scholarly journals Management of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) using Nigerian Raw Diatomite

2020 ◽  
Vol 24 (9) ◽  
pp. 1663-1669
Author(s):  
M.A. Medugu ◽  
E. Okrikata ◽  
D.M. Dunuwel

Maize weevil, Sitophilus zeamais, whose management has largely been via traditional control practices, is a key pest of stored maize grains causing severe losses. This study explored the use of Nigerian Raw Diatomite (RD) in the management of the weevil. A 3-replicated split plot designed laboratory experiment was conducted for 6 months duration. The treatments were Raw Diatomite (RD) at the rate of 250, 500, 750 and 1000 mg/kg and a control (untreated) across four improved maize grain varieties. Data collected were on mortality, F1 progeny produced, grain weight damage, and loss. Data were analyzed with variance analysis and significantly different means were separated using Turkey Kramer HSD test at P<0.05. Results showed that the control had the least weevil mortality across the varieties throughout the periods of assessment. Highest weevil mortality was recorded with increase in dose rates of RD and progresses to 100% - largely at the 14th day post-treatment. Control recorded the highest weight loss and grain damage of 16.5% and 38.1%, respectively when compared to all the other treatment rates on the most tolerant variety (SAMMAZ 25). The study revealed that RD had a promising potential to substitute synthetic insecticides and can be incorporated into the integrated pest management strategy against maize weevil. We therefore suggest that further work be done to refine the Nigerian RD so as to standardize the most effective dosage application rate for management of insect pests of stored maize and other cereals. Keywords: Raw Diatomite, Sitophilus zeamais, Maize grain damage

Author(s):  
Kimondo Mutambuki ◽  
Paddy Likhayo

Abstract The performance of six grain storage technologies for the control of insect pests in maize was evaluated over a 36-week (9-month) storage period. The six technologies used were: two ZeroFly® hermetic bag brands (laminated and non-laminated); Purdue Improved Crop Storage (PICS) bag; non-hermetic ZeroFly® bag; woven polypropylene (PP) bag containing maize grain treated with Actellic Gold® Dust (pirimiphos-methyl 1.6% + thiamethoxam 0.3%) and woven PP bag containing untreated grain. Each bag was filled with 50 kg maize grain and four replicates of each were set up. With the exception of the non-hermetic ZeroFly® bag, 50 live adults of the larger grain borer Prostephanus truncatus and of the maize weevil Sitophilus zeamais, were introduced into all the bags. Insects were not introduced into the non-hermetic ZeroFly® bag to assess its effectiveness in repelling infestation from outside. Parameters recorded were gas composition (oxygen and carbon dioxide) levels inside the bags; weight of flour generated by insect feeding activities; grain moisture level; live adult insect counts; grain damage and weight loss; grain germination rate and aflatoxin level. At termination, the plastic liners of the hermetic bags were examined for perforations. Results show that oxygen depletion and carbon dioxide evolution were faster in ZeroFly® hermetic compared to PICS bags. Throughout the 36-week storage trial, grain damage remained below 4% and weight loss below 3% in all the treatments except in the untreated PP bags in which it increased to 81.1 and 25.5%, respectively. The hermetic PICS, ZeroFly® and Actellic Gold dust-treated PP bags maintained grain germination at 60%, which was lower than the initial 90%, while in untreated control, it reduced to 4.7%. The mean aflatoxin levels fluctuated between 0.39 and 3.56 parts per billion (ppb) during 24 weeks of storage in all the technologies tested, which is below the acceptable maximum level of 10 ppb in maize. Based on the evaluation results, it can be concluded that hermetic PICS and ZeroFly® bags and woven PP bag with Actellic Gold dust-treated grain effectively protected stored maize grain from insect attack and weight losses. Appropriate strategies and mechanisms for the effective and efficient adoption of hermetic storage bag technology at scale would contribute towards global food security.


