Changes in stored-wheat ecosystems infested with two combinations of insect species

1980 ◽  
Vol 58 (9) ◽  
pp. 1524-1534 ◽  
Author(s):  
N. D. G. White ◽  
R. N. Sinha

The consequences of infestation of bulk-stored wheat by multiple species of insects were determined for 60 weeks at 30 ± 2 °C. Eight 204-L drums containing wheat at 15.5% moisture content were used as three distinct systems: (I) Control system (two drums), insect free; (II) RST system (three drums), infested with the grouping of Rhyzopertha dominica F., Sitophilus oryzae (L.), and Tribolium castaneum (Herbst); and (III) COT system (three drums), infested with the grouping of Cryptolestes ferrugineus (Stephens), Oryzaephilus surinamensis (L.), and T. castaneum. At triweekly intervals carbon dioxide, oxygen, temperature, grain moisture, seed damage, grain weight, dust weight, fat acidity values (FAV), seed germination, microflora, and the numbers of insects and the mite Tarsonemus granarius Lindquist were measured. Seeds died by week 15 and bacterial infection on them increased in all systems. The seed FAVs in the RST system peaked by week 30 and then declined steadily while these values were increasing continuously in the Control and levelling off in the COT systems. Insects multiplied exponentially for 6–15 weeks and then declined sharply or maintained oscillating populations; Sitophilus and Oryzaephilus were unable to survive in the presence of the other insects.

Insects ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 151 ◽  
Author(s):  
Frank H. Arthur ◽  
Christos G. Athanassiou ◽  
W. Robert Morrison

Adults of Rhyzopertha dominica (F.), the lesser grain borer, Cryptolestes ferrugineus (Stephens), the rusty grain beetle, and Sitophilus oryzae (L.), the rice weevil, were exposed for 1, 24, and 72 h on wheat treated with concentrations of 0% (untreated controls) to 100% of the proposed label rate of an experimental formulation of deltamethrin + Methoprene + piperonyl butoxide synergist. Movement and velocity of movement were assessed after each exposure time using a camera-based monitoring system (Ethovision®). Movement of R. dominica decreased with increasing concentration and exposure time, so that movement had virtually ceased at the 48 and 72 h exposures. Cryptolestes ferrugineus was less susceptible compared to R. dominica, but there was still a general pattern of decreased movement and velocity of movement with increasing concentration and exposure time. Sitophilus oryzae was the least susceptible species, with less differences at the 1 h exposure interval compared to the other two species, but after 24–72 h, the patterns of declining movement and velocity were apparent as the concentration increased. Data were analyzed using curve-fit equations to show the relationship between concentration and exposure time for each species. Results show that the Ethovison system can be used to assess the sub-lethal effects of exposure to grain protectant insecticides and elucidate behavioral variation between different stored product insects.


1987 ◽  
Vol 27 (2) ◽  
pp. 309 ◽  
Author(s):  
JM Desmarchelier ◽  
JC Dines

The efficacy of Dryacide (diatomaceous earth coated with silica aerogels) on wheat was tested in the laboratory against adult and immature stages of 4 species of Coleoptera and against immature stages of 1 species of Lepidoptera. The minimum effective level of Dryacide increased in the following order: immature Ephestia cautella (Walker) ~ immature Tribolium castaneum (Herbst) < immature Rhyzopertha dominica (F) < adult R. dominica ~ adult T. castaneum < adult Sitophilus oryzae (L) < adult Sitophilus granarius (L) < immature Sitophilus species. When wheat treated with Dryacide was milled in the laboratory without prior cleaning, less than 3% of the Dryacide carried over into the flour. Commercial cleaning of wheat removed (�s.e.) about 98 � 1% of Dryacide, and no Dryacide could be detected in the flour. Dryacide treatment did not affect flour quality as determined by the volume of sponge cakes and the production of carbon dioxide by fermenting dough.


