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S N Okiwelu - One of the best experts on this subject based on the ideXlab platform.
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attractancy of diethylether and hexane extracts of maize zea mays l to Oryzaephilus Mercator fauve1 coleoptera silvanidae
Scientia Africana, 2011Co-Authors: O C Umeozor, P O Pessu, S N OkiweluAbstract:Diethylether and hexane extracts of maize attracted 1-7 and 28-42 day-old Oryzaephilus Mercator adults. The 1-7 day-old adults were significantly more responsive than the 28- 42 day-old. Starvation of adults for up to 3 days progressively increased O. Mercator response. Hexane extracts were more attractive than diethylether extracts. Within the extract concentration range of 0.02, 0.04, 0.06, 0.08, and 1.0ml, optimal response of O. Mercator occurred at 0.06m1 and beyond this level, negative response was observed. There were significant interactions between age and solvent; age and starvation period; solvent and extract concentration; age and extract concentration; starvation period and extract concentration, and among age, solvent, and starvation period; age, solvent, and extract concentration; and solvent, starvation period, and extract concentration. Probable reasons for the results obtained are discussed.
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attractancy of acetone and diethylether extracts of cereals to Oryzaephilus Mercator
Tropical Science, 2006Co-Authors: O C Umeozor, P O Pessu, S N OkiweluAbstract:Acetone and diethylether extracts of maize, millet, sorghum and wheat attracted 1- to 7- and 28- to 42-day-old Oryzaephilus Mercatoradults. The 1- to 7-day adults were significantly more responsive than the 28- to 42-day, and adults starved for up to 3 days showed an increasing response. Diethylether extracts were more attractive than acetone extracts and there was a significant interaction between age and solvent. Copyright © 2006 John Wiley & Sons, Ltd
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attractancy of diethyl ether extracts of arachis hypogaea linnaeus papilionaceae citrullus lanatus thunberg cucurbitaceae and irvingia gabonensis var excelsa baillon irvingiaceae to Oryzaephilus Mercator fauvel coleoptera silvanidae
Journal of Stored Products Research, 1998Co-Authors: P O Dudu, S N Okiwelu, N E S LaleAbstract:Abstract Volatiles of the diethyl ether extracts of I. gabonensis, C. lanatus and A. hypogaea attracted 1–7 and 28–42-day-old adult O. Mercator when tested in a two-choice pitfall Petri dish bioassay. For both age groups, a significant difference was observed in response between fed and starved adults to the different extracts. Differences in starvation time did not affect responses of individuals in the 1–7-day-old group; a significant effect was observed in the 28–42-day-old group. Adults, 28–42-day-old were significantly more responsive to virtually all extracts than 1–7-day-old adults. Responses of adults in each age group to the different extracts were not significantly different. The time of trial within the period 0900–1900 h did not significantly affect the response of adults in both age groups, starved for 2 days, to any extract.
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the effects of photoperiod on some aspects of the biology of Oryzaephilus Mercator fauvel coleoptera silvanidae
Journal of Stored Products Research, 1998Co-Authors: S N Okiwelu, P O Dudu, N E S LaleAbstract:The effects of three photoperiod regimes (24LL, 24DD, LD 12:12) on the duration of the developmental, pre-oviposition and oviposition periods, etc. in Oryzaephilus Mercator were investigated under fluctuating laboratory conditions (25.9-30.2°C and 75.4-85.3% r.h.) on Irvingia gabonensis var. excelsa (African mango), Citrullus lanatus (melon) and Arachis hypogaea (groundnut). The mean egg period was longest in the LD 12:12 regime; the larval and egg-adult periods were shortest in this regime. The egg-adult developmental period was longest in the 24LL regime. Differences in the duration of these developmental stages among the regimes were significant. The mean egg, larval and pupal mortalities were highest in the LD 12:12 regime and lowest in the 24LL regime. The pre-oviposition period was longest in the LD 12:12 regime on all oilseeds; using indices of the number of mean total eggs produced per female and duration of oviposition period, this was also the most ideal regime.
