Wheat quality can be defined in terms of inherent quality attributes those under genetic control and seasonal quality attributes. One of the parameters of wheat quality is insect-damage.

1. Digital Re-print -
September | October 2012
Insect-damaged wheat: suni bug, cereal bug, sunn
pest, wheat bug, shield bug, shell bug
Grain & Feed Milling Technology is published six times a year by Perendale Publishers Ltd of the United Kingdom.
All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies,
the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of
information published.
©Copyright 2010 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form
or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1466-3872
www.gfmt.co.uk

2. FEATURE
Insect-damaged wheat:
suni bug, cereal bug, sunn pest, wheat bug, shield bug, shell bug
by Prof. Dr. M. Hikmet Boyacioglu, Group R&D Director-Cereal Foods Institute
Director, Doruk Group Holding, Turkey
This article was derived from the presentation made in 4th International Mühlenchemie Symposium, September 8-9, 2011.
W
heat quality can be defined In New Zealand, Nysius huttoni is thought to time of ripening of wheat, or a combination
in terms of inherent quality be the cause of the problem (Lorenz and of these factors.
attributes those under genetic Meredith, 1988). According to Paulian and Popov (1980)
control and seasonal quality attributes This article reviews the economical some 10-15 million hectares (25-37 million
(Table 1, 2). One of the parameters importance and varietal susceptibility of acres) of cereal cultivation are at risk, and
of wheat quality is insect-damage. insect damage, methods for the prediction in certain years chemical treatments may be
of damage, effects on baking quality, suni bug applied to seven million hectares (about 17
It is widely accepted that insect-damaged management and improvement of bread million acres) in an attempt to limit the dam-
wheat contains a bug salivary proteinase, quality. age, especially if the crop is wheat.
which causes rapid relaxation of dough A report prepared and published in 1993
and, consequently, results in the production Economical importance by FAO/ICARDA authorities, states that
of loaves with poor volume and texture The economical importance of the cereal about 1.3 million acres field is inflicted by E.
(Cressey, 1987, Every et al., 1996). Damage bug E. integriceps on the wheat plant con- integriceps, and a part of 582.000 acres are
to wheat and its baking quality, due to pre- centrates on two main points of negative
harvest insect attack, has been reported effects. First of all, the bite of only one
across the world including Germany, Spain, mature insect, which survives under the Table 1: Inherent Quality Attributes
Hungary, Italy, Turkey, Iran, Iraq, and New winter conditions, is more than enough to Protein type and quality (extensibility, stability
Zealand amongst others. kill the plant body. Yield losses attributable to mixing),
Damage to the wheat crop in Syria, to direct feeding typically range between 50 Potential to produce grain with protein
where nearly the whole harvest in a relatively and 90 percent. content in a given range (either high or low),
small area was affected, caused a loss of 24 Secondly, five nymph generations feeding
Grain hardness,
million Francs in 1924. The affected area on the ear of the plant have completed their
Potential to produce grain having a high
doubled in 1925 and was six-fold in 1926, larva era, but are still not mature insects
milling yield (high milling release),
but damage decreased in 1927 and 1928, or the young bugs increase the rate and
although the insect damage covered a larger number of bitten kernels, which in turn Resistance to weather damage-dormancy.
area. Part of Ukraine also suffered severe result in a sharp decline in the quality of
damage in 1901 and 1909. In Turkey, insect bread.
