Effect of Two Azadirachtin Formulations against Adults of Sitophilus oryzae and Tribolium confusum on Different Grain Commodities

2007 ◽  
Vol 70 (7) ◽  
pp. 1627-1632 ◽  
Author(s):  
NICKOLAS G. KAVALLIERATOS ◽  
CHRISTOS G. ATHANASSIOU ◽  
CONSTANTIN J. SAITANIS ◽  
DEMETRIUS C. KONTODIMAS ◽  
ALEXANDER N. ROUSSOS ◽  
...  

The insecticidal effect of two azadirachtin-based insecticides, NeemAzal-T/S and Oikos 32 EC, was examined against adults of the grain beetles Sitophilus oryzae and Tribolium confusum on wheat and maize under different temperature and humidity regimes. The insecticides were applied at three dosages, equivalent to 50, 100, and 200 mg of active ingredient per kg of grain. Adults of the above species were exposed to the treated grains at 20, 25, and 30°C and two relative humidity levels (55 and 75%), and mortality was assessed after 14 days of exposure. All adults were then removed, and the treated substrate remained under the same conditions for 45 more days. After this period, the grains were checked for progeny production. In both species and both commodities, mortality increased with insecticide dosage. For many dosage-formulation combinations, mortality increased with temperature at 55% relative humidity but the reverse was observed at 75% relative humidity. Comparing the two formulations, NeemAzal-T/S was more effective than Oikos 32 EC at all the combinations tested. NeemAzal-T/S was more effective at high relative humidity, but the efficacy of Oikos 32 EC was not much affected by the relative humidity. Survival was high, even at the higher dosages, in some of the temperature-humidity combinations. Progeny production of S. oryzae in the treated grains was considerably higher than that of T. confusum. The results of the present study indicate that further dosage increases and longer exposure times are needed to obtain a complete (100%) adult mortality in all combinations tested. However, the feasibility of using higher azadirachtin dosages (>200 mg/kg grain) is questionable for cost reasons. Consequently, the use of these substances is not comparable to the use of traditional grain protectants, which are usually used at dosages of <5 mg/kg grain. Although azadirachtin-based insecticides can be used with success for protection of stored grain, our study demonstrated that under certain circumstances such an application may not be effective. Abiotic factors (formulation, temperature, and relative humidity) had a more serious impact on the efficacy of these insecticides than did biotic factors (target species and commodity).

2021 ◽  
Vol 45 ◽  
Author(s):  
Cennet Yaman ◽  
Şeyda Şimşek

ABSTRACT The search for new plant natural products with insecticidal properties to control insect pests in agriculture has gained relevance in the past decades. The aim of the study was to investigate the insecticidal activity of extracts derived from flower, leaf, and stem of three Hypericum species (Hypericum heterophyllum, Hypericum perforatum, Hypericum scabrum) against the adults of three important stored grain insect pests namely; Sitophilus oryzae (Curculionidae), Rhyzopertha dominica (Bostrichidae) and Tribolium confusum (Tenebrionidae). The insects were incubated with the food under 10% concentration of Hypericum extracts and the mortality was recorded after 24, 48 and 72 h of exposure. The extracts of the Hypericum species and exposure time were found to have statistically significant effective against the three insect pests. After 72 h exposure, the mortality ranged from 4.3 to 94.1 % for all insects. Among tested insects, R. dominica was more susceptible than T. confusum and S. oryzae. Although desirable insecticidal effect against the insects were recorded from all the three Hypericum species, the leaf extract of H. perforatum was more effective on R. dominica, while the flower and stem of H. scabrum displayed high toxic effect on T. confusum and S. oryzae, respectively. The leaf extracts, of H. perforatum, in particular, may be used as source of new potential botanical insecticides against R. dominica in stored grains.


2017 ◽  
Vol 37 (04) ◽  
pp. 243-258 ◽  
Author(s):  
Charles Adarkwah ◽  
Daniel Obeng-Ofori ◽  
Vanessa Hörmann ◽  
Christian Ulrichs ◽  
Matthias Schöller