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oviposition of Oryzaephilus Mercator fauvel coleoptera silvanidae on arachis hypogaea l papilionaceae citrullus lanatus thunb cucurbitaceae and irvingia gabonensis var excelsa baillon irvingiaceae
Journal of Stored Products Research, 1998Co-Authors: P O Dudu, S N Okiwelu, N E S LaleAbstract:Abstract Studies on the oviposition of Oryzaephilus Mercator on three commodities ( Irvingia gabonensis var. excelsa, Citrullus lanatus and Arachis hypogaea ) were conducted under fluctuating conditions (20–30 °C and 70%–85% r.h.). The length of the pre-oviposition period was not affected by the type of commodity; however, it was significantly shorter on the milled form than on the whole form of the commodities. Preference for specific oviposition sites on seeds to containers was demonstrated only on I. gabonensis and C. lanatus . The total numbers of eggs and the duration of the oviposition period were significantly higher on I. gabonensis and A. hypogaea than on C. lanatus . The rate of oviposition was higher on milled A. hypogaea than on I. gabonensis and C. lanatus . Unmated females did not lay eggs. The mean oviposition period was significantly longer and the egg numbers were higher in undisturbed mated pairs than in interrupted mated pairs. A variation in sex ratio did not significantly affect the number of eggs laid per female.
N E S Lale - One of the best experts on this subject based on the ideXlab platform.
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attractancy of diethyl ether extracts of arachis hypogaea linnaeus papilionaceae citrullus lanatus thunberg cucurbitaceae and irvingia gabonensis var excelsa baillon irvingiaceae to Oryzaephilus Mercator fauvel coleoptera silvanidae
Journal of Stored Products Research, 1998Co-Authors: P O Dudu, S N Okiwelu, N E S LaleAbstract:Abstract Volatiles of the diethyl ether extracts of I. gabonensis, C. lanatus and A. hypogaea attracted 1–7 and 28–42-day-old adult O. Mercator when tested in a two-choice pitfall Petri dish bioassay. For both age groups, a significant difference was observed in response between fed and starved adults to the different extracts. Differences in starvation time did not affect responses of individuals in the 1–7-day-old group; a significant effect was observed in the 28–42-day-old group. Adults, 28–42-day-old were significantly more responsive to virtually all extracts than 1–7-day-old adults. Responses of adults in each age group to the different extracts were not significantly different. The time of trial within the period 0900–1900 h did not significantly affect the response of adults in both age groups, starved for 2 days, to any extract.
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oviposition of Oryzaephilus Mercator fauvel coleoptera silvanidae on arachis hypogaea l papilionaceae citrullus lanatus thunb cucurbitaceae and irvingia gabonensis var excelsa baillon irvingiaceae
Journal of Stored Products Research, 1998Co-Authors: P O Dudu, S N Okiwelu, N E S LaleAbstract:Abstract Studies on the oviposition of Oryzaephilus Mercator on three commodities ( Irvingia gabonensis var. excelsa, Citrullus lanatus and Arachis hypogaea ) were conducted under fluctuating conditions (20–30 °C and 70%–85% r.h.). The length of the pre-oviposition period was not affected by the type of commodity; however, it was significantly shorter on the milled form than on the whole form of the commodities. Preference for specific oviposition sites on seeds to containers was demonstrated only on I. gabonensis and C. lanatus . The total numbers of eggs and the duration of the oviposition period were significantly higher on I. gabonensis and A. hypogaea than on C. lanatus . The rate of oviposition was higher on milled A. hypogaea than on I. gabonensis and C. lanatus . Unmated females did not lay eggs. The mean oviposition period was significantly longer and the egg numbers were higher in undisturbed mated pairs than in interrupted mated pairs. A variation in sex ratio did not significantly affect the number of eggs laid per female.
