Vig­i­lance urged as re­gion spared worst of corn mould

The Glengarry News - - The Glengarry News - BY RICHARD MA­HONEY News Staff

Eastern On­tario has been spared the worst of a corn mould in­fes­ta­tion that has had a “cat­a­strophic” im­pact on some pro­duc­ers in the prov­ince.

But spe­cial­ists stress the need for vig­i­lance as a vom­i­toxin, de­oxyni­valenol, or DON, has spoiled large vol­umes of corn.

Tests con­ducted dur­ing the corn ear mould and my­co­toxin sur­vey found one el­e­vated sam­ple in the eastern re­gion of the prov­ince. Mould con­tent lev­els were ranked from A to C, with a C sam­ple de­not­ing a level of 2 parts per mil­lion or more. Only one crop in Eastern On­tario had a C rank­ing, ac­cord­ing to the tests of 146 corn ear sam­ples that were col­lected across the prov­ince from Sep­tem­ber 21 to 28.

All of the other ap­prox­i­mately 25 sam­ples in Eastern On­tario iden­ti­fied A and B lev­els, read­ings that were un­der 2 ppm.

Over­all, vis­ual mould symp­toms were more ap­par­ent this year and vom­i­toxin anal­y­sis re­vealed a greater in­ci­dence of sam­ples with el­e­vated DON con­cen­tra­tions, ac­cord­ing to the sur­vey car­ried out by the On­tario Min­istry of Agri­cul­ture, Food and Ru­ral Af­fairs, Grain Farm­ers of On­tario and the On­tario AgriBusi­ness As­so­ci­a­tion.

“While 60 per cent of sam­ples tested be­low 2 ppm, it is im­por­tant to re­mem­ber that grow­ers should re­main vig­i­lant and be aware of man­age­ment op­tions in those fields with higher ear mould and DON con­cen­tra­tions,” reads the re­port co-au­thored by crop spe­cial­ists Ben Rosser and Al­bert Tenuta.

Corn ear moulds such as Gib­berella and their cor­re­spond­ing my­co­tox­ins oc­cur ev­ery year in On­tario. These my­co­tox­ins, par­tic­u­larly vom­i­toxin (DON) pro­duced pri­mar­ily by Gib­berella/Fusar­ium ear moulds can be dis­rup­tive when fed to live­stock, es­pe­cially hogs.

“As we have seen in pre­vi­ous years when en­vi­ron­men­tal con­di­tions were favourable for dis­ease de­vel­op­ment, the On­tario grain in­dus­try has been pre­pared and able to process corn with min­i­mal im­pact,” the spe­cial­ists say.

At the same time, they cau­tion, “This sur­vey does not fully cap­ture all re­gions of the prov­ince, and re­sults can vary lo­cally from field to field depend­ing on hy­brid, plant­ing date, in­sect feed­ing, ro­ta­tion, residue lev­els, fungi­cide prac­tices and mois­ture. These re­sults may not fully cap­ture what is oc­cur­ring in your fields, and there­fore mon­i­tor­ing is rec­om­mended.”

Timely har­vest is im­por­tant. Leav­ing dis­eased grain in the field al­lows the ear rot fungi to keep grow­ing, which will in­crease the risk of mouldy grain and my­co­toxin con­tam­i­na­tion since most ear rot fungi con­tinue to grow (and po­ten­tially pro­duce my­co­tox­ins) un­til the grain has less than 15 per cent mois­ture. In se­verely in­fected fields, grow­ers should con­sider har­vest­ing grain at higher mois­ture and then dry it to less than 15 per cent to min­i­mize fur­ther my­co­toxin ac­cu­mu­la­tion.

Col­lect sam­ples

If a field con­tains a sig­nif­i­cant level of ear mould, pro­duc­ers are ad­vised to col­lect a rep­re­sen­ta­tive sam­ple prior to har­vest and have it tested for my­co­tox­ins be­fore stor­ing the grain or feed­ing it to live­stock.

A lab test is of­ten the only re­li­able way to defini­tively de­ter­mine my­co­toxin pres­ence and lev­els.

DON in­fects corn, wheat and bar­ley. If in­gested, an­i­mal feed made from DON-in­fected grain can cause ma­jor health is­sues for live­stock, while farm­ers can also suf­fer se­ri­ous med­i­cal prob­lems if the mould is in­haled.

Ethanol pro­duc­ers and dis­til­leries can’t sell byprod­ucts from the in­fected corn.

GFO Pres­i­dent Markus Haerle, a pro­ducer from St-Isi­dore, re­cently ob­served: “Al­though we have yet to see all the end re­sults, we know that the cur­rent DON sit­u­a­tion is cat­a­strophic for some of our farm­ers.” Pre­vent­ing ear rots and mould can be dif­fi­cult since weather con­di­tions are crit­i­cal to dis­ease de­vel­op­ment.

Look­ing ahead to 2019, pro­duc­ers are re­minded that hy­brid se­lec­tion is im­por­tant but while some tol­er­ant hy­brids are avail­able, none has com­plete re­sis­tance.

Grow­ers are en­cour­aged to dis­cuss with their lo­cal seed sup­plier what ear mould tol­er­ant hy­brids are best suited for their op­er­a­tion. Crop ro­ta­tion can re­duce the in­ci­dence of ear rots, while sev­eral fo- liar fungi­cides aimed at sup­press­ing ear rots have also been reg­is­tered. Cul­tural prac­tices such as tillage have been shown to have lim­ited suc­cess in pre­vent­ing ear and ker­nel rots.

SIGNS OF TROU­BLE: Ears show the var­i­ous species of mould that can af­fect corn.

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