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Effects of Host and Non-Hosts Plant Volatiles on the Behaviour of the Lesser Grain Borer, Rhyzopertha dominica (Fab.)



D.A. Ukeh and S.B.A. Umoetok
 
ABSTRACT

Single choice behavioural responses of the lesser grain borer Rhyzopertha dominica (Coleoptera: Bostrichdae) to host and non-hosts plant volatiles was studied in a four-choice airflow olfactometer in the laboratory. The host plants odour sources were 30 g maize seeds and 30 g winter wheat kernels, while the non-hosts plant odour sources were 30 g dried Piper guineense and 30 g dried Monodora myristica seeds, respectively. Also 10% (w/w) of each non-host plant was incorporated with host plant grains and tested against R. dominica male and female adults. Results showed that both male and female adult R. dominica were significantly (p<0.001) repelled by P. guineense and M. myristica alone and also when 10% (w/w) of these plant seeds were incorporated with 30 g maize and winter grains, respectively. Both sexes also significantly (p<0.0001) preferred maize and winter wheat seeds to the control in the mean time spent and the number of entries made to their odour zones.

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D.A. Ukeh and S.B.A. Umoetok , 2007. Effects of Host and Non-Hosts Plant Volatiles on the Behaviour of the Lesser Grain Borer, Rhyzopertha dominica (Fab.). Journal of Entomology, 4: 435-443.

DOI: 10.3923/je.2007.435.443

URL: https://scialert.net/abstract/?doi=je.2007.435.443

INTRODUCTION

Farmers in many parts of Africa traditionally dry and store grains and cereals in open storage facilities holding between 500-1500 kg of harvested products. Storing grain is not only an activity to increase food security, it can also be considered, from the farmer’s perspective, as an investment of time and material from which a profit is expected. In West Africa, grains sold 6 months after harvest, when grain is relatively scarce, generally commands a much higher price than grains sold at the time of harvest, when grains and other foods are plentiful (Meikle et al., 2002; Law-Ogbomo and Enobakhare, 2006). More than 600 species of beetles and 70 of moths among the insects, 355 species of mites, 40 species of rodents and 150 species of fungi have been reported to be associated with various stored products (Rajendran, 2005). Although the diversity of insects is high in the granaries in the sub-region, Rhyzopertha dominica (Fab.) has been reported as one of the major pests of stored grains such as maize, wheat, rice, sorghum, legumes and dried cassava (Haines, 1991; Arthur et al., 2006). This insect can penetrate many types of packaging material such as jute bags and both larvae and adults consume grain-based products resulting in fragmented kernels, powdery residues and a characteristic pungent odour. The complete life history of R. dominica has been reported to be approximately one month under optimum conditions (Howe, 1950; Rajendran, 2005). Unlike Sitophilus zeamais (Mostch.), there is little evidence that R. dominica infests ripening grains in the field (Hagstrum, 2001); therefore infestation in storage emanates from either a failure to destroy residual populations from the granaries or from dispersing individuals exploiting unprotected stored grains. This rapid colonization behaviour, strong flight ability and broad polyphagy, coupled with the fact that R. dominica has been trapped in diverse environments, including wood-lands substantial distances from grain stores (Cogburn, 1988), suggests the movement of this insect pest between potential natural habitats and grain storage facilities. This movement by R. dominica is enhanced by the male-produced aggregation pheromones and host plant volatiles in storage houses (Landolt, 1997; Bashir et al., 2001). Males produce the aggregation pheromone upon location of a suitable food source for feeding and breeding (Edde et al., 2005, 2007). The aggregation pheromones of R. dominica were identified as (S)-(+)-1-methylbutyl (E)-2-methyl-2-heptanoate and (S)-(+)-1-methylbutyl (E)-2,4-dimethyl-2-pentanoate (Khorramshahi and Burkholder, 1981; Williams et al., 1981; Razkin et al., 1996). The two pheromone blends are commonly referred to as Dominicalure-1 or DL1 and Dominicalure-2 or DL2, respectively. Both pheromones are equally attractive to both sexes of the beetle in the field and the laboratory resulting in local accumulations of R. domonica on food hosts, most importantly on stored cereals (Bashir et al., 2001; Edde et al., 2005). Annual post-harvest pest losses world over have been estimated at 10%. Weight losses (dry matter loss) in the range of 0.5-17% in cereals and up to 50% in pulses have been reported (Pantenius, 1988; Rees, 2004). In Nigeria, the loss of grains during storage due to storage insect pests has long been a serious problem to the farmers. Inputs in the form of human power and finances invested in the production of the crop are wasted. Insect contaminants such as excreta (uric acid) exuviate (cast skins) and dead bodies, webbing and secretions in food commodities pose a quality-control problem for food industries. Processing and end-use qualities of food commodities are also affected by insect infestation, as are cash value and marketability of products (Umoeteok et al., 2004).