damage to wheat, first time, was reported If immature grain is attacked in the field Table 2: Seasonal Quality Attributes
in 1932 and 1937. The damage caused by by insects, there is damage to the mature Soundness and maturity,
bugs to the New Zealand crop is usually low, grain. The dough made from this grain is
Plumpness and hence actual milling yield,
but its incidence varies from year to year. very weak, owing to the action of a protease
There have been five major outbreaks of bug presumably injected by the insect. Because Actual protein content,
damage in New Zealand, since the problem of the severe results on dough formation Weather damage,
was first reported in 1936. The problem and baking quality, bug-damaged grain is Content of broken, shriveled, dry green, or
regained importance after the 1980s in severely downgraded, generally warranting frosted grains,
Afghanistan, Iran, Iraq, Syria, Russia, Bulgaria, only feed grade prices (Wrigley and Batey, Contamination of foreign seeds,
and Romania as well as in Turkey (Lorenz. 2003; Trissi, 2006). Presence of unmillable material, e.g. chaff,
and Meredith, 1988). In recent years, it has The damage caused by the cereal bug white heads,
reappeared in Black Sea region. shows important differences which are influ- Presence of moldy, insect damaged, or
The insects which cause the damage have enced by a number of criteria such as cli- infested grain,
been identified a Eurygaster integriceps and mate and weather conditions, availability of Moisture content.
Aelia rostrata in Europe and in the Near East. water, characteristics of the wheat type, and
22 | September - october 2012 Grain &feed millinG technoloGy

3. FEATURE
thus treated with pesticides. The calculated
cost for the treatment of one acre with
pesticides is about US$10, making a total of
US$5,870,000.
In a report prepared by specialists about
the cereal bug problem in Turkey, it was
stated that should no plant protection meas-
urement and precautions be taken against
the insect during plague years, the damage
could reach a ratio of 90 percent to as much
as 100 percent. Moreover, if sufficient pre-
cautions are taken against the plague, savings
with an amount of US$40,000,000 could be
achieved (Kınacı, 1994).
Varietal susceptibility
Many researchers have noted that the
genetic quality of the insect-damaged vari-
ety influences the degree of quality dete- and the soft type breeding line WW378 is much less (Kınacı, 1994).
rioration (Cressey et al, 1987). Paulian and was clearly the most susceptible to Nysius
Popov (1980) reported that hard wheats infestation. Effects on baking quality
are attacked more severely by the insect E. A similar study performed in Turkey by In 1931, wheat producing a ‘slimy gluten’
integriceps than soft wheats. Kınacı (1994) has proven that the cereal bug was reported by Berliner. This wheat was
Also, in New Zealand, the semi-hard E. integriceps prefers to attack white, soft completely unsuitable for processing into
wheat cultivar Karamu has shown more and/or semi-hard wheats and it is astonish- bread because doughs formed from the flour
effects and the soft, white wheat cultivar ing that the first priority of the insect is to quickly relaxed, becoming very sticky and
Arawa has fewer effects of bug damage than select those high quality kernels. The same difficult to mould.
other cultivars (Every et al, 1996). In a study study showed that E. integriceps rarely attacks Loaves of bread baked from these doughs
to investigate the susceptibility of various hard wheats. The latest genotypes of wheat typically had low volume, coarse texture, and
New Zealand wheat cultivars and breed- which the bug preferred to attack were hard knobbly tops. Gluten was washed out of the
ing lines to attack by N. huttoni, Every et al red wheats. Also it was observed that the flour with difficulty, and instead of having the
(1996) stated that the hard wheat cultivar density of the cereal bug among wheat hav- normal elastic properties; it was ‘slimy’ or
Domino was clearly the least susceptible ing thick, hard and tightly adhered seed coats ‘rotten’ (Lorenz and Meredith, 1988).
Grain &feed millinG technoloGy September - october 2012 | 23

4. FEATURE
Dough made from flour stinkbug-damaged
wheat has lost much of its elasticity and is
sticky or slimy.
A review of several overseas studies
(Nuorteva and Veijola, 1954) indicates that
in general a level of two to five percent
affected grain is necessary before baking
quality is degraded.
Meredith (1970) claimed that three to
four bug-damaged grains per thousand could
seriously affect baking quality.
Effects of attack by suni bug were studied
on the size of Russian grains and percent
of damaged grain was found to be higher
in smaller fractions; the proportion of fully
Figure 1. Farinogram, based on Brabender Farinograph Standard destroyed grains and the degree of damage
Procedure, shows 2.6% insect damage on wheat on the whole sample set both increased in
Courtesy of DORMAR Flour Mills, Turkey. smaller fractions (Yakovenko, 1985).
