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Egg Removal Device for the Management of Three Stored Product Pests.

  • Directorate of Plant Protection Quarantine and Storage

Abstract and Figures

nvestigations were carried out to assess the efficiency of pulse beetle egg removal device (TNAU Patent, 198434) in the removal of eggs of Tribolium castaneum and Rhyzopertha dominica from infested sorghum, wheat, maize and paddy grains and the eggs of Lasioderma serricorne from infested coriander. The efficiency of the device or the physiological impact of rotation was assessed based on the number of offspring adults emerged and percentage reduction in adult emergence over control. Rotation of the grains for three consecutive days @ 15 min/day gave good control in suppressing the emergence of offspring adults. A reduction in emergence of T. castaneum and R. dominica were found to be 54 and 57% in sorghum; 69 and 69% in wheat; and 71 and 76% in maize, respectively. A maximum reduction of 76% adults of R. dominica was observed in paddy.
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10th International Working Conference on Stored Product Protection
Egg removal device for the management of three stored product pests
Jayaprakash, S.A.*#, Mohan, S., Ramaraju, K.
Department of Agricultural Entomology, Tamil Nadu Agricultural University, Coimbatore - 641 003, India.
* Corresponding author
# Presenting author
DOI: 10.5073/jka.2010.425.318
Investigations were carried out to assess the efficiency of pulse beetle egg removal device in the removal of
eggs of Tribolium castaneum and Rhyzopertha dominica from infested sorghum, wheat, maize and
grains and the eggs of Lasioderma serricorne from infested coriander. The efficiency of the device or
the impact of rotation was assessed based on the number of offspring adults emerged and
reduction in adult emergence compared to untreated controls. Rotation of the grains for three
days for 15 min/day gave the highest reduction in the emergence of offspring adults.
Reductions in
emergence of T. castaneum and R. dominica were found to be 54 and 57% in sorghum; 69 and 69% in wheat;
and 71 and 76% in maize, respectively. There was a 77% reduction in L. serricorne on coriander seed, and a
similar level for R. dominica on paddy.
Keywords: Pulse beetle egg removal device, Tribolium castaneum, Rhyzopertha dominica, Lasioderma
1. Introduction
The stored grains are attacked by more than a dozen of stored grain insect pests (Simwat and Chahal,
1982). They assume greater importance as they start their damage in the field itself (Mohan and Subba
Rao, 2000). Generally stored-product insects fly from nearby farms, farm store houses or farmer
storehouses and start laying eggs on the maturing grains. So eggs are the basic root in causing damage to
the grains during storage. Synthetic insecticides, residual and fumigants, are widely used to control
insects in stored grain. However, there are number of reasons people are seeking alternatives to chemical
insecticides; concerns over worker and consumer safety, the development of insecticide-resistant
populations and problems with the environmental damage, methyl bromide as an ozone depletor is an
example. Thus there is an interest in mechanical control methods, like removal of eggs from the grains
before storing. Physical or mechanical methods like rotation, tumbling and impact of infested grains are
an effective method of control for stored-product insect populations (Bailey, 1962; Joffe, 1963; Joffe and
Clarke, 1963; Bailey, 1969; Loschiavo, 1978; Ungsunantwiwat and Mills, 1979; Quentin et al., 1991;
Plarre and Reichmuth, 2000). Until now, only limited information was available in using the mechanical
mode for controlling the egg stage of insects. Hence, in the goal of this study was, to assess the
performance of the pulse beetle egg removal device in removing the eggs of red flour beetle, Tribolium
castaneum (Herbst), the lesser grain borer, Rhyzopertha dominica (F.) and the cigarette beetle,
Laisoderma serricorne (F.) from various food grains.
2. Materials and methods
2.1. Insects
The test insects used for the various experimental studies were, the T. castaneum, R. dominica and L.
serricorne. They were mass reared in plastic containers in the laboratory. Sorghum grains infested with
T. castaneum were collected from Millet Breeding Station, Tamil Nadu Agricultural University,
Coimbatore, India, and were cultured on whole wheat flour at 30
C and 70% r.h. (White, 1982).