Current pest management programs for R. dominica as recommended by the Nigerian Ministry of Agriculture and Stored product agencies specify sanitation of empty storage facilities and the use of residual surface treatment, insecticide seed treatments, grain temperature management, routine insect monitoring using grain probes and fumigation when an insect infestation develops (Umoeteok et al., 2004). Methyl bromide and aluminium phosphide are the most common fumigants extensively used all over the world, particularly in developing countries as grain preservatives in larger storage containers. However, some reports have appeared in the literature in which serious toxic effects of these substances to lungs, heart and blood vessels causing pulmonary oedema, shock and arrhythmias have been reported (Singh et al., 1991; Khosla et al., 1992; Abder-Rahman, 1999). Thus, it is highly imperative to look for cheap, less toxic and environmentally friendly natural products for reducing R. dominica damage in storage. Plants, plant parts or extracts with repellent or toxic properties can be used to protect stored products against pest attack (Adler et al., 2000; Boeke et al., 2004).

The objective of this study was to investigate the repellent properties of West African black pepper, Piper guineense Thonn and Schum (Piperaceae) and African nutmeg, Monodora myristica Dunal (Annonaceae) against R. dominica using a four-arm airflow olfactometer in the laboratory. These plants were selected on the basis of their ethnomedical studies and endemicity as their seeds are used in the traditional African medicine for the treatment of headache, constipation, rheumatism, fever, diarrhoea, sores and guinea worm infections. The ripe fresh or dried fruits of these plants are sold in most markets in Nigeria as a spice use for flavouring soups and sauces (Oyedeji et al., 2005; Adewoyin et al., 2006).

MATERIALS AND METHODS

Insect Culture
R. dominica was obtained from stock culture maintained by Central Science Laboratory, Sand Hutton, York, United Kingdom and reared on winter wheat “conqueror” variety seeds in a Constant Temperature and Humidity (CTH) room running at 25°C, 65% relative humidity on a 12:12 DL photoperiod. Fifty pairs of adult R. dominica sexed following the methods of Ghorpade and Thyagarajan (1980) were introduced into 300 g wheat seeds in bell jars. The adults were allowed to feed on wheat grains in the bell jars for 12 days (optimum oviposition time) after which they were removed and discarded. A sieve size of 2 mm, (Endecotts Ltd., England) was used to sieve out the emerged insects daily and records were kept of their sexes and dates of emergence. Beetles whose responses were to be tested in the four-arm airflow olfactometer were kept singly for 6 days and then starved for 24 h before being used for the bioassays.

Plant Material Collection and Preservation
Two plant materials namely; Piper guineense and Monodora myristica were obtained from fields around Akamkpa (situated between latitude 5°00’ and 5°15’ North and longitude 8°04’ and 8°25’ East) in southern Nigeria in December 2006 and identified at the department of Crop Science, University of Calabar, Nigeria. The matured seeds of these plants were dried in the shade for 3 days before transportation.