The influence of wheat infestation by suni
bug on bread making properties of Bulgarian
wheat was investigated and results showed
that suni bug infestation had a marked impact
on bread making properties, with even one
percent infestation affecting bread quality
(Vasileva et al., 1998).
Methods for the prediction of
damage
Physical Tests - Currently, the most widely
used method to determine insect damage
in wheat is the visual method. Wheat bug
damage to wheat kernels can be examined
visually since they are recognised as pale,
Figure 2. Extensigram, based on Brabender Extensigraph Standard slightly elevated patches, often with one or
Procedure, shows 2.6% insect damage on wheat more black dots considered to be the marks
Courtesy of DORMAR Flour Mills, Turkey. of bug stylet punctures. No such damage
can be found in uninfested samples.
Chemical and Biochemical Tests - The
prediction of the extent of insect-damage
to wheats prior to milling has gained impor-
tance as the enzyme secreted by cereal bugs
results in the production of runny and sticky
dough and, subsequently, a low quality of
bread.
Most of the test methods determine
the quality of gluten and dough, since the
enzyme influences the gluten structure.
Figure 3. Alveogram, based on Alveo-AH Standard Procedure shows
To determine the bug damage in wheats,
insect damage on wheat
Courtesy of POLEN Gıda, Turkey. Greenway et al (1965) developed a method
which is based on wheat sedimentation test.
The method has been found to be effective
and sensitive when two hydration times, such
Initially it was not known whether slimy Although puncture marks on wheat sug- as five and 180 minutes, were used.
gluten was produced by a new kind of gested attack by sap-sucking insects, the Atlı et al (1988) modified this method
wheat or by normal wheat that had been ability of affected wheat to ruin sound grain by applying a two-hour hydration period
damaged in some way. Whatever the cause indicated that slimy gluten was caused by after the addition of bromphenol solution
of the problem, it was clearly of considerable an enzyme. Two insects of the genera (Table 3, 4).
concern to European millers. Eurygaster and Aelia were considered to be In New Zealand, Cressey and McStay
According to later investigations, wheat that responsible for producing wheat with dam- (1987) proposed an autolytic assay method
produced slimy gluten had a proportion of grains aged gluten (Kretovich, 1944; Lorenz and that is based on the decrease in SDS-
with small dark puncture marks surrounded Meredith, 1988). sedimentation volume of bug-damaged
by a patch of lighter colour. Wheat without Brooke (1936) states that as little as one flours by incubating in distilled water for 30
puncture marks gave ‘sound’ gluten even if or two percent of stinkbug-damaged kernels minutes at 37oC. It has been suggested that
the grain was selected from a batch produced may injure the baking quality of wheat, the method is specific for bug damage and is
‘slimy’ gluten. However only relatively low levels depending on the severity of the damage in free of interference from other grain defects
(approximately 3%) of puncture-marked wheat the damaged kernels. Much larger quantities such as heat damage, field sprouting and
were needed to ruin the remaining sound grain of damaged kernels are often found in wheat laboratory germination.
(Lorenz and Meredith, 1988). from fields where the infestation was heavy. However, this method needs considera-
24 | September - october 2012 Grain &feed millinG technoloGy

5. FEATURE
instru-
Table 3:
ments.
‘Suni Bug It has
Wheat Type Sed., cc Del. Sed., cc
Damage’, % been sug-
gested
Bezostia 0.7 48 65 that it is
necessary
Mix 1.1 35 41
to record
White-Red 2.3 22 9 the farino-
White-Red 2.4 38 10 grams and
White 2.5 20 10 alveograms
immedi-
Courtesy of DORMAR Flour Mills, Turkey
ately after
the dough
Table 4: is made
Sedimentation Value, cc Gluten Quality
and again after it has
stood in a warm place
for 60 to 90 minutes,
<25 Weak as the disintegration
25 – 30 Medium of the dough takes
place only after it has
>30 Good
rested. Farinograph North America
curves of flour show
ble amount of sample and enzyme (Swallow the effects of bug
and Every, 1991). In addition, there is no damage particularly at
available information that this method can be higher temperatures
also used to detect the damage of Eurygaster (45oC). The curve of
and Aelia, since it has been developed for a sound flour is wider
different type of bug-damage. and the decrease in
Every (1991) developed an economical consistency with mix-
and sensitive SDS-protein gel method, based ing occurs less rapidly.