Sorghum grains infested with R. dominica were collected from Millet Breeding Station, Tamil Nadu
Agricultural University, Coimbatore, India, and were reared in the laboratory at 28oC and 70% r.h. on
organic whole wheat kernels (Mohan et al., 2007).Coriander, turmeric powder and chili powder which
were infested with L. serricorne were collected from local markets for initiating culture. During storage,
whole coriander is infested by cigarette beetle causing considerable damage and deteriorates the quality
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(Agrawal and Srivastava, 1984). The insects were reared at 27 ± 1°C and 60 ± 5% r.h. with a 12 h
photoperiod on a diet of whole wheat flour (10 parts), white cornmeal (10 parts), and brewers‘ yeast (1.5 parts)
(Arbogast et al., 2003).
2.2. Pulse beetle egg removal device
Egg removal device for pulse beetle (Mohan, 2005) was used to assess the efficiency of its egg removal
against other important stored-product insects namely, T. castaneum, R. dominica and L. serricorne. The
device comprises of an outer container enclosing an inner perforated container (Fig. 1). The outer
container (18.5 cm high and 21 cm diameter) was made of aluminum and the inner perforated container
made up of galvanized iron sheet with a diameter of 15 cm. The outer container and inner perforated
container (3 mm perforations) were arranged in such a manner that a gap of 3 cm exists between them.
The containers were provided with a lid at the top, the lid having an opening at its centre. A rotatable rod
is provided with smooth brushes of length 4.5 cm fixed equispaced (Fig. 2). The sides of brushes touch
the inner walls of the inner perforated container. The rotatable rods are fixed to the bottom of the inner
container and pass through the opening, connecting the lid at the top. The other end of the outer container
is provided with a transparent container to collect the insects which fall down from the inner perforated
Figure 1 Outer view of pulse beetle egg removal device .
Figure 2 Inner view of pulse beetle egg removal device.
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2.3. Efficiency of egg removal device
Sorghum and maize grains were obtained from the Millet Breeding Station, Tamil Nadu Agricultural
University, Coimbatore, Tamil Nadu, India and the paddy grains were procured from Paddy Breeding
Station, TNAU, Coimbatore, Tamil Nadu, India, whereas, wheat grains were obtained from Horticultural
Research Station, Ooty, Tamil Nadu, India. The grains were sieved to remove dust and insects and then kept
at -18oC in 1 kg batches sealed in polythene bags for 10 d to destroy any prior infestation by insects (Shazali
and Smith, 1986).
Unsexed adults of T. castaneum and R. dominica were released inside the grains of sorghum, wheat,
maize or paddy (T. castaneum was not used for paddy) at the rate of 100 adults into 1 kg of grain. The
grains were placed in plastic containers, covered with cloth. The grains were kept as such for 7 days for
ovipositon at room temperature (26 - 27oC). After 7 d, adult insects were sieved from the grain (1 kg)
and the grains were placed in the inner perforated container of the egg removal device (Fig. 2). Circular
rotation involving clockwise and anticlockwise movements in an alternate manner were done for 15 min.
once a day. There were 3 treatment levels; seeds were rotated for 1, 2 or 3 consecutive days.
The grains were taken out and kept undisturbed for a period of 40 days to allow for the development and
emergence of offspring adults. The offspring adults were removed three times between 40 and 60 d and
the all adults from these three sievings were totaled to give the number of offspring adults for each
Coriander were obtained from local groceries and were sieved to make it free from dust and insect stages
if any and it was disinfested as above by freezing. Likewise, for assessing the performance of the device
in the removal of eggs of L. serricorne from coriander, the same methodology stated earlier was
2.4. Statistical analysis
The data pertaining to the observations in the laboratory were transformed using square root
transformation and then analyzed in a Completely Randomized Design (CRD). The mean values of the
experiments were separated using Duncan‘s Multiple Range Test (Gomez and Gomez, 1984).
3. Results
There were very similar results for all insects on all grains. A single rotation for 15 min on day one reduced
populations from 16 to 37% compared to controls, 2 days of treatment reduce populations from 37 to 67% and 3
days of treatment reduced populations the greatest amount, with declines of 54 to 77%. There was a regular
decrease in the population with each progressive day of treatment, with populations decreasing on average 15 +
3% per day. Mechanical damage observed was very meager in the test grains when they were subjected
to rotational impact.
