The Effect of Sitophilus Zeamais (Mots) (Coleoptera: Curculionidae) on the Quality and Viability of Stored Maize in Nigeria

  • S. N. Okiwelu
  • O. O. Adu
  • V. N. Okonkwo
Research Article


The effect of 10, 20, 30, 40, and 50 adult Sitophilus zeamais on the quality of 1 kg lots of white maize maintained at 25-30°C and 65-85% r.h. was observed. Per cent moisture, oil, Free Fatty Acid (FFA) content and germination were determined at 2-week intervals for 10 weeks.

Moisture content of infested maize ranged from 11.51 to 12.92%, There was a significant correlation between moisture content and degree of infestation (r =0.88; P < 0,05; Y = 11.908 + 0.006 x). The range of oil content of infested maize was 4.83-5.75%. There was a significant correlation between oil content and degree of infestation (r = -0.097; P < 0,05; Y = 5.08 -0.0076 x). The free fatty acid (FFA) of infested maize was 5.82-6.86%. The heterogeneity at various infestation levels was significant (F = 81.38; d.f. — 5; P < 0.001). There was an increase in FFA, with increasing infestations, although the correlation was not significant.

The germination of maize, 10 days after planting, at various infestation levels was 43.0-97.5%. There was a decrease in germination, as level of infestation increased. The heterogeneity in germination at various infestation levels was significant (F = 19.21; d.f. — 5; P < 0.001). Possible reasons for the results obtained, are presented.

Key Words

Sitophilus zeamais moisture content degree of infestation heterogeneity in germination 


L’effet de 10, 20, 30, 40, et 50 adultes de Sitophilus zeamais sur la qualité de 1 kg de maîs blac a été observé. Le pourcentage d’humidité, la teneurs en lipides, acides gras libres et le pourcentage de germination ont été déterminés à intervalles de deux semaines pendant 10 semaines.

Le pourcentage d’humidité de maîs infesté variait de 11,5 à 13,1, Il y avait une corrélation significative entre le pourcentage d’humidité et le degré d’infestation (r = 0,88; p < 0,05; Y = 11,908 + 0,006 x). La variation de teneur en huile du maîs infesté était de 4,4-5,5%. Il y avait une corrélation significative entre la teneur en huile et le degré d’infestation (r = 0,065; p < 0,05; Y = 5,08 — 0,0076 x). Le pourcentage en acides gras libres dans le maîs infesté était de 5,8-6,9%. L’hétérogénéité à divers niveau d’infestation était significative (F = 81,38; d.d.l. = 5; p < 0,001). Il y avait une augmentation dans le pourcentage d’acides gras libres lorsque l’infestation augments, bien que la corrélation ne soit pas significative.

Le pourcentage de germination du maîs dix jours après semis à divers niveau d’infestation était de 43-98%. Il y avait une diminution dans le pourcentage de germination lorsque le taux d’infestation augmente. L’hétérogénéité dans le pourcentage de germination à divers niveau d’infestation était significative (F — 19,21; d.d.l. = 5; p < 0,001). La signification de ces résultats est discutée.

Mots Cléfs

Sitophilus zeamis teneur en humidite degre d’infestation heterogéneité dans la germination. 


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Copyright information

© ICIPE 1987

Authors and Affiliations

  • S. N. Okiwelu
    • 1
  • O. O. Adu
    • 2
  • V. N. Okonkwo
    • 1
  1. 1.Department of ZoologyUniversity of Port HarcourtPort HarcourtNigeria
  2. 2.Nigerian Stored Products Research InstitutePort HarcourtNigeria

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