Abstract Food losses caused by insects during postharvest storage are of paramount economic importance worldwide, especially in Africa. Laboratory bioassays were conducted in stored grains to determine the toxicity of powders of Eugenia aromatica and Moringa oleifera alone or combined with enhanced diatomaceous earth (Probe-A® DE, 89.0% SiO2 and 5% silica aerogel) to adult Sitophilus granarius, Tribolium castaneum and Acanthoscelides obtectus. Adult mortality was observed up to 7 days, while progeny production was recorded at 6–10 weeks. LD50 and LT50 values for adult test insects exposed to plant powders and DE, showed that A. obtectus was the most susceptible towards the botanicals (LD50 0.179% and 0.088% wt/wt for E. aromatica and M. oleifera, respectively), followed by S. granarius. Tribolium castaneum was most tolerant (LD50 1.42% wt/wt and 1.40% wt/wt for E. aromatica and M. oleifera, respectively). The combined mixture of plant powders and DE controlled the beetles faster compared to the plant powders alone. LT50 ranged from 55.7 h to 62.5 h for T. castaneum exposed to 1.0% M. oleifera and 1.0% DE, and 0.5% E. aromatica and 1.0% DE, respectively. Botanicals caused significant reduction of F1 adults compared to the control. Combined action of botanical insecticides with DE as a grain protectant in an integrated pest management approach is discussed.


2016 ◽  
Vol 106 (4) ◽  
pp. 446-456 ◽  
Author(s):  
M.C. Boukouvala ◽  
N.G. Kavallieratos ◽  
C.G. Athanassiou ◽  
L.P. Hadjiarapoglou

AbstractMembers of the pyrrole group are likely to have interesting properties that merit additional investigation as insecticides at the post-harvest stages of agricultural commodities. In the present work, the insecticidal effect of two new pyrrole derivatives, ethyl 3-(benzylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-carboxylate (3i) and isopropyl 3-(benzylthio)-4,6-dioxo-5-phenyl-2,4,5,6-tetrahydropyrrolo[3,4-c]pyrrole-carboxylate (3k) were studied as stored-wheat protectants against two major stored-product insect species, the confused flour beetle, Tribolium confusum Jaquelin du Val adults and larvae and the Mediterranean flour moth, Ephestia kuehniella Zeller larvae at different doses (0.1, 1 and 10 ppm), exposure intervals (7, 14 and 21 days), temperatures (20, 25 and 30°C) and relative humidity (55 and 75%) levels. For T. confusum adults, in the case of the pyrrole derivative 3i, mortality was low and it did not exceed 32.2% in wheat treated with 10 ppm 3i at 30°C and 55% relative humidity. Progeny production was very low (<1 individual/vial) in all combinations of 55% relative humidity, including control. In the case of the pyrrole derivative 3k, mortality reached 67.8% at 30°C and 55% relative humidity in wheat treated with 10 ppm after 21 days of exposure. Progeny production was low in all tested combinations (≤0.7 individuals/vial) of 55% relative humidity, including control. For T. confusum larvae, in the case of the pyrrole derivative 3i, at the highest dose, mortality was 82.2% at 25°C and 55% relative humidity whereas in the case of 3k it reached 77.8% at the same combination. In contrast, mortality at 75% relative humidity remained very low and did not exceed 13.3%. For E. kuehniella larvae, the highest mortalities, 44.4 and 63.3%, were observed in 10 ppm at 25°C and 55% relative humidity for both pyrrole derivatives. The compounds tested here have a certain insecticidal effect, but this effect is moderated by the exposure, the target species, the temperature and the relative humidity.


1980 ◽  
Vol 20 (103) ◽  
pp. 234 ◽  
Author(s):  
ER Sinclair ◽  
M Bengston

In a survey of 60 grain farms on the Darling Downs, Queensland, during 1977-78, the flat grain beetles Cryptolestes spp., which are germ feeders in stored grains, were found on 39 of the farms and in 15% of the 483 samples taken. Ninety percent of infestations involving Cryptolestes spp. were found in bag or bulk stores of seed and feed grain, where they were usually associated with heavy infestations of the three more common stored grain pests, the rice weevil Sitophilus oryzae (L.), the lesser grain borer Rhyzopertha dominica (F.), and the red flour beetle Tribolium castaneum (Herbest.). Three species of Cryptolestes were detected: C. pusillus (Schonherr) (45.6% of farms surveyed), C. ferrugineus (Steph.) (28.1 %), and C. pusilloides (Steel and Howe) (15.8%). During the farm survey, samples were also collected from 8 of the 11 central storages reported infested with Cryptolestes spp. C. ferrugineus was present in each of these samples, C. pusillus in only one, whilst C. pusilloides was not found. The three species were tested for resistance to malathion and fenitrothion, the most commonly used grain-protectant chemicals, by exposing adults to treated wheat. C. pusillus and C. pusilloides were susceptible to both malathion and fenitrothion (LC99.9 < 1 mg kg-1). C. ferrugineus, whilst susceptible to fenitrothion (LC99.9 < 1 mg kg-1) was resistant to malathion, with LC99.9 of 300-400 mg kg-1 compared with the recommended dose of 18 mg kg -1. Although C. pusillus was the most common species on farms, it was concluded that C. ferrugineus was the most important overall because it is biologically better suited to the grain in central storages, which is typically hot (>30�C) and of low moisture content (< 12% for wheat).