Insects ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 204 ◽  
Author(s):  
Kimondo Mutambuki ◽  
Hippolyte Affognon ◽  
Paddy Likhayo ◽  
Dieudonne Baributsa

Hermetic technologies are being promoted in Africa as safer and more effective methods of grain storage on smallholder farms. However, farmers and policy makers lack knowledge of their efficacy in controlling major stored grain pests. An on-station study was conducted to evaluate the triple layer Purdue Improved Crop Storage (PICS) airtight bags against two major storage insect pests. Two sets each of PICS, jute and polypropylene bags were filled with 50 kg maize grain per bag. Each set was replicated four times. One set of PICS bags was each infested with 50 insects each of the larger grain borer P. truncatus and the maize weevil S. zeamais; while the other set was not. One set of jute and polypropylene woven bags was treated with a cocktail of 1.6% Pirimiphos methyl and 0.3% Permethrin, serving as positive controls; while the remaining sets with untreated maize grain formed negative controls. Gas analysis in the PICS bags followed the expected trend with oxygen levels falling sharply below 10% and carbon dioxide increasing to almost 10% after 12 weeks hence resulting in insect death. After 16 weeks, increase in oxygen levels may be attributed to perforation of the bags from outside by the P. truncatus. Results showed that PICS bags were significantly (P < 0.05) superior to treated and untreated controls of polypropylene and jute bags in suppressing insect development, maize grain damage and weight loss during storage. Weight loss in polypropylene and jute bags reached 40% and 41%, respectively, at 24 weeks after storage compared to PICS (2.4–2.9%). These results demonstrate that PICS bags can be used to store maize against P. truncatus and S. zeamais attack.


2020 ◽  
Vol 42 (2) ◽  
Author(s):  
Nguyen Van Dzuong ◽  
Khuat Dang Long

The instintive behaviour exhibited by insects in the selecting  food is always a matter of  interests to entomologists, and it is one of the fundamental principles underlining the application of entomology to agriculture, horticulture and forestry. Food seclection is an important characteristic of insects that help them survive in periods with insufficient foods.Three grain types of food, maize grain, long-grain rice and soybean grain, were used in this sudy for detecting food selection behaviours of maize weevil, Sitophilus zeamais. Grains were kept in box traps put in the different stores in Son La during 90 days. The result showed that maize weevil, Sitophilus zeamais, prefered traps with maize grains (71.4%) considerably more than ones with long-grain rice (14.3%) and soybean grain (14.3%). Meanwhile, the cornsap beetle, Carpophilus dimidiatus, was mostly observed in maize grain (98.5%) and to a lesser degree, in soybean grain (1.5%); and the dried-fruit beetle, Carpophilus hemipterus, was abundantly observed in maize grain (93.1%) and less in soybean grain (6.9%). The red flour, Tribolium castaneum, also tended to select all the three food grain, i.e. maize grain: 53.5%, long-rice grain: 35.2%, and soybean grain: 11.3%.Comparing f beetle individuals captured on three types of food grains showed that the maize weevil, Sitophilus zeamais, is the most abundant species. The percentage this store beetle among all beetles observed in maize, soybean grains and long-rice grains were 57.0%, 84.9% and 27.6%, respectively. Interestingly, Ahasverus advena, foreign grain beetle, occurred abundantly on long-rice gain (61.7%), i.e. this grain is a suitable food for the development of this beetle. 


2009 ◽  
Vol 99 (4) ◽  
pp. 393-400 ◽  
Author(s):  
N.M.P. Guedes ◽  
R.N.C. Guedes ◽  
G.H. Ferreira ◽  
L.B. Silva