Table 1 Impact of egg removal device on the egg stage by way of assessing the emergence of Tribolium
castaneum and Rhyzopertha dominica adults from infested sorghum and wheat grains.
Sorghum Wheat
T. castaneum R. dominica T. castaneum R. dominica
Adults Adults Adults Adults
Days emerged Reduction emerged Reduction emerged Reduction emerged Reduction
treated Mean ± SE (%) Mean ± SE (%) Mean ± SE (%) Mean ± SE (%)
537 ± 12.3
0 671 ± 4.1 d d 705 ± 5.5 d 612 ± 6.7 d
1 508 ± 6.0 c 24 441 ± 8.3 c 17 587 ± 10.3 c 16 437 ± 7.2 c 28
2 419 ± 4.2 b 37 304 ± 5.6 b 43 420 ± 5.4 b 40 316 ± 11.3 b 48
3 306 ± 8.2 a 54 230 ± 8.6 a 57 218 ± 4.4 a 69 187 ± 5.3 a 69
(P = 0.05) 0.4471 0.6998 0.4654 0.6587
CV% 1.54 2.72 1.61 2.55
Means followed by the same letter are not significantly different, Duncan‘s Multiple Range Test (P < 0.05), n=5.
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Table 2 Impact of egg removal device on the egg stage by way of assessing the emergence of Tribolium
castaneum and Rhyzopertha dominica adults from infested maize and paddy grains.
Maize Paddy
T. castaneum R. dominica R. dominica
Adults Adults
Days emerged Reduction Adults emerged Reduction emerged Mean Reduction
treated Mean ± SE (%) Mean ± SE (%) ± SE (%)
0 593 ± 9.0 d 517 ± 7.3 d 687 ± 6.8 d
1 498 ± 13.6 c 16 432 ± 9.8 c 16 502 ± 10.3 c 26
2 364 ± 7.6 b 38 302 ± 6.9 b 41 364 ± 13.4 b 47
3 169 ± 5.4 a 71 123 ± 5.0 a 76 161 ± 13.1 a 76
CD (P =
0.05) 0.6859 0.6284 1.0205
CV% 2.60 2.60 3.79
Means followed by the same letter are not significantly different, Duncan‘s Multiple Range Test (P < 0.05), n=5.
Table 3 Impact of egg removal device on the egg stage by way of assessing the emergence of Lasioderma
serricorne adults from infested coriander seeds.
Days Adults emerged Reduction
Treated Mean ± SE (%)
0 116± 10.3 c
1 72 ± 2.6 b 37
2 38± 2.2 a 67
3 26 ± 3.1 a 77
CD (P =
0.05) 1.2498
CV% 8.86
Means followed by the same letter are not significantly different,
Duncan‘s Multiple Range Test (P < 0.05), n=5.
4. Discussion
Brushing infested seed had a dramatic reduction in insect populations, with control being over 70% after three
consecutive days of treatments. Generally, the females of L. serricorne and T. castaneum oviposit
directly on
the surface of grains, and R. dominica laying eggs both inside and outside the kernels
(Ashworth, 1993;
Rees, 2004). Also young larvae of the insects are free living, starting on the outside of the seed, before finding
cracks in the grain to establish themselves. This is contrast to the Sitophilus spp. that lay their eggs in the grain
and larvae complete their life cycle inside the kernel. Brushing the seed could control populations by removing
or destroying eggs or young larvae.
The regular bean tumbling dramatically lowered the bean weevil Acanthoscelides obtectus (Say)
populations by approximately 97% in kidney bean (Phaseolus vulgaris L.) (Quentin et al., 1991). The
mortality of rusty grain beetle Cryptolestes ferrugineus (Stephens) adults generally increased with
increasing number of drops in wheat (Loschiavo, 1978). Joffe and Clarke (1963) working in elevators, showed
that the type, timing and frequency of disturbance played a significant role in determining the extent of
damage to Sitophilus oryzae (L.). They reported that the daily disturbance of maize grains resulted in a
higher percentage of control of S. oryzae
Future experiments could examine if more frequent rotations or longer duration of rotations would affect
mortality. Other experiments could examine if complete control can be obtained by rotating the grain for
every day for 4, 5, 6 or 7 days. In this study both eggs and first instar larvae were be present.