Bioassays
The four-arm airflow olfactometer was obtained from Rothamsted Research (Harpenden, Hertfordshire, England). It consisted of a four-pointed star-shaped exposure chamber was milled into a circular transparent plastic plate measuring 12x12x1.2 cm, with a hole (3 mm diameter) drilled into the walls at each of the four cardinal points. Another plastic plate (10.2x10.2x0.6 cm) served as the floor and another transparent plastic plate of the same size but with a hole (4 mm diameter) in its centre, served as a cover. Since R. dominica cannot walk on smooth glass surfaces a sheet of Springfield filter paper 125 mm (Springfield Mill, Maidstone, Kent, England) was used as a floor covering. The olfactometer side arms made of socket glass were inserted through the holes of the chamber walls. The air stream through the olfactometer was supplied by the Air entrainment system (KNF Neuberger, Germany) through Teflon tubing measuring 3.2x1.5 mm (Camlab Ltd., UK). Immediately after the pump, the air was divided through 2 carbon rods to clean and dry it. From each carbon rod, the air stream was then further divided and pushed through two flow meters (GPE Ltd., Leighton Buzzard, UK) to give a total of four airflows going into the behaviour chambers at the rate of 200 mL min-1. Each air stream then passed through a glass side arm, which contained either, the odour/volatile source or clean filter paper, which served as a control. The air was pulled from the chamber through the central hole in the cover plastic plate. The different odour sources used to compare the responses of naïve adult male and female R. dominica were; (1) host volatiles emanating from 30 g of whole, sound, grains of white maize or winter wheat seeds “conqueror” variety alone, (2) non-host volatile odours from 30 g partially crushed P. guineense or M. myristica seeds alone, (3) incorporation of 10% (w/w) of each non-host + host plant volatiles combination. Single choice repellent and attraction bioassays consisting of P. guineense and M. myristica as non-host and White maize and winter wheat grains as host plant volatiles listed above were conducted in the CTH room. The olfactometer was coded as five areas: one square shaped central area and four rectangular areas corresponding to the four arms of the olfactometer, each area was marked with a number between 1 and 5. For these bioassays, the arm with the test odour(s) was given number 1; the 3 controls numbered 2, 3 and 4, respectively, while the central arena was given number 5. 30 g partially crushed seeds of the test material was weighed and placed in arm number 1 while the other 3 arms contained clean filter papers and served as controls. Each beetle was observed for ten min using a stopwatch and each bioassay was replicated 10 times. During each replicate, a fresh insect and olfactometer were used, while odour samples were replaced after every 2 replications. All experiments were conducted between 9.00 am and 12.00 pm in the CTH room. After starting the experiment by the release of the beetle into the centre of the olfactometer, the insect was followed visually and considered to have entered a given field when its entire thorax crossed the zone boundary. A computer programme for collecting and analysing behavioural data with the four-armed olfactometer (commonly referred to as OLFA programme) developed by Francesco Nazzi (33100 Udine, Italy) was used to obtain data. The data recorded includes the time spent by the insect in the different areas of the olfactometer and the number of entries into each area or odour zone.

Statistical Analysis
For statistical analysis the software package MINITAB 14 was used. A pair-wise t-test was used to test for significant differences between the treated arm and the mean of the control arms. The time spent and numbers of entries (visits) by the beetle into different odour zones of the olfactometer were the parameters chosen for assessment of the difference between plant volatiles and the control.