AbstractInsects have evolved a variety of physiological and behavioral responses to various toxins in natural and managed ecosystems. However, insect behavior is seldom considered in insecticide studies although insects are capable of changing their behavior in response to their sensory perception of insecticides, which may compromise insecticide efficacy. This is particularly serious for insect pests that are physiologically resistant to insecticides since insecticide avoidance may further compromise their management. Locomotion plays a major role determining insecticide exposure and was, therefore, considered in investigating the behavioral responses of male and female adult insects from an insecticide-susceptible and two insecticide-resistant strains of the maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), a major pest of stored cereals. Different dose-dependent behavioral responses were expected among strains with behavioral resistance less likely to occur in physiologically resistant insects since they are able to withstand higher doses of insecticide. The behavioral responses to deltamethrin-sprayed surfaces differed among the maize weevil strains. Such responses were concentration-independent for all of the strains. Stimulus-independent behavioral resistance was unrelated to physiological resistance with one resistant strain exhibiting higher rates of flight take-off and the other resistant strain exhibiting lower flight take-off. Female mobility was similar for all strains, unlike male mobility. Males of each strain exhibited a pattern of mobility following the same trend of flight take-off. Behavioral patterns of response to insecticide are, therefore, variable among strains, particularly among insecticide-resistant strains, and worth considering in resistance surveys and management programs.


2015 ◽  
Vol 35 (04) ◽  
pp. 185-192 ◽  
Author(s):  
L.C. Nwosu ◽  
C.O. Adedire ◽  
E.O. Ogunwolu ◽  
M.O. Ashamo

Susceptibility studies keep farmers informed, and enhance breeding programmes' testing against infestation and damage by stored product pests. Therefore, the susceptibility of 20 elite maize varieties toSitophilus zeamaisinfestation was investigated in the laboratory at 32.7 °C ambient temperature and 70.4% relative humidity. The varieties tested were obtained from the Maize Breeding Units of International Institute of Tropical Agriculture (IITA), and Institute of Agricultural Research and Training (IAR&amp;T), both in Ibadan, Nigeria. Susceptibility was assessed, using as indices, weevil mortality and survival rates, percentage grain damage, percentage grain weight loss, weight of grain powder, weevil development time, and number of emerged adults. The susceptibility index was determined post-infestation at 56 days using Dobie's formula and at 90 days from a new formula derived from Dobie's formula. Susceptible varieties produced significantly (P≤ 0.05) high numbers of F1and F2progeny, and had significantly (P≤ 0.05) low weevil mortality and early first weevil emergence. Grain damage and loss increased with storage duration. There was no visible damage to varieties 2000SYNEE-WSTR and TZBRELD3C5 at 56 days post-infestation. At 90 days, the two varieties had the lowest percentage grain damage, percentage weight loss, and weight of grain powder. The index of susceptibility at F2progeny showed that the resistant varieties decreased in number from 17 (85%) to 13 (65%) and the moderately resistant varieties increased from 2 (10%) to 6 (30%). This suggests the effect of prolonged storage duration on the inherent ability of varieties to resist weevil attack. Variety PVASYN3F2 was susceptible. The factors conferring high resistance to 2000SYNEE-WSTR and TZBRELD3C5 should be investigated. They should be promoted to controlS. zeamaisinfestation and damage in stored maize.


2013 ◽  
Vol 36 (3-S3-A) ◽  
pp. 347
Author(s):  
Silverio García-Lara ◽  
David J. Bergvinson

