Susceptibility of Ethiopian wheat varieties to granary weevil and rice weevil infestation at optimal and sub-optimal temperatures

2019 ◽  
Vol 83 ◽  
pp. 267-274
Author(s):  
Karta Kaske Kalsa ◽  
Bhadriraju Subramanyam ◽  
Girma Demissie ◽  
Rizana Mahroof ◽  
Admasu Worku ◽  
...  
1984 ◽  
Vol 67 (3) ◽  
pp. 644-647
Author(s):  
Randy L Wehling ◽  
David L Wetzel ◽  
John R Pedersen

Abstract Liquid chromatography is used to measure the uric acid content of wheat internally infested by various growth stages of granary weevil (Sitophilus granarius), rice weevil (Sitophilus oryzae), and lesser grain borer (Ryzopertha dominica). Good correlation exists between numbers of insects and uric acid content of grain infested by a given stage of an internally infesting stored product insect, with correlation coefficients ranging from 0.970 to 0.998. Uric acid content of infested grain increases as the insect life cycle progresses, with granary weevil producing the greatest quantities of uric acid followed in order by rice weevil and lesser grain borer. A detection limit for the analytical procedure of less than 1.0 ppm uric acid allows detection of infestation levels as low as one kernel per 100 g grain for late instar granary weevil larvae. This limit is sufficiently sensitive to detect levels of infestation that may be commonly encountered in commerce.


1905 ◽  
Vol 37 (7) ◽  
pp. 233-235
Author(s):  
Arthur Gibson

Every year, in the United States and Canada, Thoudands of dollars worth of stored grain is ruined by granary insects, chiefly of three species. These are all well known, and much has been written concerning their habits and the methods by which they can be destroyed. Besides the three very injurious species, the Granary Weevil, the Rice Weevil and the Angoumois Grain Moth, which are responsible for the most of the damage done, there are a great many other kinds of insects which do serious harm to stored grain and various other edible products.


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. 


1997 ◽  
Vol 80 (5) ◽  
pp. 997-1005 ◽  
Author(s):  
Ahmad R Ghaedian ◽  
Randy L Wehling

Abstract Sound and infested wheat kernels containing lateinstar granary weevil larvae, as identified by X-ray analysis, were used to evaluate the ability of nearinfrared (NIR) spectroscopy to predict the presence of insect larvae in individual wheat kernels. Diffuse reflectance spectra at 1100-2500 nm were recorded from individual infested and sound kernels. Principal component analysis (PCA) of NIR spectra from sound kernels was used to construct calibration models by calculation of Mahalanobis distances. Calibration models were then applied to spectra obtainedfrom both sound and infested kernels in a separate validation set. A 5-factor PCA model using data from a first-derivative spectral transformation was the best model for correctly classifying kernels in an expanded validation sample set, including 100% of sound, 93% of infested, 95% of sound air dried, 86% of infested air dried kernels, and 90% of sound kernels from 6 wheat varieties. Calibrations using the spectral region from 1100 to 1900 nm were least sensitive to kernel moisture differences. Similar results were obtained when discriminant analysis was applied to log 1/R data from selected discrete wavelengths of NIR spectra.


Author(s):  
Adrian DINUŢĂ ◽  
Horia BUNESCU ◽  
Gabriela Teodora DAN ◽  
Ilonka BODIS

Taking into account that chemical treatments are generally pollutant, their use in crop protection is generally accepted, but at the same time is subject to narrow limitations in case of stocks used for human and animal consumption. This paper presents the results of some laboratory tests regarding the resistance of different genotypes - wheat varieties and corn hybrids on the attack of grain weevil (Sitophilus granarius L.) that would help control this pest through ecological methods. Due to the lack of information in the speciality literature worldwide regarding the resistance of stored cereal grains on the attack of grain weevil, we decided to study this aspect thoroughly between 2005-2009, in the Entomology Laboratory at Agricultural Faculty of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca.


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