Phase out chem­i­cals in your yard

How-to guide for re­duc­ing harm to en­vi­ron­ment

Winnipeg Free Press - Section F - - HOMES - By Sara Wil­liams & Hugh Skin­ner

CON­SIDER the is­sue of chem­i­cal pes­ti­cides. Most Prairie gar­den­ers are aware of their neg­a­tive im­pact on our en­vi­ron­ment.

The ma­jor­ity of in­sec­ti­cides are broad-based rather than spe­cific. They tar­get the “good guys” as well as the pests, up­set­ting the nat­u­ral bal­ance of pest, preda­tor and par­a­sites that would nor­mally ex­ist in our land­scapes. Many are toxic to pets and peo­ple. They can en­ter our food web and our ground wa­ter.

As well, in­sects and dis­eases have a re­mark­able ca­pac­ity for adap­ta­tion and of­ten de­velop re­sis­tance to these prod­ucts, ren­der­ing them in­ef­fec­tive.

As gar­den­ers, we want to cre­ate a pleas­ing out­door en­vi­ron­ment. We may also feel pres­sure from our neigh­bours or by the per­sua­sive and per­va­sive mar­ket­ing of the man­u­fac­tur­ers of these prod­ucts to have an im­mac­u­late lawn and gar­den. But our gar­dens are not our liv­ing rooms. We should ac­cept some bumps on leaves. Our ob­jec­tives in man­ag­ing pests in our gar­dens should be to gain a sat­is­fac­tory level of con­trol with the least harm to the en­vi­ron­ment and the least risk to our fam­i­lies, neigh­bours and pets.

So how does one achieve the goal of beauty in our land­scape with­out re­sort­ing to broad-spec­trum chem­i­cal pes­ti­cides that can also have neg­a­tive im­pacts on our health and en­vi­ron­ment? Be­gin by sim­ply re­solv­ing to re­duce their use for this sea­son, and as it works, take the con­cept fur­ther. Here are some strate­gies:

Keep plants healthy. Like peo­ple, healthy plants are less vul­ner­a­ble to disease. Pro­vide op­ti­mal spac­ing. Give them the wa­ter and ex­po­sure (sun/ shade) un­der which they’ll thrive. En­sure ad­e­quate fer­til­ity, but do not over-fer­til­ize, es­pe­cially with ni­tro­gen that causes lush suc­cu­lent growth vul­ner­a­ble to in­sect and disease at­tack.

Wa­ter early in the day so fo­liage dries quickly. Where pos­si­ble, use drip ir­ri­ga­tion or soaker hoses to avoid wet­ting the fo­liage.

Use an or­ganic mulch to con­serve mois­ture, mod­er­ate soil tem­per­a­tures, con­trol the ger­mi­na­tion of weed seedlings, and pre­vent the splash of soil­borne disease or­gan­isms onto plants.

Use re­sis­tant va­ri­eties. Choos­ing in­sect and disease re­sis­tant or tol­er­ant va­ri­eties is such an easy way to avoid prob­lems. Plant breed­ers have worked long and dili­gently to se­lect these plants, so let’s take ad­van­tage of their work and use them. ‘Thun­der­child’ and ‘Dolgo’ crabap­ples are re­sis­tant to fire­b­light. ‘Drop­more’ lin­den is re­sis­tant to the leaf gall mite that causes the lit­tle bumps on lin­den and bass­wood leaves. ‘Dis­cov­ery’ elm is re­sis­tant to Dutch elm disease.

Toma­toes with re­sis­tance to late blight in­clude ‘De­fi­ant’, ‘Red Grape’ and ‘Duchess.’ Potato va­ri­eties less sus­cep­ti­ble to late blight in­clude ‘Red Pon­tiac’, ‘Red Nor­land’, ‘Ken­nebec’ and ‘Nor­land.’ The Rus­sian hol­ly­hock (Al­cea ru­gosa) is re­sis­tant to hol­ly­hock rust, while the fan columbine (Aqui­le­gia fla­bel­lata) is re­sis­tant to the columbine leaf miner.

Use traps and bar­ri­ers. Yel­low sticky traps at­tract white­flies, aphids and fun­gus gnats while blue sticky traps at­tract thrips. Tree bands painted with Tan­gle­foot can be used to cap­ture wing­less fe­male canker­worms as they climb up trees to lay their eggs. Red traps shaped like ap­ples are used to at­tract ap­ple mag­got flies.

Fab­ric row cov­ers ex­clude in­sects that eat our fruit or veg­eta­bles or lay their eggs on them such as cab­bage but­ter­flies on cab­bages, cau­li­flower and broc­coli. Home­made or com­mer­cial plant col­lars can by placed around young tomato, pep­per or cab­bage trans­plants to pre­vent cut­worm dam­age. Cir­cu­lar or square mats pre­vent the adult onion mag­got flies from lay­ing their eggs at the base of mem­bers of the onion fam­ily.

Less toxic al­ter­na­tives in­clude in­sec­ti­ci­dal soaps, di­atoma­ceous earth, and hor­ti­cul­tural oils. Bi­o­log­i­cal con­trols range from the lady bee­tles that your grand­mother was fa­mil­iar with to par­a­sitic wasps that lay their eggs within the bod­ies of harm­ful in­sects. Avoid­ing broad-spec­trum in­sec­ti­cides al­lows these ben­e­fi­cial in­sects to qui­etly go about their busi­ness, do­ing their job, largely un­sung and un­seen. Among the newer bi­o­log­i­cal con­trols are Bacil­lus thuringien­sis, a bac­te­ria used to con­trol cater­pil­lars and mos­quito lar­vae and Bacil­lus sub­til­lis, a bac­te­ria that pre­vents the de­vel­op­ment of grey mould, fire­b­light and other dis­eases.

Weeds com­pete with our gar­den plants for space, sun­light, nu­tri­ents and wa­ter. They also har­bour in­sects and dis­eases. Some have al­lelo­pathic char­ac­ter­is­tics: they pro­duce growth reg­u­la­tors that in­hibit the ger­mi­na­tion and growth of the very plants you are try­ing to nour­ish. While there is no magic one-step/no-ef­fort for­mula for con­trol­ling weeds with­out chem­i­cals, your grand­mother had it right in one sense. A hoe will do the job while sav­ing you the cost of a sum­mer mem­ber­ship in the lo­cal gym. Many less toxic al­ter­na­tives have been reg­is­tered in the last decade. Corn gluten meal doesn’t con­trol es­tab­lished weeds in your lawn but pre­vents the ger­mi­na­tion of dan­de­lions, lamb’s quar­ters, purslane and other weeds. Fi­esta is a chelated iron prod­uct that con­trols es­tab­lished broadleaf weeds. Hor­ti­cul­tural vine­gar is ef­fec­tive against weeds in their seedling stage. Sar­ri­tor is a strain of scle­ro­tinia disease that is spe­cific to dan­de­lions.

Re­mem­ber to fol­low la­bel di­rec­tions and safety pre­cau­tions on all of these prod­ucts.


Bra­conid wasp: These par­a­sitic wasps lay their eggs within the lar­vae of harm­ful



Above: Row cov­ers pre­vent cab­bage but­ter­fly moths from lay­ing their eggs on your cab­bages, broc­coli and cau­li­flower. Be­low: ‘Blue Fan’ columbine is

re­sis­tant to the columbine leaf miner.


Corn gluten meal pre­vents the ger­mi­na­tion of broadleaf weeds in your lawn.

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