• BMB Reports
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• v.40 no.5
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• pp.773-782
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• 2007

Different isolates of the soil bacterium Bacillus thuringiensis produce multiple crystal (Cry) proteins toxic to a variety of insects, nematodes and protozoans. These insecticidal Cry toxins are known to be active against specific insect orders, being harmless to mammals, birds, amphibians, and reptiles. Due to these characteristics, genes encoding several Cry toxins have been engineered in order to be expressed by a variety of crop plants to control insectpests. The cotton boll weevil, Anthonomus grandis, and the fall armyworm, Spodoptera frugiperda, are the major economically devastating pests of cotton crop in Brazil, causing severe losses, mainly due to their endophytic habit, which results in damages to the cotton boll and floral bud structures. A cry1Ia-type gene, designated cry1Ia12, was isolated and cloned from the Bt S811 strain. Nucleotide sequencing of the cry1Ia12 gene revealed an open reading frame of 2160 bp, encoding a protein of 719 amino acid residues in length, with a predicted molecular mass of 81 kDa. The amino acid sequence of Cry1Ia12 is 99% identical to the known Cry1Ia proteins and differs from them only in one or two amino acid residues positioned along the three domains involved in the insecticidal activity of the toxin. The recombinant Cry1Ia12 protein, corresponding to the cry1Ia12 gene expressed in Escherichia coli cells, showed moderate toxicity towards first instar larvae of both cotton boll weevil and fall armyworm. The highest concentration of the recombinant Cry1Ia12 tested to achieve the maximum toxicities against cotton boll weevil larvae and fall armyworm larvae were 230 ${\mu}g/mL$ and 5 ${\mu}g/mL$, respectively. The herein demonstrated insecticidal activity of the recombinant Cry1Ia12 toxin against cotton boll weevil and fall armyworm larvae opens promising perspectives for the genetic engineering of cotton crop resistant to both these devastating pests in Brazil.

• Korean journal of applied entomology
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• v.52 no.4
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• pp.371-377
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• 2013

Occurrence of adult alfalfa weevil, Hypera postica Gyllenhal, was observed at Chinese milk vetch field, and host plant preference of its $1^{st}$ generation adult was observed at greenhouse and Chinese milk vetch field. The over-wintered adult of the weevil appeared from late March and peaked in mid April while the $1^{st}$ generation adult appeared from late April and peaked in late May. However, the occurrence of over-wintered adult was very low contrary to the $1^{st}$ generation adult which was very high with some variations among observed years. In greenhouse, host plant preference of $1^{st}$ adult generation of H. postica was evaluated with 11 different seedlings. H. postica was found to occur in significantly higher number on Chinese cabbage seedling followed by soybean, and kale at 7 days after releasing(DAR). Corn, crown daisy and sorghum were found to be the least preferred with nil occurrence of the weevil. Seedlings damage rate by H. postica feeding at 7DAR was the most severe on Chinese cabbage(60.0%) followed by soybean(50.0%), kale(30.0%), foxtail millet(16.7%), proso millet(13.3%) and lettuce(3.3%) significantly. Also, seedlings damage rate by H. postica at 7DAR in Chinese milk vetch field had shown the similar trend with Chinese cabbage(46.7%), soybean(43.3%), kale(23.3%), foxtail millet(13.3%) and proso millet(13.3%) in greenhouse significantly. Accordingly, results on host plant preference of H. postica from this study can be used as a basic information for safe cultivation of upland crops at near or around green manure crop field.

• 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.

• Korean journal of applied entomology
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• v.28 no.1
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• pp.28-31
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• 1989

Lariophagus distinguendus,an ectoparasitoid of rice weevil, laid its eggs exclusively on the third and fourth larvae, with the preference for the fourth larva. The sex ratio of the pa¬rasitoid can be regulated by the female parasitoid on the basis of the host size available at the time of oviposition.

• Korean journal of applied entomology
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• v.27 no.1
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• pp.14-20
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• 1988

쌀바구미 생명표 통계량을 정온 조건과 실온 조건에서 산출하였다. 온일도를 단위로 하였을 때 $20^{\circ}$~ $30^{\circ}$ 범위내 정온 조건에서의 통계량은 실온 조건에서의 통계량과 유사한 차이를 보이지 않았으며 온도간의 변이는 실온에서의 간 변이와 유사하였다. 이 결과는 온일도를 시간단위로 할 때 쌀바구미의 생화사가 표준화 될 수 있음을 시사하는 것이었다. 쌀바구미는 $368pm$41.2DD에서 산란을 시작하여 $1391.0\pm$38.7DD에서 멈추는 것으로 추정되었다. 외적 자연회가졸 밀도 음가 기간과 평균세대 기간은 각각$ 0.0052\pm$0.0006/DD, $134.7\pm$15.0 DD 그리고 $715.2\pm$53.6 DD인 것으로 산출되었다.