RESULTS

The results of the repellent plants bioassay showed that all pair wise comparisons of test with control were significantly different (p<0.0001) from the control. The males spent significantly shorter time in the olfactometer arms emitting volatiles of P. guineense seeds (t = 12.97, p<0.0001) and M. myristica (t = 11.75, p<0.0001) than the control arms receiving clean air. The females also preferred control arms to the treated ones for P. guineense (t = 11.6, p<0.0001) spending a mean 3.04 and 0.62 min, respectively. To M. myristica treated arm, females spent 0.59 min and 3.14 in the control (t = 10.47, p<0.0001). For the number of entries made to each arm, the males significantly preferred control arm to P. guineense and made 3.57 and 1.8 visits, respectively (t = 6.38, p<0.0001), while the mean number of visits to M. myristica arm were 1.5 and the control 3.53 (t = 8.28, p<0.0001). The mean number of entries made by females to P. guineense arm were 1.8 and control 3.33 (t = 5.71, p<0.0001) and to M. myristica arm 1.7 and control 3.43, respectively (t = 7.31, p<0.0001) (Table 1).

For the host plants bioassay, the males were significantly more attracted to maize grains (t = 26.58, p<0.0001) and winter wheat grains (t = 22.79, p<0.0001) than the control. Males spent means of 6.2 and 6.3 min, respectively in the maize and winter wheat treated arms compared to control arm with mean time of 1.15 and 1.16 min, respectively. For the females attraction to maize grains was 5.95 min and control 1.23 min (t = 45.64, p<0.0001) and winter wheat seeds 6.2 min and control 1.11 min (t = 32.84, p<0.0001) (Table 2). For the number of entries or visits made to the treated and control arms, the responses of males to maize grains was 4.89 entries while the control arm was 1.52 (t = 11.18, p<0.0001) and to winter wheat seeds 4.2 entries and control 1.77 entries (t = 8.16, p<0.0001). The females responded to maize grains by making a mean number 5.11 entries and control 1.63 entries (t = 12.04, p<0.0001) and to winter wheat 4.4 entries with the control arm receiving 1.67 entries (t = 11.52, p<0.0001) (Table 2).

For the 10% repellent plants and maize seed volatiles bioassay results, the males were significantly repelled by P. guineense (t = 8.9, p<0.001) and M. myristica (t = 5.42, p<0.001) in the mean time spent than the control. The females also showed significant repulsion from P. guineense (t = 7.44, p<0.001) and M. myristica (t = 7.43, p<0.001) compared to control arms (Table 3). For the number of entries made between treated and control arms, the males were significantly repelled from P. guineense (t = 3.02, p<0.014) but not repelled by M. myristica (t = 1.91, p<0.089) than control arms. Females were significantly repelled by P. guineense (t = 2.49, p<0.034) and M. myristica (t = 3.67, p<0.005) treated arms than control arms (Table 3).

When 10% repellent plant volatiles were combined with winter wheat seeds, males were significantly repelled by P. guineense (t = 10.03, p<0.0001) and M. myristica (t = 10.86, p<0.0001) in the mean time spent than controls. Females were also repelled by P. guineense (t = 10.14, p<0.0001) and M. myristica (t = 11.76, p<0.0001) in the mean time spent than control arms (Table 4).

Table 1: Mean time spent in the test or average of three control arms out of 10 min and mean number of entries made by R. dominica adults in response to 30 g P. guineense or 30 g M. myristica seeds in the airflow olfactometer

Table 2: Mean time spent in the test or average of three control arms out of 10 min and mean number of entries made by R. dominica adults in response to 30 g Winter wheat or 30 g maize grains in the airflow olfactometer

Table 3: Mean time spent in the test or average of three control arms out of 10 min and the mean number of entries made by R. dominica adults in response to 30 g Maize + 10% M. myristica or 30 g maize + 10% P. guineense

Table 4: Mean time spent in the test or average of three control arms out of 10 min and the mean number of entries made by R. dominica adults in response to 30 g wheat + 10% M. myristica or 30 g winter wheat + 30 g P. guineense

For the number of entries, the males made significantly less entries to P. guineense (t = 4.20, p<0.002) and M. myristica (t = 4.40, p<0.002), respectively. Females significantly frequented control arms than P. guineense (t = 4.74, p<0.001) and M. myristica (t = 5.13, p<0.001) as well (Table 4).