Experiments with a more well defined age structure would determine if there are differences in
susceptibly between, eggs, first instar larvae, late instar larvae, pupae and adults to this type of control.
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We thank Paul Fields, Agriculture and Agri-Food Canada for encouragement and support.
Agrawal, R.K., Srivastava, J.L., 1984. Storage losses in coriander (Coriandrum sativum) by Lasioderma serricorne
(Fabr). Bulletin of Grain Technology 22, 183-185.
Arbogast, R.T., Kendra, P.E., Chini, S.R., 2003. Lasioderma serricorne (Coleoptera: Anobidae): Spatial
relationship between trap catch and distance from an infested product. Florida Entomologist 86, 437-444.
Ashworth, R.J., 1993. The biology of Lasioderma serricorne. Journal of Stored Product Research 29, 291-303.
Bailey, S.W., 1962. The effects of percussion on insect pests of grain. Journal Economic Entomology 55, 301-310.
Bailey, S.W., 1969. The effects of physical stress in the grain weevil Sitophilus granarius. Journal of Stored
Product Research 5, 311-324.
Gomez, K.A., Gomez, A.A., 1984. Statistical Procedures for Agricultural Research. John Wiley and Sons, New
Joffe, A., 1963. The effect of physical disturbance or ―turning‖ of stored maize on the development of insect
infestations. Grain elevator studies. South African Journal of Agricultural Science 6, 55-64.
Joffe, A., Clarke, B., 1963. The effect of physical disturbance or ―turning‖ of stored maize on the development of
insect infestations. Laboratory studies with Sitophilus oryzae (L.). South African Journal of Agricultural
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Loschiavo, S.R., 1978. Effect of disturbance of wheat on four species of stored product insects. Journal Economic
Entomology of 71, 883-893.
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Stored-Product IPM. Kluwer Academic Publishers, Boston, USA, pp. 401-428.
Mohan, S., Sivakumar, S.S., Venkatesh, S.R., Raghavan, G.S.V., 2007. Penetration of polyethylene sheets coated
with protein-enriched pea flour solution by two stored-product insects. Journal of Stored Product Research
43, 202-204.
Mohan, S., Subba Rao, P.V., 2000. Field record of Callosobruchus chinensis L. infesting black gram, Vigna mungo
(L.) Hepper and green gram, Vigna radiata (L.) Wilczek in Tamil Nadu. Bulletin of Grain Technology 33,
Mohan, S., 2005. A device to remove insect eggs from stored pulse seeds. Indian Patent No: 198434. The Patent
Office Journal. Issue No. 10/2005 dated 23.05.2005. pp. 12101.
Quentin, M.E., Spencer, J.L., Miller, J.R., 1991. Bean tumbling as a control measure for the common bean weevil,
Acanthoscelides obtectus. Entomologia Experimentalis et Applicata 60, 105-109.
Rees, D.P. 2004. Insects of Stored Products. CSIRO Publishing, Collingwood, Australia.
Shazali, M.E.H., Smith, R.H., 1986. Life history studies of externally feeding pests of stored sorghum: Corcyra
cephalonica (Staint.) and Tribolium castaneum (Hbst). Journal of Stored Product Research 22, 55-61.
Simwat, G.S., Chahal, B.S., 1982. Effect of different levels of initial infestation of Sitophilus oryzae L.,
Trogoderma granarium Everts and Tribolium castaneum Herbst on their population build-up and resultant loss of
wheat. Bulletin of Grain Technology 20, 25-30.
Ungsunantwiwat, A., Mills R.B., 1979. Influence of medium and physical disturbances during rearing on
development and numbers of Sitophilus progeny. Journal of Stored Product Research 15, 37-42.
White, G.G., 1982. The effect of grain damage on development in wheat of Tribolium castaneum (Herbst) (Coleoptera:
Tenebrionidae). Journal of Stored Product Research 18, 115-119.