• Bulletin of the Korean Chemical Society
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• v.8 no.6
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• pp.487-488
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• 1987

• International Journal of Industrial Entomology and Biomaterials
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• v.47 no.1
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• pp.12-24
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• 2023

Sitophilus oryzae L. (Rice Weevil) is a stored pest of rice that causes extensive loss throughout the world. We tested the leaf powders of 12 plant species viz., Chrysanthemum sp., Cinnamomum zeylanicum, Citrus grandis, Citrus limon, Gliricidia sepium, Gymnema sylvestre, Hemigraphis colorata, Michelia champaca, Moringa oleifera, Murraya koenigii, Polyalthia longifolia, and Sauropus androgynus at dosages of 1.00, 1.50, 2.00 and 3.00g against the adult rice weevil and mortality was recorded at 1, 2, 3, 5, 7, 12 and 2l days after treatment (DAT) by direct contact toxicity for their adulticidal effect. We observed 100 percent adult mortality in C. zevlanicum and M. koenigii among the tested leaf powders. In addition, the first-time tested H. colorata and S. androgynus also caused high mortality compared to other plants. All the plant powders caused moderate to high adult mortality. Hence, these plants could be effective botanical insecticides against S. oryzae as they comprise a potential source of bioactive chemicals and are generally free from toxicants. Applications of these natural derivatives in S. oryzae control could reduce the cost of control methods and storage of rice contamination. Therefore, the present study indicates that some plant extracts can be used as an alternative to toxic synthetic chemicals in the management of rice weevils.

• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.147-151
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• 2007

Laboratory tests were conducted to determine the susceptibility of the alfalfa weevil, Hypera postica to Korean entomopathogenic nematodes, Steinernema carpocapsae GSN1 strain (ScG), S. glaseri Dongrae strain (SgD), Heterorhabditis bacteriophora Hamyang strain (HbH), and Heterorhabditis sp. Gyeongsan strain (HeG) at the petri dish assay. The larval mortality of H. postica was significantly different depending on nematode species and treatment concentration. SgD and HeG strain were more effective against H. postica larva than ScG and HbH strain. When SgD and HeG strain were treated with the rate of >20 infective juveniles (ijs) per alfalfa weevil larva, mortality was ca. 77.5-100% at the late instars of H. postica in 3 days. The number of established nematode was significantly different depending on nematode species, whereas number of progeny was not significantly different. The mean number of established us of SgD strain in a host was the highest at 80 ijs by 30.2. The highest progeny number of HeG strain was 2,671.5 with 80 ijs. All nematode strains were not parasitic entirely to H. postica adults. These results show that alfalfa weevil late larva is highly susceptible to Korean entomopathogenic nematodes in the laboratory.

• Korean journal of applied entomology
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• v.47 no.1
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• pp.23-29
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• 2008

The biology of indian meal moth and maize weevil on the trehalose gene introduced rice (var 'Nakdong') (T-Nakdong) was compared to that on the rice without gene introduction (Nakdong) at $28{\pm}1.0^{\circ}C$. Development of the both two insects was significantly delayed; on T-Nakdong, the developmental periods of female moth $({\pm}SE)$ and weevil were $38.46{\pm}0.42\;and\;36.38{\pm}0.28days$, respectively. Whereas those on Nakdong were $36.38{\pm}0.28\;and\;34.33{\pm}0.18$, respectively. Net reproduction rate of Indian meal moth on T-Nakdong $(3.0{\pm}0.14)$ was significantly lower than that on Nakdong $(9.25{\pm}0.13)$, due to the lower emergence rate $(21.08{\pm}0.04%\;vs\;48.30{\pm}0.06%)$. The life table statistics of maize weevil on T-Nakdong was estimated to be similar to those on Nakdong. The delayed development of T-Nakdong suggested that the factor for development of the insects could be changed by the introduction of trehalose gene into the rice variety.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2000.05a
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• pp.43-43
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• 2000