1984 ◽  
Vol 24 (125) ◽  
pp. 260 ◽  
Author(s):  
ER Sinclair ◽  
J Alder

One hundred unsexed adults of each of the following coleopterous species were added to 27 .3 kg of clean wheat: Sitophilus oryzae (L.) (rice weevil), Rhyzopertha dominica (F.) (lesser grain borer), Tribolium castaneum (Herbst) (rust-red flour beetle), and the flat grain beetles Cryptolestes pusillus (Schonherr), C. ferrugineus (Stephens), and C. pusilloides (Steele and Howe). For 15 months, measurements were made of population size and emigration from this wheat bulk. The highest populations recorded for each species were: 138 850, 65 680, 9 060, 47 000, 15 530, 11 940, respectively, and total emigrant numbers during the period were: 774 682, 278 094, 123 784, 335 588, 39 070, 9 352, respectively. Such high numbers of emigrants in relation to relatively low source populations emphasize the significance of small amounts of infested grain as sources of infestation of large grain bulks, and hence the importance of grain hygiene. The proportion of females in the populations of four species changed significantly from 0.50 as populations developed. Emigration behaviour was influenced most commonly by temperature, insect numbers, and wheat age, but these factors did not act uniformly on all species. Negligible numbers of emigrants returned to the food source. Low numbers caught in food traps away from the source were consistent with these not being attractive but traps near the shed walls caught greater numbers than expected.


2012 ◽  
Vol 44 (3) ◽  
pp. 11 ◽  
Author(s):  
Yacoub A. Batta

This study aimed to evaluate the entomopathogenic activity of <em>Fusarium avenaceum</em> (strain 10A) against adults of <em>Sitophilus oryzae </em>infesting wheat grain. Bioassays were carried out to determine the adult mortality of<em> S. oryzae</em> when the conidial suspension of the fungus strain was applied using three types of fungus treatment. Results obtained have indicated significant differences (P=0.05) in the mean percentage of adult mortality due to the treatment with the fungus compared to the control. The highest mean percentage of adult mortality was obtained by the direct spraying of <em>S. oryzae</em> adults with the fungus conidial suspension before introduction of the treated adults into pots containing wheat grain; the lowest mean percentage of adult mortality was obtained by spraying the inner surfaces of pots with the fungus conidial suspension before introducing the grain and insects. This study demonstrated the typical growth of <em>F. avenaceum</em> on the outer surfaces of the dead treated adults of <em>S. oryzae</em>. Presence of the external fungus growth on the dead insects indicated that the death of <em>S. oryzae</em> adults was attributed to the fungus infection. Results obtained in the present paper represent the first record of efficacy of <em>F. avenaceum</em> against a coleopteran stored-grain insect, mainly including <em>S. oryzae</em>.


Agronomy ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 156
Author(s):  
Georgia V. Baliota ◽  
Evagelia Lampiri ◽  
Christos G. Athanassiou

This study evaluated the influence of temperature and relative humidity (RH) on the insecticidal effect of diatomaceous earth (DE) at two concentrations, 500 and 1000 ppm, on wheat, for the control of Cryptolestes ferrugineus (Stephens) (Coleoptera: Cucujidae), Oryzaephilus surinamensis (L.) (Coleoptera: Silvanidae), and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae). These bioassays were carried out in all combinations of four temperature levels (15, 20, 25, and 30 °C), and two relative humidity levels (55 and 75%). Cryptolestes ferrugineus and O. surinamensis were found to be much more susceptible to the DE-treated wheat than T. confusum, but the increase of the DE dose increased the mortality level for all three species. Although the increase of temperature and the decrease of RH increased insect mortality in some of the combinations tested, the reverse was observed in some treatments, suggesting that there are considerable differential effects of these factors in DE efficacy. The increase of insect exposure from 1 to 21 days notably increased insect mortality, suggesting that exposure is a critical factor that may alleviate possible differential effects of certain abiotic conditions. The results of the present work provide data that illustrate the viability of the utilization of DE in stored product protection, as alternatives to chemical control methods.


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