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the effects of photoperiod on some aspects of the biology of Oryzaephilus Mercator fauvel coleoptera silvanidae
Journal of Stored Products Research, 1998Co-Authors: S N Okiwelu, P O Dudu, N E S LaleAbstract:The effects of three photoperiod regimes (24LL, 24DD, LD 12:12) on the duration of the developmental, pre-oviposition and oviposition periods, etc. in Oryzaephilus Mercator were investigated under fluctuating laboratory conditions (25.9-30.2°C and 75.4-85.3% r.h.) on Irvingia gabonensis var. excelsa (African mango), Citrullus lanatus (melon) and Arachis hypogaea (groundnut). The mean egg period was longest in the LD 12:12 regime; the larval and egg-adult periods were shortest in this regime. The egg-adult developmental period was longest in the 24LL regime. Differences in the duration of these developmental stages among the regimes were significant. The mean egg, larval and pupal mortalities were highest in the LD 12:12 regime and lowest in the 24LL regime. The pre-oviposition period was longest in the LD 12:12 regime on all oilseeds; using indices of the number of mean total eggs produced per female and duration of oviposition period, this was also the most ideal regime.
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the effects of temperature and humidity on oviposition and developmental period of Oryzaephilus Mercator fauvel
Postharvest Biology and Technology, 1996Co-Authors: N E S Lale, P O Dudu, S N OkiweluAbstract:Abstract In a laboratory assessment of the potential tolerance of the Merchant beetle, Oryzaephilus Mercator (Fauvel), to temperature and humidity, both adults and immature stages were exposed to different levels of these factors. Temperatures investigated were 20, 30 and 37 °C and relative humidities (RHs) were 30, 50, 70 and 90%. There were significant direct and interactive effects of the factors on oviposition so that higher numbers of eggs were laid as both temperature and RH increased. Low temperature and low humidity, however, inhibited the hatching of these eggs, and no larvae were produced at 20 °C and 30% RH, even with prolonged incubation. Temperature appeared to be a more important factor determining the duration of the life-cycle of this beetle as its development was generally quicker with increasing levels of this factor. Oilseeds may be less susceptible to O. Mercator in agroecologies with sub-tropical climates where temperatures and humidities are relatively low.
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susceptibility of three physical forms of three oilseeds to Oryzaephilus Mercator and the effects of infestation on seed quality
Postharvest Biology and Technology, 1996Co-Authors: P O Dudu, N E S Lale, S N OkiweluAbstract:Abstract Three physical forms (whole, broken and milled) of three oilseeds, Irvingia gabonensis (mango), Citrullus lanatus (melon) and Arachis hypogaea (groundnut) were assessed for their relative susceptibility to infestation by the merchant beetle (Oryzaephilus Mercator) under laboratory conditions [25–30 °C and 77–90% relative humidity (RH)]. In addition, whole seeds of each commodity were also infested with adult merchant beetle and stored for three, six and nine months under identical conditions. Higher numbers of eggs were laid on mango seeds and on the broken and milled seeds in comparison with melon and groundnut seeds and the whole seeds, respectively. Development was, however, longer in mango seeds than in melon and groundnut seeds. There were no significant differences in developmental periods of the merchant beetle between the physical forms of the oilseeds. Higher numbers of adults relative to the numbers of eggs laid emerged from groundnut seeds and generally from broken and milled forms of each oilseed. Moisture content increased in oilseeds stored for nine months, whereas protein content of the seeds decreased during the same period. With only occasional exceptions, the oil contents of mango and melon decreased with increasing storage time and infestation. In contrast, the oil content of groundnut generally increased with increasing storage time. The number of adult merchant beetle was usually significantly higher on the commodities as storage time increased. Availability of oil to the immature stages and perhaps seed hardness were suggested as possible factors which influenced the rate of development of this beetle.
P O Dudu - One of the best experts on this subject based on the ideXlab platform.
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attractancy of diethyl ether extracts of arachis hypogaea linnaeus papilionaceae citrullus lanatus thunberg cucurbitaceae and irvingia gabonensis var excelsa baillon irvingiaceae to Oryzaephilus Mercator fauvel coleoptera silvanidae
Journal of Stored Products Research, 1998Co-Authors: P O Dudu, S N Okiwelu, N E S LaleAbstract:Abstract Volatiles of the diethyl ether extracts of I. gabonensis, C. lanatus and A. hypogaea attracted 1–7 and 28–42-day-old adult O. Mercator when tested in a two-choice pitfall Petri dish bioassay. For both age groups, a significant difference was observed in response between fed and starved adults to the different extracts. Differences in starvation time did not affect responses of individuals in the 1–7-day-old group; a significant effect was observed in the 28–42-day-old group. Adults, 28–42-day-old were significantly more responsive to virtually all extracts than 1–7-day-old adults. Responses of adults in each age group to the different extracts were not significantly different. The time of trial within the period 0900–1900 h did not significantly affect the response of adults in both age groups, starved for 2 days, to any extract.