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... Effectiveness was improved by spreading infested grain on a black polyethylene sheet, covering them with a sheet of translucent plastic and weighing down the edges with stones . During grain handling and storage, the physical control methods is defined as effective and alternative methods to pesticides to prevent and control pests (Jayaprakash et al., 2010). Studies on physical methods of pest management generally involved heat treatment and testing the effectiveness of solar radiation, although few studies also evaluated the role of oven heating. ...
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Postharvest losses and their management practices of Maize production in Ethiopia were overviewed. Agriculture is vital for addressing food security problems in Ethiopia. Agriculture contributes to overcoming the food security problem through growth that distributes its benefits as widely as possible by increasing production and productivity. About 30 to 50 per cent postharvest loss is because of inappropriate collection, transport, storage and pest control systems in Ethiopia were found tremendous for different cereal grains. The review was done by collecting the various published and unpublished materials relevant information from different literature sources like libraries, research report, journals, books and Internet center. Postharvest quantity and quality loss of cereal grains in developing countries appear to be initiated mostly at the farm level, so the potential solutions for the problem are needed at the same level. To minimize losses and increase the shelf life of the food grains which inhibit the growth of pests and provide proper storage facilities, appropriate packaging materials and transportation facilities are required. A corrective suggestion on suitable approaches to loss reduction in postharvest handling of maize grains was reviewed. As the result of review, it concludes that further studies are needed concerning physical, bio-chemical and socio-economic aspects at each production level.
... In India, the commercial model of insect egg remover is one of the recent inventions. The prototype models of insect egg remover were extensively tested, and their effectiveness were well established in removing adult stored product insects (Divya et al., 2009;Jayaprakash et al., 2010). The recent development of the commercial models of the abovementioned device (Mohan, 2011) made it necessary to thoroughly investigate their effect on stored grain insect eggs management (crushing) and consequently prevent grains damage so that they can directly be transferred to the end-users. ...
The side effects of pesticides and fumigants have led to the development of ecofriendly stored grains in insect management methods. Insect egg remover is one of the recent inventions to be used in the management of stored grain insects. The inner brushing arrangement in the device facilitates the crushing of the eggs, if any, in the grains. Investigations were made to determine the effectiveness of the insect egg remover for the management of stored grain insects. The number of times the grains passed in the device (one, two and three times) and the density of insects (10, 20 and 30) were the two factors of the experiment. After rotating the grains with eggs in the machine, they were incubated for 60 days for assessing progeny production and grains damage. The device proved effective in reducing the emergence of Rhyzopertha dominica (F) and Tribolium castaneum (Herbst) adults without the influence of the densities of insects artificially introduced in paddy and sorghum grains, respectively. The pattern of emerged adults was significantly less in three passes. In addition, the density of insects did not influence significantly the emergence of adults and grain damage. However, grains damage at 40 and 60 days of incubation was significantly affected by the number of passes in the device. The lowest damage was recorded in three passes and the highest damage was in untreated grains. Most farmers could benefit by using this mechanical device. The design of the device is such that it can facilitate in crushing eggs beside the rapid removal of adult insects from mild and severely infested grains and consequently prevent grains damage and eliminates the possibility of the pests developing resistance over time. However, the machine has the limitations of controlling only external feeding stored insects and this study recommends a cost-benefit analysis. [Fundam Appl Agric 2020; 5(3.000): 429-434]
... Farmers are seeking alternatives to chemical insecticides to meet such demands. Physical control methods have been described as effective and alternative methods to pesticides to prevent and control pests during grain handling and storage [13]. ...
