scholarly journals Integration of botanicals and inert dusts with resistant varieties against Sitophilus zeamais (Motsch.) of stored maize (Zea mays) in Ethiopia

2018 ◽  
Vol 10 (2) ◽  
pp. 6-13
Author(s):  
Hiruy Berhanu ◽  
Getu Emana
2003 ◽  
Vol 27 (2) ◽  
pp. 339-347 ◽  
Author(s):  
Marcelo Coutinho Picanço ◽  
Tederson Luiz Galvan ◽  
João Carlos Cardoso Galvão ◽  
Eny do Carmo Silva ◽  
Lessando Moreira Gontijo

Conduziu-se este trabalho visando a estudar as intensidades de perdas, densidades de insetos-praga e inimigos naturais em 49 cultivares de milho (Zea mays L.) em cultivo de safrinha em Coimbra, MG, Brasil. A produtividade média das cultivares foi de 3438,74 kg/ha, sendo as cultivares Traktor, CDX98D06, CO9621, OC705 e 97TR61 as mais produtivas. Ocorreram 29,62% de perdas na produtividade das cultivares, devido principalmente ao ataque de Sitophilus zeamais (Motsch., 1865) (Coleoptera: Curculionidae) aos grãos. O inseto-praga mais abundante foi Dalbulus maidis (DeLong & Wolcott, 1923) (Homoptera: Cicadellidae), seguido por adultos de Diabrotica speciosa (Germ., 1824) (Coleoptera: Chrysomelidae) e lagartas de Spodoptera frugiperda (Smith, 1797) (Lepidoptera: Noctuidae). O inimigo natural mais abundante foi o predador Doru luteipes (Scudder, 1876) (Dermaptera: Forficulidae). As densidades desses insetos foram semelhantes nas cultivares, com exceção de D. maidis. As cultivares menos atacadas por D. maidis foram: SHS5060, COE9994, HT8A97, NB6077, Z8550, CD3351, Maister, AG122, HS12L1133, HT47C, 97TR61, CDX98D04 e A975.


Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 532
Author(s):  
William R. Patiño-Bayona ◽  
Leidy J. Nagles Galeano ◽  
Jenifer J. Bustos Cortes ◽  
Wilman A. Delgado Ávila ◽  
Eddy Herrera Daza ◽  
...  

Chemical control of the maize weevil (Sitophilus zeamais) has been ineffective and presents serious collateral damage. Among plant-derived insecticides, essential oils (EOs) are suitable candidates to control this stored products pest. In this work, the insecticidal activities of 45 natural EOs against S. zeamais adults were screened, and the most promising ones (24 EOs) were characterized by GC–MS. The repellent and toxic effects (contact and fumigant) of these 24 EOs were determined, and by a cluster analysis they were classified into two groups considering its fumigant activity and contact toxicity. For the EOs with the highest fumigant potential (14 oils) and their main active constituents (17 compounds), lethal concentrations were determined. The most active EOs were those obtained from L. stoechas and L. alba, with LC50 values of 303.4 and 254.1 µL/L air and characterized by a high content of monoterpenes. Regarding the major compounds, the oxygenated monoterpenes R-(+)-pulegone (LC50 = 0.580 mg/L air), S-(-)-pulegone (LC50 = 0.971 mg/L air) and R-(-)-carvone (LC50 = 1.423 mg/L air) were the most active, as few variations in their concentrations significantly increased insect mortality.


2019 ◽  
Vol 3 (6) ◽  
pp. 2412-2428
Author(s):  
Wagner dos Santos Machado ◽  
Aline Fonseca do Nascimento ◽  
Hebert da Cruz Damasceno ◽  
Joice dos Santos Pinheiro ◽  
Layanne Muniz Sprey

