyphosate is the pre­ferred pre-har­vest her­bi­cide ap­plied to con­trol peren­nial weeds like quack­grass and Canada this­tle.”

Des­ic­cants and glyphosate are reg­is­tered to be ap­plied when the crop’s seed is at phys­i­o­log­i­cal ma­tu­rity. Prod­uct la­bels ex­plain the cor­rect crop stage for ap­pli­ca­tion as well as spec­i­fy­ing the ap­pro­pri­ate wa­ter vol­ume used with a spe­cific her­bi­cide.

“Ap­pli­ca­tion ear­lier than at proper seed ma­tu­rity can neg­a­tively im­pact yield,” says What­ley. “Ex­ceed­ing the prod­uct la­bel rate or ap­ply­ing th­ese prod­ucts ear­lier than at the rec­om­mended crop stage can ex­ceed a prod­uct’s max­i­mum residue limit (MRL).”

“An MRL, es­tab­lished through re­search dur­ing the her­bi­cide’s reg­is­tra­tion process, is the le­gal amount of her­bi­cide residue al­lowed in har­vested grain. Heath Canada as­sures that MRLs are based on residue amounts that are sig­nif­i­cantly be­low a level that would neg­a­tively im­pact hu­man health.”

Crop Pro­tec­tion 2019 con­tains prod­uct la­bel guide­lines, and the web­site Keep it Clean fea­tures a use­ful drop down menu for var­i­ous crops and pre-har­vest man­age­ment her­bi­cides.

What­ley adds that Canada is a ma­jor grain ex­porter, and im­port­ing coun­tries can set their own grain im­port MRL level, which may not be the same as Canada’s level.

“Other end-users, es­pe­cially those pur­chas­ing bar­ley for the malt mar­ket, or oat millers, have their own MRL reg­u­la­tions or do not al­low pre-har­vest her­bi­cides to be used at all. When un­cer­tain, grow­ers are en­cour­aged to con­sult their grain buyer prior to pre-har­vest her­bi­cide ap­pli­ca­tion.”

Newspapers in English

Newspapers from Canada

© PressReader. All rights reserved.