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Sitophilus zeamais Motschulsky is the most important insect pest of stored maize in tropical regions. The objective of this study was to determine the practicality of periodic physical disturbance on S. zeamais mortality and its adoption by smallholder farmers in developing countries. In this experiment, treatments and control were arranged in a randomized block design with three replications and three storage times in three regions of Tanzania. Region was used as the blocking variable. A total of 108 clean 20-L plastic containers were each loaded with 10 kg of fresh white dent corn and 0.50 kg of maize infested with S. zeamais. For the treatment, containers were disturbed twice a day, whereas for the controls the containers were not disturbed until the end of storage. The overall mortality rate(%) after 30,60,and 90 days of storage were 88%,96%,and 98%,respectively. A statistically significant difference (p < 0.05) was observed for the number of live S. zeamais between the control and experimental treatments. Additionally, the number of live S. zeamais in the treatment significantly decreased as storage time increased. This study shows the potential of a feasible, simple, affordable, and effective method of protecting maize grain for small-holder farmers in developing countries without using chemicals
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Recognizing that it takes Acanthoscelides obtectus (Say) (Coleoptera: Bruchidae) larvae over 24 h to bore into a dry red kidney bean {Phaseolus vulgaris L.) and that boring can occur only at particular sites where a bean abuts some other surface, we postulated that this pest might be controlled by periodic tumbling of beans so as to place initiated holes out of register with requisite touching surfaces. Larvae repeatedly forced to initiate holes might die of exhaustion, if not smashed by tumbling beans. Indeed, brief daily tumbling of beans held in half-filled jars, buckets, and gunny sacks reduced A. obtectus populations by 97% relative to stationary controls. We recommend that small lots of beans can be protected indefinitely from the bean weevil when stored in <75% filled cylinders rolled ca 1 circumference every morning and evening. This control method should be immediately useful, particularly among subsistence families, since the only external input is knowledge. Also, this control principle might be broadly applicable to other bean and grain pests having strict spatial and temporal requirements for seed penetration.
A laboratory study of the ecology of single-species populations of C. cephalonica (Staint.) and T. castaneum (Hbst) was made on sorghum at three temperatures (25, 30 and 35°C) and three relative humidities (60, 70 and 80% r.h.). The effects of two lower humidities (40 and 50% r.h.) on both species were also studied at 30°C. The optimal conditions for multiplication of C. cephalonica were found to be 30°C and 60–80% r.h., while for T. castaneum the optimal temperature was 35°C at the same range of humidity. Lower humidities (40 and 50% r.h.) had a small adverse effect on both species. The results are compared with those of other workers and discussed in relation to the distribution of the two species in Sudan. It is concluded that the pest potential of C. cephalonica has been underestimated in the past.
Adults of Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) penetrated polyethylene sheets (0.0635mm thickness) coated with protein-enriched pea flour solution (water pH 8.5–9.0) at 0 (control), 1 and 5% levels, but did not penetrate the sheets coated with a 10% concentration. The potential of using protein-enriched pea flour in the manufacture of insect-proof factory impregnated plastic sheeting is discussed.
Four Sitophilus populations (Sitophilus zeamais Motschulsky from Mexico, S. zeamais from Arkansas, U.S.A., Sitophilus oryzae L., and Sitophilus granarius L.) were studied. Hard red winter wheat, sorghum, and maize were used to determine effects of rearing media on progeny production of insects from the four populations.Mechanically disturbing infested samples to remove newly-emerged adult weevils every 48 hr reduced numbers of progeny surviving to the adult stage, especially for Arkansas S. zeamais and S. granarius reared in any of the three grains.With one exception, reproduction for all populations in all three grains was highest when parents were reared in wheat; other differences are discussed. Also, progeny developmental periods for all four populations were shortest when parents were reared in wheat. Progeny of all four populations had the longest developmental periods when reared in maize regardless of the medium in which their parents were reared.In 250 g samples of wheat, and 125 g samples of sorghum, 50 parent S. oryzae produced statistically as many progeny as in 500 g and 625 g samples of wheat and 250, 500, and 625 g samples of sorghum, respectively. In maize, 625 g samples produced significantly more progeny than 500 g samples.Sex ratios of progeny from each grain were 1:1, except that females of S. oryzae reared in maize outnumbered males.
The effect of severity of grain damage on survival and development of larvae of Tribolium castaneum in wheat was investigated. Exposure of the germ was generally necessary for survival of young larvae. Rate of development increased with degree of exposure of the germ. Survival and development would not be significantly affected by a practicable reduction in the current level of grain damage in mechanically harvested wheat.
The effects of percussion on grain and on insect pests of grain have been examined. It was found that adults and unprotected immature stages of the granary weevil (Sitophilus granarius (L.)) were killed by a relatively small amount of impact forces. To kill immature stages living within the grains required the use of forces intense enough to cause excessive breakage of the grain. It is suggested that the survival of immature stages within the grain was caused by the physical support provided by the grain, which prevented severe flattening of the insect.