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oviposition of Oryzaephilus Mercator fauvel coleoptera silvanidae on arachis hypogaea l papilionaceae citrullus lanatus thunb cucurbitaceae and irvingia gabonensis var excelsa baillon irvingiaceae
Journal of Stored Products Research, 1998Co-Authors: P O Dudu, S N Okiwelu, N E S LaleAbstract:Abstract Studies on the oviposition of Oryzaephilus Mercator on three commodities ( Irvingia gabonensis var. excelsa, Citrullus lanatus and Arachis hypogaea ) were conducted under fluctuating conditions (20–30 °C and 70%–85% r.h.). The length of the pre-oviposition period was not affected by the type of commodity; however, it was significantly shorter on the milled form than on the whole form of the commodities. Preference for specific oviposition sites on seeds to containers was demonstrated only on I. gabonensis and C. lanatus . The total numbers of eggs and the duration of the oviposition period were significantly higher on I. gabonensis and A. hypogaea than on C. lanatus . The rate of oviposition was higher on milled A. hypogaea than on I. gabonensis and C. lanatus . Unmated females did not lay eggs. The mean oviposition period was significantly longer and the egg numbers were higher in undisturbed mated pairs than in interrupted mated pairs. A variation in sex ratio did not significantly affect the number of eggs laid per female.
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the effects of photoperiod on some aspects of the biology of Oryzaephilus Mercator fauvel coleoptera silvanidae
Journal of Stored Products Research, 1998Co-Authors: S N Okiwelu, P O Dudu, N E S LaleAbstract:The effects of three photoperiod regimes (24LL, 24DD, LD 12:12) on the duration of the developmental, pre-oviposition and oviposition periods, etc. in Oryzaephilus Mercator were investigated under fluctuating laboratory conditions (25.9-30.2°C and 75.4-85.3% r.h.) on Irvingia gabonensis var. excelsa (African mango), Citrullus lanatus (melon) and Arachis hypogaea (groundnut). The mean egg period was longest in the LD 12:12 regime; the larval and egg-adult periods were shortest in this regime. The egg-adult developmental period was longest in the 24LL regime. Differences in the duration of these developmental stages among the regimes were significant. The mean egg, larval and pupal mortalities were highest in the LD 12:12 regime and lowest in the 24LL regime. The pre-oviposition period was longest in the LD 12:12 regime on all oilseeds; using indices of the number of mean total eggs produced per female and duration of oviposition period, this was also the most ideal regime.
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the effects of temperature and humidity on oviposition and developmental period of Oryzaephilus Mercator fauvel
Postharvest Biology and Technology, 1996Co-Authors: N E S Lale, P O Dudu, S N OkiweluAbstract:Abstract In a laboratory assessment of the potential tolerance of the Merchant beetle, Oryzaephilus Mercator (Fauvel), to temperature and humidity, both adults and immature stages were exposed to different levels of these factors. Temperatures investigated were 20, 30 and 37 °C and relative humidities (RHs) were 30, 50, 70 and 90%. There were significant direct and interactive effects of the factors on oviposition so that higher numbers of eggs were laid as both temperature and RH increased. Low temperature and low humidity, however, inhibited the hatching of these eggs, and no larvae were produced at 20 °C and 30% RH, even with prolonged incubation. Temperature appeared to be a more important factor determining the duration of the life-cycle of this beetle as its development was generally quicker with increasing levels of this factor. Oilseeds may be less susceptible to O. Mercator in agroecologies with sub-tropical climates where temperatures and humidities are relatively low.