The maize weevil (MW) (Sitophilus zeamais), and the larger grain borer (LGB) (Prostephanus truncatus) are major storage pests causing serious losses in maize (Zea mays L.) in developing countries of Latin America (LA). This study identified maize landraces with high levels of resistance to MW and LGB by screening 1171 genotypes collected from 24 LA countries in 38 sampling areas. Maize grain weight losses (GWL), total dust production (TDP) and number of adult progeny (NAP) were measured for LGB and MW attack in each genotype. Susceptibility traits to MW and LGB were related to specific geographical location. Range of resistance for MW was from 0.6 to 51 %, while for LGB from 0.1 to 66 %. Approximately 28 % of the analyzed genotypes showed high level of resistance to MW, with Antilles region offering the most resistant accessions with races of EarCar, Chande, Haitye, Nal-Tel, Tuson, and Canill. Resistance to LGB was observed in 22 % of genotypes analyzed with accessions from Southern México with races of Cónico, Nal-Tel, Vandeño, Elotes Occidentales, Cubano, Tuxpeño, and Tepecintle. Low correlation (r = 0.28; P < 0.01) between maize resistance to MW and LGB indicated a divergent adaptive response of maize grain to these two pest. Geographic data showed a negative correlation between latitude and longitude with MW resistance traits being significant only for longitude (r = -0.253; P < 0.05). Opposite trend of correlations, positive but not significant, was observed for LGB resistance traits. These results indicate an influence of geographic location in local varieties being selected for storage pest resistance over time. Genotypes with excellent postharvest insect resistance have now been identified for maize breeders to use in developing improved cultivars for use in LA.The maize weevil (MW) (Sitophilus zeamais), and the larger grain borer (LGB) (Prostephanus truncatus) are major storage pests causing serious losses in maize (Zea mays L.) in developing countries of Latin America (LA). This study identified maize landraces with high levels of resistance to MW and LGB by screening 1171 genotypes collected from 24 LA countries in 38 sampling areas. Maize grain weight losses (GWL), total dust production (TDP) and number of adult progeny (NAP) were measured for LGB and MW attack in each genotype. Susceptibility traits to MW and LGB were related to specific geographical location. Range of resistance for MW was from 0.6 to 51 %, while for LGB from 0.1 to 66 %. Approximately 28 % of the analyzed genotypes showed high level of resistance to MW, with Antilles region offering the most resistant accessions with races of EarCar, Chande, Haitye, Nal-Tel, Tuson, and Canill. Resistance to LGB was observed in 22 % of genotypes analyzed with accessions from Southern México with races of Cónico, Nal-Tel, Vandeño, Elotes Occidentales, Cubano, Tuxpeño, and Tepecintle. Low correlation (r = 0.28; P < 0.01) between maize resistance to MW and LGB indicated a divergent adaptive response of maize grain to these two pest. Geographic data showed a negative correlation between latitude and longitude with MW resistance traits being significant only for longitude (r = -0.253; P < 0.05). Opposite trend of correlations, positive but not significant, was observed for LGB resistance traits. These results indicate an influence of geographic location in local varieties being selected for storage pest resistance over time. Genotypes with excellent postharvest insect resistance have now been identified for maize breeders to use in developing improved cultivars for use in LA.


Author(s):  
Julián Hernández-Cruz ◽  
Alfonso Luna-Cruz ◽  
Esperanza Loera-Alvarado ◽  
Evert Villanueva-Sánchez ◽  
Nadia Landero-Valenzuela ◽  
...  

Abstract The insecticidal and repellent effect of essential oil isolated from fresh leaves of Porophyllum linaria on maize weevil was evaluated, as well as the effect on the grain germination after treated. In total, 28 constituents were identified by gas chromatography coupled with mass spectrometry accounting for 99.86% of whole essential oil. The main majority compounds were β-myrcene (41.94%), D-limonene (20.29%), and estragole (20.03%). Contact toxicity significantly increased with dose and time after treatment. With the 800 ppm (highest concentration), the mortality (%) obtained for the tenth and fifteenth day was 43 and 82%, respectively, whereas with 50 ppm (lowest concentration) 30% mortality was obtained at the end of the experiment (fifteenth day). At 15 d (end of the experiment), the LC50 y LC90 were obtained with values of 329.01 ± 44.35 y 1058.86 ± 117.76 ppm, respectively. For a concentration of 800 ppm, a selection index of zero was obtained, indicating the preference of the pest to the untreated maize (control). The maize grains germination test showed a significant reduction both in the length of hypocotyl and radicle of maize grain. So, in the highest dose, the hypocotyl and radicle length was 1.40 ± 0.34 and 9.14 ± 0.55 cm, respectively, whereas the control group registered 3.28 ± 0.39 and 13.02 ± 0.97 cm, respectively. This finding is promising since as it could result in the identification of botanical substances capable of suppressing maize weevil, Sitophilus zeamais development.


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