on the determination of enzyme activity, to The increasing soften- Asia Europe
test the activities of different protease types. ing of the dough also
This method measures the reduction in the shows as an irregular
gel-formation capacity of glutenin proteins by band towards the end
the enzyme. However, it is not known yet of the curve (Lorenz
if this method can be used for the damage and Meredith, 1988).
caused by Eurygaster and Aelia. According
The methods based on the washing of to Brabender
gluten after a resting period of 30 minutes Procedure; do the
at 25oC of the dough gives a better under- normal Farinogram
standing of changes in the quantity and qual- for 10 minutes, stop
ity of gluten (Atlı et al., 1988). the mixer (via soft-
Gluten index method also has been ware) (value here
found to be useful in determining the pres- is for example 480
ence of slimy gluten, due to the attack of BU), leave the dough Our grain storage systems
wheat kernels by wheat bugs (Perten, 1989). in the mixer, and
A method for rapid indication of infec- restart via software come with six continents
tion was proposed involving incubation of after 20 minutes
wheat in water at 30oC, to activate the insect pause. If the values of experience.
proteinases, followed by PAGE to determine of the second mixing Westeel offers a full line of professionally engineered grain
gluten profile and thus, the amount of deg- continue on the level storage products and systems for international sale – all
radation that has occurred (Corbellini et al., from the first mixing backed by Westeel’s superior service and product support.
2001). (around 480 BU in ƒ Commercial Grain Storage Bins (up to 674,000
this example), there bushels/18,343 tonnes)
Rheological Tests is no bug damage. If ƒ On-Farm Grain Storage Bins (starting from
2,390 bushels/65 tonnes)
Insect bug damage could be reliably the values are lower
ƒ Aeration Systems
predicted by using Brabender Farinograph, (for example total 50
ƒ Bin Unload and Grain Handling Systems
Brabender Extensigraph, and Chopin BU), there is strong
ƒ Systems Engineering and Design
Alveograph and Chopin Mixolab instruments. bug damage. From
For the estimation of the bug-damage, the second mixing,
another method which has been developed the bug damage in
in France uses Chopin extensimeter and the sample could be
has been made official by special regulation estimated (Figure 1).
P.O. Box 792, 450 Desautels Street Winnipeg,
(Kretovich, 1944). The Brabender
Manitoba, Canada R3C 2N5 Tel: (204) 233-7133
Kretovich (1944) indicated that bug dam- Extensigraph is Fax: (204) 235-0796 westeel@westeel.com
age could be reliably predicted by using another instrument
Brabender farinograph and Chopin alveograph used to determine westeel.com
Management Systems Registered to ISO 9001:2008. MF21589-0112
Grain &feed millinG technoloGy September - october 2012 | 25
21589 Westeel International 2012 G&FMT.indd 1 1/11/12 5:03:02 PM
Westeel: International 2012

6. FEATURE
Bread making Test Cleaning-tempering
In spite of the availability of Dıraman et al (2001) studied the
many methods developed for effect of steam tempering on some pro-
the prediction of Eurygaster and tein fractions and farinogram values of
Aelia damage to wheat quality, commercial wheat having sunn pest dam-
the most reliable and sensi- age at several levels. The evaluation of
tive method is a bread making farinogram data combined with positive
experiment. changes in protein fractions show that
However, there is still need 70oC temperature applied during steam
for simple and fast routine tests, tempering did not cause any negative
which can be used by the millers changes in rheological properties of sunn
during the purchase of wheat, pest damaged samples.