DISCUSSION

Based on the results of this study, adult R. dominica demonstrated clear orientation choices between the volatiles generated by host and non-host plants and a combination of volatiles emitted by both. Adult R. dominica that were given the choice between control and P. guineense or M. myristica seeds in the four arm airflow olfactometer significantly preferred the control arms. This suggests that R. dominica are able to detect these repellent plants through olfaction and avoid them when given the choice. This could explain at least in part, how the application of P. guineense and M. myristica protects grain from insect infestation in storage. These repellent plants may contain certain active volatile component that elicits antifeedant behaviour by the visiting insect. The compositions of the volatile oil from the seeds (berries) of these plants have been investigated: the major components of P. guineense seeds are dominated by monoterpenoids and moderate sesquiterpenoids including β-Pinene, β-Caryophyllene, Bicyclogermacrene, α-Pinene, Germacrene, δ-3-Carene, E-α-Bisabolene, α-Cubebene, Sabinene, Camphor, α-Phellandrene, β-Phellandrene, χ-Muurolene, Z-Nerolidol, Z-β-Ocimene, Myrcene, Ishwarane, Myristicin, Dillapiole, Elemicin, Limonene and Camphene (Salgueiro et al., 1998; Oyedeji et al., 2005). M. myristica essential oil components include α-Thuyene, α-Pinene, Myrcene, Limonene, α-Phellandrene, p-Cymene, Isopugegol, Aromandendrene, α-Terpineol, Carvacrol, Thymol and cis-Sabinol (Cimanga et al., 2002; Tatsadjieu et al., 2003). These essential oil components could be responsible for the repellent activity of P. guineense and M. myristica seeds against R. dominica in the airflow olfactometer. Similar findings have been reported by Oparaeke et al. (2006) that aqueous mixtures of P. guineense with garlic (Allium sativum) bulb at 10:10 and 20:10% w/v significantly reduced the population of the cowpea flower thrips, Megalurothrips sjostedti and increased the pod density compared to cypermethrin plus dimethoate which was the synthetic check. Umeh and Ivbijaro (1999) reported that the crude seed oil of P. guineense at 10% concentration significantly reduced damage by the termites Macrotermes bellicosus and M. subhyalinus in maize plots and increased yield. M. myristica has been reported to exhibit antibacterial properties against Bacillus subtilis, Citrobacter sp., Escherichia coli, Proteus vulgaris, Salmonella typhimurium and Shigella flexneri (Cimanga et al., 2002) and antifungal activity against Aspergillus flavus (Tatsadjieu et al., 2003). On the bioactivity of botanicals against R. dominica, Hassanali et al. (1997) reported that the bioactivity of materials derived from the leaves and succulent stems of Ocimum kenyense evoked high repellency against S. zeamais, moderate repellency against R. dominica and low repellency against Sitotroga cerealella in the laboratory. Also Belmain et al. (2005) reported that Securidaca longepedunculata (Polygalaceae) root powder, its methanol extract and the main volatile component, methyl salicylate, exhibited repellent and toxic properties to stored products insect pests. Methyl salicylate vapour also showed fumigant effect against R. dominica, S. zeamais and Prostephanus truncatus. The fact that insect response to particular plant volatiles can be markedly influenced by the concentration of that volatile is common in chemical ecology (Chhabra et al., 1999; Belmain et al., 2005). Only recently, Ukeh et al. (2007) reported that plantain inflorescence ash and crude neem products were effective in the prevention of insect pests’ colonization of Solanum melongena in the field, suggesting that plant allelochemicals exert a wide range of effects on insects as repellents, deterrents and antifeedants.

