Survival of Rhyzopertha dominica (Coleoptera: Bostrichidae) in Stored Wheat Under Fall and Winter Temperature Conditions

1994 ◽  
Vol 23 (2) ◽  
pp. 390-395 ◽  
Author(s):  
David W. Hagstrum ◽  
Paul W. Flinn
Keyword(s):  
Winter Temperature ◽  
Rhyzopertha Dominica ◽  
Stored Wheat ◽  
Temperature Conditions

Delayed germination in seeds of Phacelia dubia var. dubia

1973 ◽  
Vol 51 (12) ◽  
pp. 2481-2486 ◽  
Author(s):  
Jerry M. Baskin ◽  
Carol C. Baskin
Keyword(s):  
Life Cycle ◽  
Seedling Establishment ◽  
Winter Temperature ◽  
Seed Crop ◽  
Temperature Conditions ◽  
Secondary Dormancy ◽  
Winter Temperatures ◽  
Winter Annual ◽  
Delayed Germination ◽  
Germinating Seeds

Not all seeds of a particular seed crop of the winter annual Phacelia dubia var. dubia germinate the first autumn after their dispersal in spring, and germination of a given seed crop is spread over several years. Nondormant seeds that do not germinate in autumn are induced into secondary dormancy by low winter temperatures and must afterripen again during summer before they are capable of germinating. Seeds that do not afterripen the first summer after dispersal are prevented from doing so until at least the next summer because winter temperature conditions prevent afterripening. These responses of the seeds to the environment insure that germination will occur only in autumn, the only season of the year that is suitable for seedling establishment and eventual completion of the life cycle.

Changes in stored-wheat ecosystems infested with two combinations of insect species

1980 ◽  
Vol 58 (9) ◽  
pp. 1524-1534 ◽  
Author(s):  
N. D. G. White ◽  
R. N. Sinha
Keyword(s):  
Carbon Dioxide ◽  
Sitophilus Oryzae ◽  
The Other ◽  
Rhyzopertha Dominica ◽  
Cryptolestes Ferrugineus ◽  
Oryzaephilus Surinamensis ◽  
Stored Wheat ◽  
Seed Damage ◽  
Grain Moisture ◽  
Multiple Species

The consequences of infestation of bulk-stored wheat by multiple species of insects were determined for 60 weeks at 30 ± 2 °C. Eight 204-L drums containing wheat at 15.5% moisture content were used as three distinct systems: (I) Control system (two drums), insect free; (II) RST system (three drums), infested with the grouping of Rhyzopertha dominica F., Sitophilus oryzae (L.), and Tribolium castaneum (Herbst); and (III) COT system (three drums), infested with the grouping of Cryptolestes ferrugineus (Stephens), Oryzaephilus surinamensis (L.), and T. castaneum. At triweekly intervals carbon dioxide, oxygen, temperature, grain moisture, seed damage, grain weight, dust weight, fat acidity values (FAV), seed germination, microflora, and the numbers of insects and the mite Tarsonemus granarius Lindquist were measured. Seeds died by week 15 and bacterial infection on them increased in all systems. The seed FAVs in the RST system peaked by week 30 and then declined steadily while these values were increasing continuously in the Control and levelling off in the COT systems. Insects multiplied exponentially for 6–15 weeks and then declined sharply or maintained oscillating populations; Sitophilus and Oryzaephilus were unable to survive in the presence of the other insects.

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