Garden Gate – October 2019

Prevent the possibility of pests

David Trinklein

Associate Professor of Horticulture,

University of Missouri

If you’ve fought the disheartening battle against pests and

disease in the garden, then you might feel an urgency to

keep them out. A professor of horticulture at the University

of Missouri, Dr. David Trinklein practices integrated pest

management, a comprehensive approach to controlling

pests that seeks to reduce the use of pesticides.

NO HOME FOR PESTS Cleaning up the

garden is key to not only removing infestations,

but preventing invasions in the first place. Even

if you think you don’t have a pest or disease

problem, Dr. Trinklein says they are probably

lurking unseen or nearby, and with the proper

conditions, they can quickly multiply out of

control. In his opinion, the garden needs to

be thoroughly cleaned up in the fall, even if your

garden is seemingly problem-free.

HOW CLEAN IS CLEAN? The main concern is that

disease inoculum, pest eggs and larvae will make debris

their home for the winter until they can emerge in full force

in spring. So rake up all fallen leaves and debris, such as

dead annuals and vegetables, and cut back all perennials

to the crown. If there is any disease infecting the leaves or

stems, like the peony diseased with powdery mildew in the

photo above, you want to remove any opportunity for it to

spread or for borer pests to overwinter in pithy perennial

stems. Compost dead material only if you are sure your

compost pile gets hot enough to kill pests and disease

(usually around 140 degrees F for multiple days). Use a

compost thermometer to help you know. If you aren’t sure,

bag up debris and dispose of it in the trash or city compost.

GOOD BUGS? His final philosophy: We might do our

pollinators a greater service by cleaning up the fall garden

and taking steps to reduce the need for pesticides, which

harms the pollinators in the end.

GardenGateMagazine.com | GARDEN GATE 31

Sarah works to make her garden a pollinator

habitat not just because of her work for the

Xerces Society, but because of the entertain-

ment value, too. Growing more native plants

and creating a habitat for wildlife means her

garden is alive with busy bees and butterflies. So how

does she create a pollinator’s haven? To sum it up: Don’t bother

cleaning up the garden at all.

LEAVE LEAVES Let your leaves be (even if they fall on the

lawn). You can rake a light layer up to use as mulch in your

beds if you’d prefer. Chopping leaves with your mower might

harm queen bees and butterfly eggs, such as the red-banded

hairstreak, whose larvae also eat the leaf litter. You might be

concerned about smothering out patches of grass in your

lawn. But it’s actually helpful to almost 70 percent of native

bees who need access to bare ground to make nests.

A motto at Xerces: Every yard should have a dead log. Many

species of bees, such as mason bees and leaf-cutter bees,

use decaying wood in their habitat, as well as lady beetles,

fireflies, butterfly pupae and many other beneficial insects.

CUT PERENNIALS? Another important shelter in the

garden: your perennials. Leave as many stems as possible over

the winter. Perennials with pithy stems, such as bee balm, aster

and goldenrod, provide nesting sites for bees. As early as you

can in spring, cut back stems at a variety of heights from 6 to

24 inches. Providing a fresh cut helps bees access the stems.

As small carpenter bees, yellow-faced bees and leaf-cutter

bees emerge from their overwintering sites, they’ll find easy

access to the cut stems, where they can make nests and raise

more bees. After cutting this once, don’t cut again for risk of

removing nests. Notice in the photo how the sedum’s new

growth is about to overtake the old stems.

Nurture beneficial pollinators

Sarah Foltz Jordan

Pollinator Conservation Specialist,

Xerces Society

It doesn’t

take most

plants long

in spring to

cover old

stems with

new growth.

Carefully cut

back stems to

the crown, the

place where the

stems emerge

from the soil,

and don’t leave

behind any

infected leaves.

