F
Sof t
f
rui t Day
F
T
he
frui
TG
rower
• JAN
u
A
r
Y2017
although light is the primary factor, there are two egg-laying
peaks in themorning and evening coincidingwith temperature
peaks.
i
n aKent cherry orchard in 2016 themajority of eggs
were deposited at temperatures between 25C and 29C.
N
i
AB
e
M
r
lead entomologist DrMichelle
f
ountain’s talk
asked the question: “Canwe
i
PMS
w
D?Adding to the
understanding of the lifecycle of the pest leads tobetter
practical tips for improved control. So farMichelle considers
thatmass trapping has not been found tobe effective.
Complete exclusion of the flieswith finemesh netting is very
successful, but although pollinatingbumblebees can be
introduced, the nets prevent natural enemies from colonizing
the crop, which creates problems for all but blueberry crops.
i
n
the future, the development of ‘dead-end’ egg-laying sites and
hosts for the females, particularly comingout of thewinter, has
potential.
w
ork on findingparasitoids - particularly identifying
endemic species - is ongoing.
Apart frompraying for long coldwinters, how can growers
help combat S
w
Dwith husbandry?
f
irstly growers should
assess the risk for each field of soft fruit.
i
f it is surroundedby
arable cropping it is atmuch less risk than fields bordering
woodland or orchards. S
w
D is often observedbeing attracted
topuddles, so it is important to reduce humidity and avoid
over-irrigating. Mulching the groundwithwoven fabric helps as
larvae dropping to the floor are desiccated. Managing crop
canopies to reduce humidity is also important.
The trainingof all staff on the farm is vital, as all efforts to
combat the pest will contribute to the finances of the farm.
r
egular picking (every twodays, if possible) is goodpractice,
and taking fruit directly to the cold storewill arrest the
development of the larvae. Taking all thewaste fruit away from
the crop is vital and, after anaerobic treatment, it shouldbe
incorporated and not left on the surfacewhere it acts as a food
source for overwintering flies that are larger andmore able to
survive thewinter. Michelle admits that the industry is still
heavily dependent on insecticides, but current researchwill
make themmore targeted.
Michelle’s stark summarywas that S
w
D is established and
numbers continue tobuild, andwe have not reached the full
carrying capacity of the pest in the
u
K, and in future other
regions could see the pattern seen in the south-east over the
last four years. The pest can adapt todifferent temperature
regimes. Growers should adopt a focused, year-round
approach to the suppression of S
w
D that targets all the life
stages and annual phases of the pest whilst being sensitive to
natural enemies controlling other pests.
New researchondiseases
Changes in theways that strawberries are grown has led to
powderymildew taking over frombotrytis as the lead
strawberry disease, soplant pathologist Dr AngelaBerrie has
been looking for alternative treatments to control it within the
SC
e
PT
re
project. Many of the varieties grown today are very
susceptible tomildewbut the current control approach based
on fungicides is unsustainable, due to the loss of actives and
reduced effectiveness of older products. So far four new
fungicide products giving excellentmildew control have been
identified and one (LunaSensation) will be available next
season, and another – Talius - is expected to receive an
e
AM
u
in time. The results frommore trialswork on combining seven
or 14-day fungicide programmeswith biostimulants, on trial
cropswithmuch disease present, have yet tobe evaluated.
Angela considers that further workwill include commercial
triallingof promising combinations, and the use of a
management system tomake themost of what is available.
The risk of mildew, based on a forecasting system from
u
niversity of
h
ertfordshire, cropmonitoring and the growth of
the plant will affect the choice of disease control product
whether protectant, eradicant or biocontrol agent. This
approachwill be particularly important formildew control in
long season ever-bearers.
e
rika
w
edgwood of ADAS reported results on themost
feareddisease for raspberries – raspberry root rot. Container
growing and standing containers on plastic can prevent
10
All currentandpromisingnewvarieties
strawberryplants, raspberryplantsandasparagusplants
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