2020 ◽  
Vol 10 (18) ◽  
pp. 6441
Author(s):  
Georgia V. Baliota ◽  
Christos G. Athanassiou

Laboratory bioassays were conducted to evaluate the insecticidal efficacy of a diatomaceous earth deposit from Greece, for a wide range of stored product insects. In this context, populations of five different insect species, Tribolium confusum Jacquelin DuVal, the confused flour beetle; Sitophilus oryzae (L.), the rice weevil; Rhyzopertha dominica (F.), the lesser grain borer; Oryzaephilus surinamensis (L.), the sawtoothed grain beetle; Cryptolestes ferrugineus (Stephens), the rusty grain beetle, which cover a major spectrum of insects species of stored products worldwide, were used in the bioassays. The different treatment of diatomaceous earth (DE) rocks (grinding, diatomaceous enrichment, powder granulometry) led to the creation of five types of formulations (namely DE1, DE2, DE3, DE5 and DE6) that exhibited significant fluctuations in their insecticidal efficacy when applied on wheat. In general, some of the modified formulations were found to be very effective against species such as R. dominica and T. confusum that may be difficult to control at the current labeled doses of commercial DE formulations. Overall, our data clearly indicate that this specific Greek deposit has considerable insecticidal properties, which can be further utilized in designing commercial formulations for insect control at the postharvest stages of durable agricultural commodities, provided that the deposit will be modified at specific enrichment and granulometry levels.


2017 ◽  
Vol 53 (No. 3) ◽  
pp. 169-176
Author(s):  
Aulicky Radek ◽  
Kolar Vlastimil ◽  
Plachy Jan ◽  
Stejskal Vaclav

The efficacy of a brief exposure (1, 7, and 10 days) to a nitrogen-controlled atmosphere (N-CA) for major storage<br />pests in a field validation study in the Czech Republic is reported. The main goal was to estimate how quickly the<br />mobile adult stages of six species of storage beetles (Oryzaephilus surinamensis, Cryptolestes ferrugineus, Tribolium<br />confusum, Tribolium castaneum, Sitophilus granarius, and Sitophilus oryzae) are killed after introduction of the<br />infested commodity to prevent their further spread to the surrounding storage bins. The trials were conducted in a<br />metal bin containing 25 t of seeds using the system of continual top-down nitrogen filling to replace the oxygen. The<br />composition of N-CA in the silo was measured continually. The target N-CA concentration (i.e., ≤ 1% O<sub>2</sub> and 99% N<sub>2</sub>)<br />was reached at the bottom of the silo after 12 h of the purging phase of nitrogen silo filling. A one-day exposure to<br />N-CA corresponds to top-down filling, which initially gives higher concentrations of N2 in the upper than in the lower<br />part of the silo: low efficacy was reached at the silo bottom (0–33.3%), while higher efficacy (16.7–100%) was reached<br />at the top of the silo bin. The mortality variation at both locations was species dependent: the most sensitive was O.<br />surinamensis, and the least sensitive were S. granarius and S. oryzae. Seven days of N-CA exposure led to 100% mortality<br />of all tested species except for S. granarius (96.7% mortality at the bottom), while 10 days of N-CA exposure led<br />to 100% mortality of all adults located at both the bottom and the top of the silo. This experiment showed that one<br />day of exposure to N-CA caused significant mortality to reduce the spread of insects from the top of the silo but not<br />from the silo bottom, and 10 days of exposure completely prevent the adult mobile pest stages of all tested species<br />from spreading from the treated silo and causing cross-infestation in the storage facility.


1993 ◽  
Vol 86 (6) ◽  
pp. 1846-1851 ◽  
Author(s):  
N. D. G. White ◽  
R. N. Sinha ◽  
D. S. Jayas ◽  
W. E. Muir

2015 ◽  
Author(s):  
Tiyyabah Khan ◽  
Ahmad Ali Shahid ◽  
Hafiz Azhar Ali Khan

Insect pests in stored wheat cause significant losses and play an important role in the dispersal of viable fungal spores of various species including aflatoxin producing Aspergillus spp. The problems of insecticide resistance in stored insects and environmental hazards associated with fumigants and conventional grain protectants underscore the need to explore reduced risk insecticides to control stored insects and the ultimate effect on fungal infection inhibition. The purpose of this study was to investigate the insecticidal potential of four biorational insecticides: spinosad, thiamethoxam, imidacloprid and indoxacarb on wheat against Rhyzopertha dominica and Sitophilus oryzae and the subsequent effect of insects’ mortality on Aspergillus flavus and A. parasiticus infection in grains. Spinosad and thiamethoxam were the most effective insecticides against R. dominica compared to S. oryzae followed by imidacloprid. Spinosad applied at 0.25, 0.5 and 1ppm and thiamethoxam at 2 and 4ppm concentrations resulted in complete mortality of R. dominica and >90% infection inhibition of A. flavus and A. parasiticus. However, indoxacarb was more toxic against S. oryzae compared to R. dominica. The mortality of R. dominica was directly related to the percent infection inhibition of A. flavus and A. parasiticus in all the treatments. Whereas, mortality of S. oryzae was only related to the percent infection inhibition of A. parasiticus in all the treatments. The results show that although both spinosad and thiamethoxam can provide protection against R. dominica and fungal infections in stored grains, more potent reduced risk insecticides and/or their combinations would be needed than either of these to provide broad spectrum protection of stored grains. In conclusion, the results of the present study provide baseline data for the management of aflatoxigenic fungi by controlling stored insects using biorational insecticides .