Maize and winter wheat kernels were found attractive to R. dominica in the single choice olfactometer bioassay. Pike et al. (1994) identified the main volatile compound of maize seeds as hexanoic acid, nonanoic acid, nonanal, decanal, 2-phenylethanol and vanillin. The study showed that both male and females spent more time in the olfactometer arms emitting maize and wheat volatiles and could mean that the enhancement of attraction could be expected with other cereals. It might be thought that the attraction of the beetle to host volatiles was in response of both sexes to their proximity to a food source and an increased pheromone output by the males. These results confirmed the reports of Bashir et al. (2001) on the behavioural responses of R. dominica to blends of host volatiles and male-produced aggregation pheromone in the four-arm airflow olfactometer. They concluded that males spent significantly more time than females in the zone with only maize volatiles and females spent significantly more time in the higher maize volatiles zone. This could suggest that males are more likely to attract mates to a food source resulting to the formation of leks. In this study, no significant differences were observed between the sexes in their response to maize or winter wheat volatiles. Ako et al. (2003) also reported no sexual behavioural differences when adult male and female S. zeamais were presented with maize seeds infested with Fusarium verticillioides and healthy maize kernels in a four-arm airflow olfactometer. Similarly, no sexual behavioural differences were reported between both sexes of another Coleopteran, Scyphophorus acupunctatus to their host plant Agave tequilana volatiles although they were attractive to the host volatiles in the Y-tube olfactometer bioassays (Altuzar et al., 2007).

These studies have reported the viability of the use of semiochemicals (behaviour modifying chemicals) for the monitoring and prevention of R. dominica in stored products. Repellents have the potential for the exclusion of stored product pests from grain and have been used to prevent insect feeding and oviposition. They represent an important part of the integrated pest management strategies in Africa because they are locally available, less expensive and safe to the environment.

REFERENCES
Abder-Rahman, H., 1999. Effect of aluminium phosphide on blood glucose level. Vet. Hum. Toxicol., 41: 31-32.
Direct Link  |  

Adewoyin, F.B., A.B. Odaibo and C.O. Adewunmi, 2006. Mosquito repellent activity of Piper guineense and Xylopia aethiopica fruits oils on Aedes aegypti. Afr. J. Trad. Compl. Alt. Med., 3: 79-83.
Direct Link  |  

Adler, C., P. Ojimelukwe and T.A. Leon, 2000. Utilisation of phytochemicals against stored product insects. Integ. Prot. Stored Prod., 23: 169-175.

Altuzar, A., E.A. Malo, H. Gonzalez-Hernandez and J.C. Rojas, 2007. Electrophysiological and behavioural responses of Scyphophorus acupunctatus (Coleoptera: Curculionidae) to Agave tequilana volatiles. J. Applied Entomol., 113: 121-127.
Direct Link  |  

Arthur, F.A., D.W. Hagstrum, P.W. Flinn, C.R. Reed and T.W. Phillips, 2006. Insect populations in grain residues associated with commercial Kansas's grain elevators. J. Stored Prod. Res., 42: 226-239.
Direct Link  |  

Bashir, T., L.A. Birkinshaw, D.R. Hall and R.J. Hodges, 2001. Host odours enhance the responses of adult Rhyzopertha dominica to maleā€produced aggregation pheromone. Entomol. Exp. Applied, 101: 273-280.
CrossRef  |  Direct Link  |  

Bekele, A.J., D. Obeng-Oforis and A. Hassanali, 1997. Evaluation of Ocimum kenyense (Ayobangira) as source of repellents, toxicants and protectants in storage against three major stored product insect pests. J. Applied Entomol., 121: 169-173.
Direct Link  |  

Belmain, S.R., T.K. Jayasekara, P.C. Stevenson and D.R. Hall, 2005. Effect of volatile constituents from Securidaca longepedunculata on insect pests of stored grain. J. Chem. Ecol., 31: 303-313.
Direct Link  |  