since the baking experiment is Köksel et al (2002) investigated mitigation
insect damage in wheat due to two or three relatively time-consuming. of the detrimental effects of suni bug dam-
resting periods (45, 90 and 135 minutes) age to wheat by cleaning and washing prior
between dough resistance and extensibility Suni bug management to milling and by elimination of mill streams
measurements (Figure 2). The current strategies for suni bug of lower quality. They concluded that ˃50
Currently, the Chopin Alveograph is also used management rely mainly on chemical and percent of insect-damaged kernels can be
for the measurement of insect-damage to wheat. cultural controls; in most cases, chemical removed by dry and wet cleaning prior to
The method involves testing of three dough control is the primary means of manage- milling and that flour streams with minimal
pieces out of five after resting 20 minutes and ment. This is a costly and unsuitable means insect damage can be selected.
after three hours for the remaining dough pieces. of pest management and has resulted in
It has been claimed that this method could detect resistance of suni bug to various types of Milling
about 0.9% insect damage by measuring the insecticides. Bogdan (1969) reported that bread of
reduction in P, L, and W values (Anonymous). The current novel management studies good quality can be produced from flour of
Since the enzyme delivered by insect involve the use of resistant wheat varieties, bug-damaged cereals when flour from dam-
needs time and temperature to show its insect pathogens, predators, parasites, and aged grains is blended with good quality flour,
effect, standard alveograph method, which parasitoids. Among the most promising of ascorbic acid and yeast are added in adequate
uses 20 minutes resting time, does not show these natural controls are the egg parasitoids amounts, or intensive kneading is applied.
the presence of insect-damage. However, (Trissi, 2006). According to Valtadoros (1979), by using
modified Alveograph method shows the Cereal growing, especially wheat, in mar- air classification, flour from bug-damaged
effect of insect damage since it uses extend- ginal lands; overgrazing of rangeland which wheat may be separated into fractions suit-
ed time of three hours - degradation test. results in the destruction of natural vegeta- able for bread making and those suitable for
The degradation test protocol involves: - a first tion and hence habitat of sunn pest preda- biscuit manufacture.
series of alveograph tests after 20 minutes of rest tors; reduction in the area of fallow land by
(ISO 5530/4, ICC121, AACC54-30 approved the continuous growing of cereals instead of Bread making
method) - a second series of balls of dough increasing food or forage legumes within a The effect of insect damage on bread
is tested after three hours rest. If the wheat rotation; the use of broad spectrum insecti- making quality of wheat depends on degree
contains bugs, a drop in baking strength (W) is cides, especially by aerial spraying, might also of damage or ratio of infested kernel and
observed due to protein hydrolysis caused by the have increased the difficulties of controlling quality of infested wheat.
insect’s proteolytic enzymes (Figure 3). the sunn pest problem in Turkey (Kınacı et In case of less than average five per-
It has been claimed that this method could al.,1998). cent damage and good protein quality and
detect about 0.9% insect damage by measur- quantity, effect of insect damage in wheat
ing the reduction in P, L, and W values. Improvement of bread quality flour could be lessen by using, improvers,
Atlı et al (1988) suggested a modification There are various studies on to improve the additives such as ascorbic acid (Bogdan,
of this method by using a two-hours resting quality of insect damaged wheats and their flours. 1969), vital wheat gluten, transglutaminase
period for the dough pieces. (Köksel et al., 2001), DATEM, etc. and
Aspesteguia et al (2003) reported that Wheat treatments modified methods such as short fermenta-
kneading temperature did not influence glu- In the USSR, high-frequency heating was tion (Swallow and Cresley, 1987), use of
ten degradation; however, resting tempera- used for treatment of wheat infested with sour dough procedure, etc (Dizlek and Gül,
ture significantly influenced when assessing the shield bug and recommended as a meas- 2007).
wheat damaged by wheat bugs. ure for restitution of the baking performance
The Chopin Mixolab system measures of deteriorated grain (Pruidze et al, 1984). Conclusion
real-time dough behaviour with regard to Dıraman (2010) investigated the effects The suni bug is one of the most serious
the dual constraint of kneading and tem- of microwave treatment on technological pests of wheat in Europe (except north-
perature. and rheological properties of flours produced ernmost areas), North Africa and Asia.