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susceptibility of three physical forms of three oilseeds to Oryzaephilus Mercator and the effects of infestation on seed quality
Postharvest Biology and Technology, 1996Co-Authors: P O Dudu, N E S Lale, S N OkiweluAbstract:Abstract Three physical forms (whole, broken and milled) of three oilseeds, Irvingia gabonensis (mango), Citrullus lanatus (melon) and Arachis hypogaea (groundnut) were assessed for their relative susceptibility to infestation by the merchant beetle (Oryzaephilus Mercator) under laboratory conditions [25–30 °C and 77–90% relative humidity (RH)]. In addition, whole seeds of each commodity were also infested with adult merchant beetle and stored for three, six and nine months under identical conditions. Higher numbers of eggs were laid on mango seeds and on the broken and milled seeds in comparison with melon and groundnut seeds and the whole seeds, respectively. Development was, however, longer in mango seeds than in melon and groundnut seeds. There were no significant differences in developmental periods of the merchant beetle between the physical forms of the oilseeds. Higher numbers of adults relative to the numbers of eggs laid emerged from groundnut seeds and generally from broken and milled forms of each oilseed. Moisture content increased in oilseeds stored for nine months, whereas protein content of the seeds decreased during the same period. With only occasional exceptions, the oil contents of mango and melon decreased with increasing storage time and infestation. In contrast, the oil content of groundnut generally increased with increasing storage time. The number of adult merchant beetle was usually significantly higher on the commodities as storage time increased. Availability of oil to the immature stages and perhaps seed hardness were suggested as possible factors which influenced the rate of development of this beetle.
A S Lapenta - One of the best experts on this subject based on the ideXlab platform.
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genetic variability in esterases and the insecticide resistance in brazilian strains of Oryzaephilus Mercator and Oryzaephilus surinamensis coleoptera silvanidae
Bulletin of Entomological Research, 2011Co-Authors: G A R Silva, A S LapentaAbstract:Oryzaephilus Mercator and O. surinamensis are stored grains and processed food pests, the latter being responsible for major economical losses. Polyacrylamide gel electrophoresis was used to analyse esterase patterns during insect development. Seven esterases, three cholinesterases, two carboxylesterases and two acetylesterases, were identified in O. Mercator , one of which was proper to adults. Five esterases, of which four were cholinesterases, occurred in O. surinamensis. Strains of O. Mercator and O. surinamensis were also exposed to malathion and chlorpyrifos-methyl. According to the LC 50 estimates, OmLC-M and OmLA strains of O. Mercator and OsLB strain of O. surinamensis were the most resistant to both insecticides. However, higher sensitivity to malathion and chlorpyrifos-methyl has also been verified in some of its esterases. Cholinesterases OmEST-1 and OsEST-5 seem to be involved in this resistance. These results suggest that organophosphate tolerance may be related to genetic variability in esterase isoenzymes.
Shanas Tanzilia - One of the best experts on this subject based on the ideXlab platform.
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Seed coat and variety of peanut inhibits host preference and development of Oryzaephilus Mercator
Journal of Stored Products Research, 2018Co-Authors: Ludji Pantja Astuti, Akhmad Rizali, Shanas TanziliaAbstract:Abstract Oryzaephilus Mercator (Fauvel) (Coleoptera: Silvanidae) is a postharvest pest of stored peanuts (Arachis hypogea L.). Although it is only a secondary pest, this insect causes extensive damage and reduces the quantity and quality of peanut kernels. The objective of this research was to study whether host preference and development of O. Mercator differ depending on the variety of peanut and/or on whether the peanut retains its seed coat or is bare. We used three varieties of peanut (Kelinci, Bison and Takar1) separating out each variety into groups with or without a seed coat. In the laboratory, we conducted two separate studies examining host preference and development of O. Mercator. Host preference was studied using a preference cage consisting of six chambers for all peanut varieties with and without seed coat and each cage contained 15 mating pairs of O. Mercator. The development study was conducted by placing 15 mating pairs of O. Mercator into a treatment jar and allowing them to feed on different peanut varieties with and without a seed coat. Results from the host preference study indicated that O. Mercator preferred bare kernels of the Kelinci variety over other peanut varieties both as a food source and for oviposition. During the development experiment, we observed that O. Mercator experienced faster development time when exposed to bare kernels of all three varieties tested as opposed to those with intact seed coat. Results show that peanuts with a seed coat and variety with high kernel hardness (Bison variety) deters predation and inhibits host preference and development of O. Mercator.