Boeke, S.J., I.R. Baumgart, J.J.A. van Loon, A. van Huis, M. Dicke and D.K. Kossou, 2004. Toxicity and repellence of African plants traditionally used for the protection of stored cowpea against Callosobruchus maculatus. J. Stored Prod. Res., 40: 423-438.
Direct Link  |  

Cimanga, K., K. Kambu, L. Tona, S. Apers and T. De-Bruyne et al., 2002. Correlation between chemical composition and antibacterial activity of essential oils of some aromatic medicinal plants growing in the Democratic Republic of Congo. J. Ethnopharmacol., 79: 213-220.
PubMed  |  Direct Link  |  

Cogburn, M.W., 1988. Detection, distributional and seasonal abundance of Sitotroga cerealella and Rhyzopertha dominica as indicated by pheromone-baited adhesive traps. Proceedings of the XVIII International Congress of Entomology, Jul. 3-9, University of British Columbia, Vancouver, Canada.

Edde, P.A., T.W. Phillips and M.D. Toews, 2005. Responses of Rhyzopertha dominica (Coleoptera: Bostrichidae) to its aggregation pheromones as influence by trap design, trap height and habitat. Environ. Entomol., 34: 1549-1557.
Direct Link  |  

Edde, P.A., T.W. Phillips, J.B. Robertson and J.W. Dillwith, 2007. Pheromone output by Rhyzopertha dominica (Coleoptera: Bostrichidae), as affected by host plant and beetle size. Ann. Entomol. Soc. Am., 100: 83-90.
Direct Link  |  

Ghorpade, K.D. and K.S. Thyagarajan, 1980. A reliable character for sexing live or dead Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae). J. Stored Prod. Res., 16: 151-153.
CrossRef  |  Direct Link  |  

Hagstrum, D.W., 2001. Immigration of insects into bins storing newly harvested wheat on 12 Kansas farms. J. Stored Prod. Res., 37: 221-229.
Direct Link  |  

Haines, C.P., 1991. Insects and Arachnids of Tropical Stored Products: Their Biology and Identification (A Training Manual). 1st Edn., Natural Resources Institute, Chatham, UK., pp: 246.

Howe, R.W., 1950. The development of Rhyzopertha dominica (Coleoptera: Bostrichidae) under constant conditions. Entomol. Mont. Mag., 86: 1-5.

Kholsa, S.N., P. Handa and P. Kholsa, 1992. Aluminium phosphide poisoning. Trop. Doc., 22: 155-157.

Khorramshahi, A. and W.E. Burkholder, 1981. Behaviour of the lesser grain borer Rhyzopertha dominica (Coleoptera: Bostrichidae); Male-produced aggregation pheromones attracts both sexes. J. Chem. Ecol., 7: 33-38.

Landolt, P.J., 1997. Sex attractant and aggregation pheromones of male phytophagous insects. Am. Entomol., 43: 12-22.
CrossRef  |  Direct Link  |  

Law-Ogbomo, K.E. and D.A. Enobakhare, 2006. Efficacy of rubber seed oil, palm oil and palm kernel oil as grain protectants against Sitophilus zeamais (Mots.) (Coleoptera: Curculionidae) in three maize varieties. J. Entomol., 3: 40-47.
CrossRef  |  Direct Link  |  

Martins, A.P., L. Salgueiro, R. Vila, F. Tomi and S. Canigueral et al., 1998. Essential oils from four Piper species. Phytochemistry, 49: 2019-2023.
CrossRef  |  Direct Link  |  

Meikle, W.G., R.H. Markham, C. Nansen, N. Hoist, P. Degbey, K. Azoma and S. Korie, 2002. Pest management in traditional maize stores in West Africa: a farmers perspective. J. Econ. Entomol., 95: 1079-1088.
Direct Link  |  

Ndungu, M.W., S.C. Chhabra and W. Lwande, 1999. Cleome hirta essential oil as livestock tick (Rhipicephalus appendiculatus) and maize weevil (Sitophilus zeamais) repellent. Fitoterapia, 70: 514-516.
CrossRef  |  Direct Link  |  