It is claimed that system measures insect from sound wheat and wheat damaged by Yield loss from its damage is commonly
damage in 45 minutes including rest time. sunn pests (Eurygaster spp.). The results estimated at 50-90 percent in wheat and
Investigations were conducted on the for Zeleny sedimentation, Gluten Index and heavy attack causes wheat stems to break
development of a rapid method (using alveogram values suggest that certain micro- before harvest.
viscosity measurement with the Rapid Visco wave treatment times (120-180 seconds) Even if two to three percent of the grain
Analyzer) for testing wheat for proteolytic caused positive effects on thermal inactivation is damaged, entire lots may be unsuitable for
determination due to infestation with insects of insect enzyme damage of wheat. bread making. Therefore, there is a need
of the genera Aelia and Eurygaster. for simple and fast routine tests, which can
Results showed that this method is rapid Blending be used by the millers during the purchase
(results within 10 minutes) and gives 97.27% Wrigley and Batey (2003) stated that of wheat, since the baking experiment is
correct classification over a wide range because of the involvement of enzymatic relatively time-consuming.
of proteolytic degradation. Repeatability action, the effects of mixing bug-damaged
and reproducibility were good (Caballero- grain with sound grain are disproportionate to References
Barrigon and Perez-Calvo, 2008). the proportions of samples mixed. Available on request
26 | September - october 2012 Grain &feed millinG technoloGy

7. Europe & International Uncoated Fine Paper Corrugated Bags & Coatings
Reap the Benefits!
Customised industrial bags for quick filling and
ative Farming & Food Industry protection of your filling goods.
reliable Household Industrial Medical & Office & Pet
ustry Agriculture Industry Paper & Packaging Pharmaceutical Printing Paper Ind
Industry Industry Industry Industry
ng
r presenti
Window fo ly
goo d attractive
the filling
le dosage
and simp
2
Hygienic
1 chniques
closure te
6
Reliable
through
protection
sealab le valves
4 r 5
3 able Suitable fo
Compact Compost
ith contact
d imensions bags w food
able film
biodegrad
SOLUTIONS.
FOR YOUR SUCCESS.
www.mondigroup.com

8. Milling Technology magazine.
Content from the magazine is available to view free-of-charge, both as a full
LINKS
This digital Re-print is part of the September | October 2012 edition of Grain & Feed
online magazine on our website, and as an archive of individual features on
the docstoc website.
Please click here to view our other publications on www.docstoc.com.
September - October 2012 • See the full issue
• A packaging
evolution
In this issue:
• Visit the GFMT website
• Insect
damaged
• Contact the GFMT Team
• Pellet production wheat:
to save energy, improve feed suni bug, cereal
efficiency and safety bug, sunn pest,
wheat bug, shield
bug, shell bug
• Managing mill
maintenance
• Probiotics: • Global
• Subscribe to GFMT
modulators of gut bacteria grain & feed
dialogue
markets
We have interactive
content in this edition
that requires a smart
phone app - get it
here for free to unlock
our digital content!
A subscription magazine for the global flour & feed milling industries - first published in 1891
To purchase a paper copy of the magazine, or to subscribe to the paper edi-
tion please contact our Circulation and Subscriptions Manager on the link
adove.
INFORMATION FOR ADVERTISERS - CLICK HERE
Article reprints
All Grain & Feed Milling Tecchnology feature articles can be re-printed as a 4 or 8 page booklets (these
have been used as point of sale materials, promotional materials for shows and exhibitions etc).
If you are interested in getting this article re-printed please contact the GFMT team for more informa-
tion on - Tel: +44 1242 267707 - Email: jamest@gfmt.co.uk or visit www.gfmt.co.uk/reprints
www.gfmt.co.uk