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Oryzaephilus Mercator fauvel coleoptera silvanidae preferensi pertumbuhan dan perkembangannya pada tiga varietas kacang tanah dalam simpanan
2016Co-Authors: Shanas TanziliaAbstract:Kacang tanah (Arachis hypogea L.) merupakan komoditas yang penting di Indonesia. Kacang tanah memiliki berbagai kegunaan antara lain sebagai bahan makanan bagi manusia, bahan pakan ternak, dan bahan dasar pembuatan minyak nabati. Produksi kacang tanah di Indonesia mengalami penurunan dalam beberapa tahun. Penurunan tersebut salah satunya dapat diakibatkan oleh serangan hama pascapanen. Hama pascapanen yang menyerang kacang tanah salah satunya adalah Oryzaephilus Mercator (Fauvel) (Coleoptera: Silvanidae). Kacang tanah di dalam simpanan terdiri dari berbagai varietas yang memiliki kandungan nutrisi berbeda. Di sisi lain, kacang tanah umumnya disimpan dalam kondisi berkulit dan tanpa kulit ari. Perbedaan nutrisi dan keberadaan kulit ari dari kacang tanah dapat berpengaruh terhadap preferensi, pertumbuhan dan perkembangan hama O. Mercator. Penelitian dilaksanakan di Laboratorium Hama Tumbuhan, Jurusan Hama dan Penyakit Tumbuhan, Fakultas Pertanian, Universitas Brawijaya mulai bulan Januari hingga Juli 2016. Perlakuan dalam penelitian terdiri dari 3 varietas kacang tanah yaitu varietas Kelinci, Bison, dan Takar 1 berkulit dan tanpa kulit ari. Pada penelitian preferensi, 30 g pakan sesuai perlakuan dimasukkan ke dalam sangkar preferensi selanjutnya sangkar diinfestasikan dengan 15, 30, dan 45 pasang imago berumur tujuh sampai 14 hari. Pada penelitian pertumbuhan dan perkembangan, 30 g pakan sesuai perlakuan dimasukkan dalam tabung perlakuan selanjutnya pakan diinfestasi dengan 15 pasang imago O. Mercator berumur tujuh sampai 14 hari. Berdasarkan hasil penelitian preferensi diketahui bahwa Imago O. Mercator lebih menyukai kacang tanah varietas Kelinci tanpa kulit ari daripada perlakuan lain untuk hadir dan meletakkan telur. Hasil uji korelasi menunjukkan adanya hubungan antara jumlah imago betina yang hadir dengan jumlah telur yang diletakkan. Berbeda dengan hasil pada penelitian preferensi, pertumbuhan dan perkembangan O. Mercator lebih baik pada kacang tanah varietas Kelinci, Bison, dan Takar 1 tanpa kulit ari daripada perlakuan lain. Keberadaan kulit ari mempengaruhi preferensi, pertumbuhan, dan perkembangan hama O. Mercator. Kacang tanah dengan kulit ari yang tebal dapat menghambat aktifitas makan serangga O. Mercator sehingga dapat menyebabkan kematian serangga. Hasil uji ketebalan kulit ari, menunjukkan bahwa kacang tanah varietas Takar 1 berkulit ari memiliki kulit ari lebih tebal daripada perlakuan lain yaitu 0,092 mm. Keberadaan kulit ari, juga mempengaruhi tingkat kekerasan dari kacang tanah. Hasil uji kekerasan biji kacang tanah menunjukkan bahwa kacang tanah varietas Bison dan Takar 1 berkulit ari memiliki tingkat kekerasan lebih tinggi daripada perlakuan lain yaitu 126,10 dan 105,94 N. Kematian pada serangga yang diinfestasikan akan berpengaruh terhadap jumlah telur, larva, pupa, dan imago baru yang dihasilkan. Kacang tanah dengan kulit ari yang tebal dan tingkat kekerasan yang tinggi kurang sesuai untuk pertumbuhan dan perkembangan serangga O. Mercator.