2017 ◽  
Vol 11 ◽  
pp. 17 ◽  
Author(s):  
ΤΗ. Buchelos ◽  
C. G. Athanassiou

Thirty Coleoptera taxa belonging to 14 families were found during samplings conducted in 4 different storage facilities at Farsala district, Central Greece, from January 1991 to February 1992. Among the most frequently found, Sitophilus oryzae, S. granarius and Rhysopertha dominica were more numerous on grain, Tribolium confusum, T castaneum and Cryptolestes ferrugineus on flour, while Oryzaephilus surinamensis and O. inercator showed no significant preference to any commodity. An analysis of the results was performed, based on the dominance and frequency criteria. The population fluctuation of the 8 most significant species is given in graphs.


2008 ◽  
Vol 38 (8) ◽  
pp. 2103-2108 ◽  
Author(s):  
Airton Rodrigues Pinto Júnior ◽  
Flavio Antonio Lazzari ◽  
Sonia Maria Noemberg Lazzari ◽  
Fabiane Cristina Ceruti

Formulações de terra de diatomácea de diferentes origens apresentam variação em toxicidade e em características físicas que afetam sua eficácia. Da mesma forma, diferentes espécies de insetos variam quanto a sua suscetibilidade ao produto. Adultos de Sitophilus oryzae (L.), Cryptolestes ferrugineus (Stephens) e Oryzaephilus surinamensis (L.) foram expostos a concentrações de 250, 500, 750, 1000 e 1250g t-1 de uma formulação de terra de diatomácea de origem brasileira (Keepdry®), em trigo armazenado, por diferentes períodos de exposição. Os grãos tratados com as diferentes concentrações foram colocados em frascos, com quatro repetições de 100g de grãos por tratamento, e infestados com os insetos. Os frascos foram mantidos em câmara climatizada a 25°C e 65% UR, avaliando-se a mortalidade periodicamente. O número de insetos mortos por parcela foi submetido à análise de variância e as diferenças entre as médias discriminadas pelo teste de Tukey a 5%. A mortalidade das três espécies foi diretamente relacionada à concentração e ao tempo de exposição, sendo que os melhores resultados foram obtidos com concentrações acima de 500g t-1. A espécie S. oryzae atingiu 100% de mortalidade somente no 14° dia de exposição, na concentração de 750g t-1. C. ferrugineus foi a espécie mais suscetível ao tratamento com a terra de diatomácea, com 100% de mortalidade a 500g t-1 já no 4° dia. Conclui-se que a terra de diatomácea utilizada apresenta um nível de controle satisfatório, e pode ser utilizada em programas de manejo de insetos, em trigo armazenado.


Author(s):  
Subash Singh ◽  
D.K. Sharma

Background: A number of storage pests viz., Rhyzopertha dominica (F.), rice weevil, Sitophilus oryzae (L.), granary weevil, Sitophilus granarius (L.) and Khapra beetle, Trogoderma granarium (Evert.) damage stored wheat. However, S. oryzae is considered a primary pest of stored wheat and has been reported to prefer soft textured wheat cultivars.Methods: The grains of three bread (soft textured) viz., HD2967, PDW314, PBW658 and three durum wheat (hard textured) cultivars viz., WHD943, PBW621, PDW291 were screened for feeding response by rice weevil, Sitophilus oryzae L. in the laboratory. Each cultivar seed was properly cleaned and disinfested before its use. A 100g seed sample of each cultivar was taken into the plastic jars. Of the pure culture, ten 1-2 week young one insects (1:1 sex ratio) were released into the jars each containing different cultivar grains. The jars were covered with white muslin as three separate storage sets, i.e., 30, 60 and 90 days after storage to record data observations. Result: Durum wheat cultivars being low in protein contents were comparatively less preferred for pest feeding and cultivar PDW291 was found highly resistant based on low insect emergence, grain damage and weight loss. The bread wheat cultivars due to high protein contents were highly preferred by the pest and cultivar HD2967 showed maximum preference. The biochemical properties like ash contents and crude fibres showed positive while crude fats and protein a negative correlation with the pest infestation. 


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