Oparaeke, A.M., M.C. Dike and C.I. Amatobi, 2006. Field activity of three mixture levels of plant extracts formulations for the management of post-flowering insect pests of cowpea, Vigna unguiculata (L.) bWalp- the flower thrips, Megaluthrips sjostedti (Trybom). J. Sust. Agric., 28: 45-54.
Direct Link  |  

Oyedeji, O.A., B.A. Adeniji, O. Ajayi and W.A. Konig, 2005. Essential oil composition of Piper guineense and its antimicrobial activity: Another chemotype from Nigeria. Phytother. Res., 19: 362-364.
Direct Link  |  

Panthenius, C.U., 1988. Storage losses in traditional maize granaries in Togo. Ins. Sci. Applic., 9: 725-735.

Pike, V., J.L. Smith, R.D. White and D.R. Hall, 1994. Studies of Responses of Stored-Products Pests, Prostephanus truncatus (Horn) and Sitophilus zeamais (Motsch.), to Food Volatiles. In: Highley, E., E.J. Wright, H.J. Banks and B.R. Champ (Eds.). Proceedings of the 6th International Working Conference on Stored-Product Protection, CAB International, Wallingford, UK.

Rajendran, S., 2005. Detection of insect infestation in stored foods. Progr. Opt., 49: 163-232.
Direct Link  |  

Razkin, J., P. Gil and A. Gonzalez, 1996. Stereoselective synthesis of dominicalure 1 and 2: Components of aggregation pheromone from male lesser grain borer, Rhyzopertha dominica (F.). J. Chem. Ecol., 22: 673-680.
Direct Link  |  

Rees, D., 2004. Insects of Stored Products. CSIRO Publishing, Australia, ISBN-13: 9780643102637, Pages: 192.

Sculthess, F., M. Ako, M.Y.D. Gumedzoe and K.F. Cardwell, 2003. The effect of Fusarium verticillioides on oviposition behaviour and bionomics of lepidopteran and coleopteran pests attacking the stem and cobs of maize in West African. Entomol. Exp. Applic., 106: 201-210.

Singh, R.B., R.G. Singh and U. Singh, 1991. Hypermagnesemia following aluminium phosphide poisoning. Int. J. Clin. Pharm., 29: 82-85.
Direct Link  |  

Tatsadjieu, L.N., J.J. Essia Ngang, M.B. Ngassoum and F.X. Etoa, 2003. Antibacterial and antifungal activity of Xylopia aethiopica, Monodora myristica, Zanthoxylum xanthoxyloides and Zanthoxylum leprieurii from Cameroon. Fitoterapia, 74: 469-472.
Direct Link  |  

Ukeh, D.A., S.B.A. Umoetok, P. Iwejuo and S.O. Emosairue, 2007. Effects of plantain inflorescence ash and neem seed extracts on the yield and insect pests of eggplant (Solanum melongena L.) in Calabar, Nigeria. Res. J. Agron., 1: 88-93.
Direct Link  |  

Umeh, V.C. and M.F.I. Ivbijaro, 1999. Effects of termite damage to maize of seed extracts of Azadirachta indica and Piper guineense in farmers fields. J. Agric. Sci. Camb., 133: 403-407.
Direct Link  |  

Umoeteok, S.B.A., E.E. Oku and D.A. Ukeh, 2004. Reduction of damage caused to stored cowpea (Vigna unguiculata L.) seeds by the bean Bruchids (Callosobruchus maculatus F.) using plant products. J. Food Technol., 2: 192-194.
Direct Link  |  

Williams, H.J., R.M. Silverstein, W.E. Burkholder and A. Khorramshali, 1981. Dominicalure 1 and 2: Components of aggregation pheromone from male lesser grain borer Rhyzopertha dominica (F.). J. Chem. Ecol., 7: 759-780.

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