GG14930_33_FallCleanUp.indd 31GG14930_33_FallCleanUp.indd 31 6/26/2019 10:28:14 AM6/26/2019 10:28:14 AM

Preventthepossibilityofpests

David Trinklein

AssociateProfessorofHorticulture,

UniversityofMissouri

If you’vefoughtthedishearteningbattleagainstpestsand
disease inthegarden,thenyoumightfeelanurgencyto
keep themout.A professorofhorticultureattheUniversity
of Missouri,Dr.DavidTrinkleinpracticesintegratedpest
management,a comprehensiveapproachtocontrolling
pests thatseekstoreducetheuseofpesticides.
NO HOMEFORPESTSCleaningupthe
garden iskeytonotonlyremovinginfestations,
but preventinginvasionsinthefirstplace.Even
if you thinkyoudon’thavea pestordisease
problem,Dr.Trinkleinsaystheyareprobably
lurking unseenornearby,andwiththeproper
conditions,theycanquicklymultiplyoutof
control. Inhisopinion,thegardenneedsto
be thoroughlycleanedupinthefall,evenif your
garden isseeminglyproblem-free.
HOWCLEANISCLEAN? Themainconcernis that
disease inoculum,pesteggsandlarvaewillmakedebris
their homeforthewinteruntiltheycanemergeinfullforce
in spring.Sorakeupallfallenleavesanddebris,suchas
dead annualsandvegetables,andcutbackallperennials
to the crown.If thereis anydiseaseinfectingtheleavesor
stems, likethepeonydiseasedwithpowderymildewinthe
photo above,youwanttoremoveanyopportunityforit to
spread orforborerpeststooverwinterinpithyperennial
stems. Compostdeadmaterialonlyif youaresureyour
compostpilegetshotenoughtokillpestsanddisease
(usually around 140 degreesF formultipledays).Usea
compostthermometertohelpyouknow.If youaren’tsure,
bag up debrisanddisposeofit inthetrashorcitycompost.
GOODBUGS? Hisfinalphilosophy:Wemightdoour
pollinatorsa greaterservicebycleaningupthefallgarden
and takingstepstoreducetheneedforpesticides,which
harms thepollinatorsintheend.

GardenGateMagazine.com | GARDEN GATE 31

Sarahworkstomakehergardena pollinator

habitatnotjustbecauseofherworkforthe

XercesSociety,butbecauseoftheentertain-

mentvalue,too.Growingmorenativeplants

andcreatinga habitatforwildlifemeansher

gardenis alivewithbusybeesandbutterflies.Sohow

doesshecreatea pollinator’shaven?Tosumit up:Don’tbother

cleaningupthegardenatall.

LEAVELEAVESLetyourleavesbe(evenif theyfallonthe

lawn).Youcanrakea lightlayeruptouseasmulchinyour

bedsif you’dprefer.Choppingleaveswithyourmowermight

harmqueenbeesandbutterflyeggs,suchasthered-banded

hairstreak,whoselarvaealsoeattheleaflitter.Youmightbe

concernedaboutsmotheringoutpatchesofgrassinyour

lawn.Butit’sactuallyhelpfultoalmost 70 percentofnative

beeswhoneedaccesstobaregroundtomakenests.

A mottoatXerces:Everyyardshouldhavea deadlog.Many

speciesofbees,suchasmasonbeesandleaf-cutterbees,

usedecayingwoodintheirhabitat,aswellasladybeetles,

fireflies,butterflypupaeandmanyotherbeneficialinsects.

CUTPERENNIALS? Anotherimportantshelterinthe

garden:yourperennials.Leaveasmanystemsaspossibleover

thewinter.Perennialswithpithystems,suchasbeebalm,aster

andgoldenrod,providenestingsitesforbees.Asearlyasyou

caninspring,cutbackstemsata varietyofheightsfrom6 to

24 inches.Providinga freshcuthelpsbeesaccessthestems.

Assmallcarpenterbees,yellow-facedbeesandleaf-cutter

beesemergefromtheiroverwinteringsites,they’llfindeasy

accesstothecutstems,wheretheycanmakenestsandraise

morebees.Aftercuttingthisonce,don’tcutagainforriskof

removingnests.Noticeinthephotohowthesedum’snew

growthis abouttoovertaketheoldstems.

Nurture beneficial pollinators

Sarah Foltz Jordan

Pollinator Conservation Specialist,

Xerces Society

It doesn’t

take most

plants long

in spring to

cover old

stems with

new growth.

Carefully cut

back stems to

the crown, the

place where the

stems emerge

from the soil,

and don’t leave

behind any

infected leaves.