O milho (Zea mays) é um produto agrícola cultivado em todo território nacional e com inúmeras utilizações. Com o surgimento da agricultura moderna, as sementes crioulas foram, em geral, substituídas por cultivares híbridos, com elevado potencial produtivo, porém mais dependentes de insumos e tecnologias intensivas. Pode ser armazenado por longos períodos, porém, devido seu armazenamento sem inspeção inicial do local, pode propiciar o ataque de pragas, dentre elas, destaca-se o gorgulho Sitophilus zeamais que danifica o grão acarretando grandes prejuízos para os agricultores e tornando o impróprio para o consumo. Uma boa fonte de genótipos resistentes são as variedades crioulas, ou seja, aquelas tradicionalmente cultivadas pelos pequenos agricultores e que ainda não foram modificadas, seja pela biotecnologia ou por outros processos de melhoramento. O teste de germinação é realizado para determinar o percentual germinativo das sementes de milho, teste esse baseado no procedimento oficial da RAS para avaliar a capacidade das sementes desenvolverem plântulas normais em condições ideais. Sendo assim, o objetivo desse trabalho foi mostrar, através de seu material genético o potencial de 10 variedades multiplicadas em relação ao cultivar convencional SSH 7990 PRO2, assim avaliando seu poder germinativo e sua resistência ao ataque do Gorgulho (Sitophilus zeamais). Para ambos os testes o delineamento experimental utilizado foi o inteiramente casualizado. No método de confinamento ou sem chance de escolha foram utilizadas 4 repetições com 10 gramas da variedade crioula mais a testemunha, contendo em cada recipiente 30 gorgulhos não sexados. Finalizando a avaliação com teste de germinação, utilizou-se 5 repetições de 50 sementes em rolo de papel germitest, totalizando 250 sementes, onde a variedade de Milho colorido obteve um maior percentual de germinação, com média de 99,6 %. Considerando a evidência desses materiais crioulos serem mais resistentes ao ataque da praga, pode-se concluir que de fato, esses materiais são mais tolerantes comparadas a cultivar híbrida, assim as variedades Pipoca preta, Dente de cavalo e Jabotão vermelho se mostraram menos atraentes ao gorgulho, e a cultivar convencional SSH 7990 PRO2 se mostrou mais atraente, tendo uma perda média de peso de 0,3538 gramas durante os 15 dias confinados.


2017 ◽  
Vol 30 (4) ◽  
pp. 220
Author(s):  
Diligent Oboho ◽  
Joseph Eyo ◽  
Felicia Ekeh ◽  
Solomon Okweche

A laboratory experiment was conducted to evaluate the insecticidal property of <em>Cymbopogon citratus</em> leaf extract as seed protectant against maize weevil. One (1) gram each of acetone, chloroform, methanol and aqueous extracts were re-suspended in 5 ml of deionized water and used to impregnate filter papers set in four replicates. Varied concentrations of the aqueous extract per 50 g of <em>Zea mays</em> grains infested with 10 pairs of sexed <em>Sitophilus zeamais</em> for 28 days were tested for insecticidal properties and compared with experimental and synthetic conventional insecticide [Coopex (0.25 g)] controls. Parameters assessed were effect of <em>C. citratus</em> extracts on weevil mortality (toxicity test) and protection of maize against <em>S. zeamais</em>. Data obtained were analyzed using Analysis of Variance (ANOVA) and means were separated using New Duncan Multiple Range Test at 5% level of significance. Results showed significant (P &lt; 0.05) concentration and duration dependent mortalities of <em>S. zeamais</em>. The aqueous extract gave the highest protection of the maize grains followed by chloroform, methanol and acetone extracts respectively. The insecticidal potency of <em>C. citratus</em> extracts and its availability places it as an attractive biopesticide in traditional post-harvest seed protection.


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.


1987 ◽  
Vol 22 (4) ◽  
pp. 307-310 ◽  
Author(s):  
W. W. McMillian ◽  
N. W. Widstrom ◽  
D. M. Wilson

The use of plants that resist insects has been suggested as a potential means of reducing aflatoxin contamination in some crops. Dent corn, Zea mays L., germplasm possessing the characteristic of a relatively tight, complete husk cover and germplasm possessing the characteristic of a relatively loose, incomplete husk cover on the ear were evaluated for 3 years at Tifton, GA, for aflatoxin contamination. In two of the three test years, corn ears with tight, complete husk cover sustained significantly lower mean amounts of aflatoxin than ears with loose, incomplete husk cover following artificial inoculation with Aspergillus flavus Link spores. Ears hand-infested with maize weevils, Sitophilus zeamais (Motschulsky), sustained significantly higher amounts of aflatoxin (329 ng·g−1) than ears infested with fall armyworms, Spodoptera frugiperda (J. E. Smith), (80 ng·g−1), European corn borers, Ostrinia nubilalis (Hübner), (71 ng·g−1), or corn earworms Heliothis zea (Boddie) (60 ng·g−1). Overall, ears in the check (inoculated with A. flavus only) sustained significantly lower aflatoxin (37 ng·g−1) amounts than ears from plots supplemented with insects. Although insects were not applied in the check plots, some damage was observed on the ears.


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