• Korean journal of applied entomology
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• v.42 no.4
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• pp.329-334
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• 2003

To study the interaction between rice weevil and storage molds, the preference of rice weevil to the four mold species (Aspergilus candidus, A. niger, A. flavus and Penicillium spp.) and the resulting reproduction of the rice weevil were observed. The rice weevil preferred rice grains contaminated with the molds to autoclaved ones regardless of the mold species tested. Among the four mold species, A. candidus and Penicillium sp. were highly preferred than the others. Reproduction of the rice weevil was higher on the grains contalminated with A. candidus and Penicillium sp., than on autoclaved ones, but was lower on the grains contaminated with A. flavus. The partial disagreement between preference and reproduction of the rice weevil might be a suggestion that both the weevil behavior adapting nutritional requirements and the process of the long intensive coadaptation of the rice weevil and storage molds requiring similar moisture niche are the major components of the population interaction between the weevil and molds.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.4
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• pp.370-374
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• 1990

A field experiment was conducted to investigate the influence of water weevil damage on growth and grain guality in rice. Plant height was shortened, number of tillers per hill decreased and maximum tillering stage delayed in damaged field by rice water weevil. Heading date was delayed by 1-2days, culm lenght shortened, panicle lengthened, number of panicles decreaced, number of panicles per spikelet increased, ripened grain ratio decreased in damaged field by rice water weevil. Yield per 10a was decreased 4-22% in damaged field compared with that in undamaged field by rice water weevil, yield loss in late transplanting (June 23) was larger than that in early transplanting (May 20). Imperfect kerml rice, especially green kernel rice, was increased in damaged field by rice water weevil.

• Korean Journal of Food Science and Technology
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• v.17 no.5
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• pp.399-402
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• 1985

Polished rice was stored for 24 weeks at $28^{\c수분함량이 16.0% after infestation with rice weevil (Sitophilus oryzae), inoculation with a storage mold, or both treatment. The moisture contents of stored rice with and without rice weevil were 16.6%-17.3% and 13.70%-14.1% respeotively. Fungal numbers were $4.3{\times}10^{6}$/g to $7.2{\times}10^{6}$/g with insects while no fungal growth occurred without them. There were considerable differences between rice weevil infested- and non-infested rice in rice kernel hardness, 1000 kernel weight, maximum viscosity on amylogram, reducing sugar content, fat acidity, and n-hexanal content in head space gas.

• Applied Biological Chemistry
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• v.32 no.3
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• pp.265-269
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• 1989

Effects of air-tighteness of packing material and aluminum phosphide fumigation on mortality of rice weevil were studied during rice storage. Air-tight storage of rice in sealed bag of 0.1mm PE film or sealed glass bottle reduced the deterioration of rice quality and killed all rice weevils after 60 days storage, while paper bag, PP bag and straw bag storage kept them alive. One tablet of aluminum phosphide in one cubic meter heap of rice packed in PP bag was sufficient to kill all rice weevil in it, when the heap was covered by 0.15 mm PE film during fumigation.

• Applied Biological Chemistry
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• v.25 no.4
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• pp.257-260
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• 1982

During the rice storage at $28^{\cir}{\pm}1^{\cir}C$ and $60{\sim}70%$ R.H., the moisture content of rice, was increased max. 1. 6% by the activity of rice weevil. The growth of Asp. repens was not affected, while Asp. niger was inhibited after the appearance of its second generation adults. The development of rice weevil was generally accelerated by both of Asp. repens and Asp. niger, but decelerated at higher density of Asp. niger($1.6{\times}10^4$ propagules/g). The total number of rice weevil showed no significant difference during six weeks.

• Korean journal of applied entomology
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• v.29 no.3
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• pp.176-179
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• 1990

Seasonal occurrence in each stages of rice water weevil, Lissorhoptrus oryzophilus Kuschel, was studied in paddy field transplanted on May 25, Siehung, 1989. The peak of overwintered adults was late May an that of newly emerged adults was early August. Oviposition occurred in late May and late June and its peak was observed on early June. Larvae were observed from early June to early August and pupation occurred from early July to late August. The first adults of newly emerged rice water weevil was observed on early July and its emergence peak was early August.

• Korean journal of applied entomology
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• v.31 no.2
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• pp.139-143
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• 1992

Feeding plants of rice water weevil(RWW) adult and larvae were observed. Thirteen families including 104 species were found as host plants of RWW adult, and 74 species of them were newly identified as its host. Thmedia triandra var. japonica, Luzula capitata, Agropyron tsukushiense var. ransiens, and Zoysiama crostachya were most favorable hosts of adult RWW. Host plants for larvae were 9 species of weeds including Cperus nipponicus, Eleccharis kuroguwa, Sagittaria trifolia, and Claviceps purpurea in the rice paddy fields.

• Korean journal of applied entomology
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• v.36 no.3
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• pp.215-223
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• 1997

A matrix model of rice weevil population based on degree day (DD) was constructed. The basic matrix model predicted on exponential jncrcase of the adult weevil density and the finite rate of increase(h) of the population was estimated to be 2.155/100DD. Adult density simulated by the matrix model including intraspecific competition showed a damped oscillation over time and reached at the stationary level of 530 at 69, 300DD. The experimental population showed similar features to that of the model. But there were some differences in the highest density and period of adult oscillation. The differences could largely be caused by the assumption of the model; resource constancy.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.914-917
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• 2001

The rice water weevil, Lissorhoptrus oryzophillus are major pests of aquatic rice plant throughout the country. In field, we examined efficacy of Steinernema carpocapsae and Xenorhabdus nematophilus against rice water weevil, Lissorhoptrus oryzophilus. Steinernema carpocapsae showed 71-74.2% mortality after 15days in the field. Also symbiotic bacteria Xenorhabdus nematophilus isolated from Steinernema carpocapsae showed 33.3-58.3% mortality after 15days at vat against rice water weevil, Lissorhoptrus oryzophilus.

• Korean journal of applied entomology
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• v.13 no.2 s.19
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• pp.71-75
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• 1974

A study was conducted to investigate the relationships between the rice weevil and associated storage molds. The results are as follows; 1. All of the developmental stages of the rice weevils are carrying some storage molds in their bodies, and the order of magnitute in the number was the adult, larva and pupa. 2. The molds persist in the body of the rice weevil for 10 days who.1 they were fed on the mold free wheat, and the most persistant mold species was A. candidus. 3. When the mold free weevils were reared on the pure culture of the molds on the wheat, the number of eggs laid by the Lveevil were the greatest for A. candidus. following A. ruber, and the . least number Lvere obtained with A. niger 4. The rice weevil could complete in the pure mold culture on the wheat except for A. niger where the larvae had developed by 2nd or 3rd instars. 3. The shortest developmental periods was obtained with A. candidus and the first adult emerged in 4th week. 6. The unfavorable effects of A. niger on the development of the rice weevil might be associated with the fast growth of the mold together with some unknown effects. 7. There seems to be a protocooperative interaction between these two oraganisms having been developed through the long evolutionary course in common habitat.