21
THECOMMERCIAL GREENHOUSEGROWER • MAY 2018
CRO0 0ROTECTION •
When it comes toprotected edibles, biological control has
been awell established technique formany years, but for
ornamentals growers there canbe challenges in terms of
acceptable thresholds for damage and sometimes there
is a cropprotection challengewhich requires chemical
intervention. RichardCrowhurst reports.
Control programmes for protected environments aremore
advanced than any other sector in theUK, because full
control over the crop environment is possible,” points out
SelchukKurtev, IPMManager for CertisUK. “Successful
pest anddisease control comes from taking a holistic
view, considering how all the elements interact andwork
with eachother. For example, whenusing a fungicide,
considering the effect thismay have onmacro-biologicals
andpollinators is important to factor in.Whenplant
protection applications are scheduled, pollinator hives
shouldbe shut to ensure any risk to thepollinators
isminimised.”
“Any chemical sprays usedor planned tobe usedby
the grower need tobe reported togrower’s bio-control
advisor who can then assess the compatibility of the
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stressesDr CarolineReid, UKCommercial Manager at
BiolineAgroSciences. “Your BASIS registered advisor will
then inform the grower of the harm this couldpotentially
do to the insects. Ideally the grower will discuss the
potential use of a chemical control before it is applied
and then the risk canbe assessed. At thebeginningof
the season, pre-treatments canbe usedon the same
basis, i.e.: informing thebio-control advisor. There are
compatability charts availablewhichdetail the hazards of
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aJJess [Oese [OeTsel]es iM [Oe` aYe JVUfideU[ eUV\NO ¹
Shepoints out that somepests such as theSouthern
green stinkbug (Nezara viridula), leafhoppers, and high
levels of aphidpestsmay all still require chemical control.
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red spidermite, aphids, caterpillars,Mealybugs and
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controls or biopesticides for their control, but the last two
relymore on chemical or physical control methods.”
“In recent seasons glasshouse growers have reported
new issueswithDiamondBackMoth caterpillar damage,”
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IeeU^idesWYead iU field JYVWs i[»s VUl` YeJeU[l` [Oa[ i[
had causeddamage inside. Inperspective, it wasn’t nearly
so serious apest as some of themorewidely recognised
caterpillars, such as theCarnationTortrix (Cacoecimorpha
pronubana), but therewere certainly some serious cases
VM disfiN\YiUNVM MVliaNe
“It has highlighted howquickly newpests can invade
- andhowgrowers need tobe ready to react. Diamond
BackMoth can still be effectively controlledby broad-
spectrum insecticides, but in an IPM system, which is
now thepredominantly favoured approach,most growers
would favour alternatives topyrethroids- or neonicotinoid-
based treatments.
“Last year thrips, once again, proved tobe themajor
challenge to control inprotected vegetables and,
especially, ornamentals. There are some good Integrated
PestManagement programmes available, primarily based
aroundAmblyseius cucumeris; however, growers have
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early infestations – so if the thrips aremore established,
thebiological will have tobe used in conjunctionwith
an insecticide,most likely abamectinor spinosad.
Alternatively introductions of thepredatory bugOrius
laevigatus, whichwill attack all stages of thrips, could
be considered. The launchof newTafari (pymetrozine)
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insecticide for aphids inprotected crops, which is safe to
CARENEEDED TOCOMBINE BIOLOGICAL
ANDCHEMICAL CROP PROTECTION
DiamondBackMoth.