Wheat infested separately with 4 species of stored-product insects was subjected to physical disturbance by being dropped in small sacks or through a tube from a height of 14.1 m or rotated and tumbled. These impact forces did not damage kernels or impair germination. Mortality of adults and larvae of the rusty grain beetle, Cryptolestes ferrugineus (Stephens), and the red flour beetle, Tribolium castaneum (Herbst), increased with increasing disturbance. Adults of the granary weevil, Sitophilus granaries (L.) and rice weevil, S. oryzae (L.). suffered 96% mortality when dropped in sacks. About 5% mortality occurred when granary weevils were dropped with free-falling wheat, and 13% when rotated and tumbled in sacks. Rusty grain beetles sustained a higher mortality than the other species in free-falling wheat or sacks subjected to rotation and tumbling. Reproduction by red flour beetles that survived impact in free-falling wheat was not impaired. Emergence of adult F1 progeny in disturbed wheat was reduced for the rusty grain beetle but not for the granary weevil.
El escarabajo del cigarillo, Lasioderma serricorne (Fabricius), fue seleccionado como un representante de un escarabajo de productos almacenados para probar la validez de un mapa de contorno de los especimenes capturados en trampas para un monitoreo de los almacenes y tiendas comerciales. Se realizaron tres experimentos, cada uno con 5 réplicas, en un cobertizo de lauminio de 3.2 × 9.0-m. Cada experimento envolvia liberar los escarabajos en un solo punto y registrar en número capturados despué de 6, 24, y 48 h en cada una de las 14 trampas con cebo de caida “pitfall” distribuidas sobre en piso del cobertizo. Los experimentos variaron solamente con respeto del punto de la liberación.Los escarabajos fueron liberados en una manera pasiva de las cajas de cria puestos en uno de los tres puntos de liberación, y su dispersión fue rastreada usando mapas contornos consecutivos de los especimenes capturados en cada punto. Mientras que los escarabajos se disparsaron y el número total de los especimenes capturado aumentó, las trampas remotas capturaron progresivamente más insectos, pero el número acumulativo de los especimenes capturados en las trampas cerca de los puntos donde fueron liberados permaneció en más alto. La razón de la captura fue la más alto inmediatamente después de la liberación y bajó con el tiempo, rapidamente al principio y luego más despacio hasta que quedó casi constante. El número acumulativo de escarabajos capturados en cualquier trampa después de 6, 24, y 48 h bajó exponencialmente según la distancia del punto de liberación. Los patrons espaciales observados de los escarabajos capturados en las trampas en relacción de las fuentes de infestación y la relación inversa de los escarabajos capturados a la distancia de la fuente apoya la validéz de loos mapas contornos como un medio papa hacer un monitoreo de insectos de productos almacenados y localizar los focos de infestación.
A review detailing the biology of Lasioderma serricorne (Fabricius) including the morphology, development, trophic biology and reproduction of this insect is presented. Adults emerge from the pupal case sexually mature, and females can oviposit within a day of emergence. Eggs hatch within a week, the larvae burrowing down into the food, damaging tobacco by eating small galleries through the host material. Larvae pass through four instars and pupate within a cell made from food and waste material cemented together by midgut secretions. Although found on a wide variety of foodstuffs, the beetle is well adapted to developing on tobacco, with intracellular symbionts forming an integral part of the beetles' physiology. Details of the pheromonal stimulation of mating and both male and female behaviours are outlined, as are the predators and parasitoids of this insect.
It is shown that physical disturbance of wheat in which immature stages of the grain weevil, Sitophilus granarius (L.) are living, may prevent many or all of the insects developing successfully. Disturbance was particularly effective when carried out regularly, such as daily or twice weekly and even very small forces such as the impact due to the wheat falling only 23 cm had an effect. All the immature stages of the insect were susceptible to regular disturbance but the ‘pre-pupae’ and the pupae were most susceptible.The cause of death was examined and the possible roles of damage to the water-proofing layers of the cuticle and of some physiological functions were considered. The rates of water loss and oxygen consumption were measured and the effects, during disturbance, of carbon dioxide anaesthesia and of chilling were determined.