Storage Insect Research Articles

Occurrence of Stored Grain Insect Pests in Traditional Underground Pit Grain Storages of Eastern Ethiopia

Grain samples were collected from 179 on-farm traditional underground pit stores found in agro pastoralist villages. The samples were collected from four district namely Babille, Gurusm, Jigjiga and Awbarre districts of Ethiopian Somali provenance. The study was conducted to assess the occurrence and damage related to storage insect pests in traditional grain pit stores. Data on relative abundance, insect grain damage and germination percentage for each district were summarized and subjected to descriptive statistics analysis and mean and standard deviation were performed. According to the result, all assessed grain stores exhibited with significant infestation with storage insect pests. Over all finding indicted that maize weevil ( S zeamais ), angoumois grain moth ( S cerealella ) with mean relative abundance of 41.25 and 28.52% respectively others including flour beetle ( T castenum ), flat grain beetles ( C ferugineus ) and Saw-toothed grain beetle ( O surinamensis ) were also commonly recorded in all assessed districts. Maximum grain damage in sorghum was recorded from Awbarre district 29.27%. The highest grain damage in maize was recorded in Babile (33.88%), Gursum 32.47% and Jigjiga 30.86%. Sorghum and maize grain stored for at least 8-9 month showed mean germination percentage of 72.81% and 66.96% respectively. Keywords: Stored grain insect pests underground pit storage system

Fumigant toxicity of essential oils against four stored grain insect pests in stored paddy seeds

A laboratory experiment was conducted to find out the fumigant toxicity of essential oils of Murraya koenigii, Citrus reticulata, Curcuma longa, and Pinus. roxburghii against Sitophilus oryzae, Rhyzopertha dominica, Tribolium castaneum and Sitotroga cerealella for long term protection of paddy seeds in plastic jars. Most of the essential oils either alone or in combinations protect the paddy seeds against test insects up to one year at different concentrations as compare to untreated control. The tested essential oils also prevent the weight losses due to insect infestations. The quality of paddy seeds and germination percentage were not affected by these essential oils.

Atraktivnost mirisa infestirane i neinfestirane pšenice u zrnu i prekrupe za skladišne tvrdokrilce

Using a two-way olfactometer, the effects of the whole wheat grains and coarse wheat meal odors on the primary Sitophilus granarius (L.), S. oryzae (L.) and S. zeamais (Motch.) and secondary Tribolium castaneum (Herbst) and T. confusum (Du Val) stored-product pests behavior were examined. Whole wheat grains and coarse wheat meal were used in uninfested and infested form. Whole wheat grains were infested with S. oryzae adults and coarse wheat meal with T. castaneum adults. The odors of infested wheat grains depending on the insect species were 1.9 to 3 times more attractive than the uninfested wheat grains odors, except for the T. castaneum for whome the odors of infested and uninfested grains were equally attractive (p = 0.641). The greatest difference in the attractiveness of the infested and uninfested wheat grains odors was found for T. confusum (3 times longer in the arm with the odors of infested grain), and the smallest for S. granarius (1.9 times). We found that all primary and secondary stored-product pests, depending on the species, were 1.4 - 2.4 times more attracted to the odors of infested compared to the odors of uninfested wheat meal. The greatest difference in the atraction of infested and uninfested coarse wheat meal odors was recorded for the T. confusum, whose adults were 2.4 times longer in the arm with the odors of infested coarse wheat meal than in the arm with odors of uninfested wheat meal, while the smallest difference (1.4 times) was recorded for S. oryzae. The results of this study give a significant contribution to a better understanding of the storage insects behavior, which could be used in the design of new methods of monitoring of their presence in stored products.

Suppressing aflatoxin biosynthesis is not a breakthrough if not useful.

Liver-affecting, carcinogenic aflatoxins produced by Aspergillus spp. are a major problem, especially in the humid developing world where storage conditions are often optimal for the fungi. Peanuts and maize have been transformed with RNAi constructs targeting Aspergillus flavus polyketide-synthase, an early key enzyme in aflatoxin biosynthesis. Aflatoxin biosynthesis was suppressed in developing immature grain, less so in late maturing grain, and it is doubtful that the technology will be effective in near dry mature grain. The infected grain was still mouldy. As Aspergillus that infects grain preharvest can continue to grow and produce aflatoxin in poorly stored grain, and grain storage insects vector further infections, this technology seems to have little potential utility in the humid tropics. The biotechnological approaches of RNAi directly targeting Aspergillus, coupled with transgenic insecticidal proteins should be far more effective. These biotechnological approaches can be used in tandem with the RNAi against polyketide-synthase, as well as with irradiation, biocontrol and better grain drying and hermetic dry storage in a controlled atmosphere. © 2017 Society of Chemical Industry.

Effect of the Establishment of Cigarette Beetle Population on the Quality of Stored Cnidium Rhizome and Angelica Radix at Room Temperature

Background: The current regulations regarding the storage of medicinal herbs do not define the storage temperature; instead, but the only requirement is that the plastic bags used for storing the medicinal herbs should be tightly sealed during storage. The practice of storing medicinal herbs at room temperature (28℃), causes many problems, including growth of insect pests on the stored medicinal herbs. Thus, it is necessary to understand the effect of insect pests on the quality of medicinal herbs stored at room temperature (28℃) for the improving the relevant regulations.Methods and Results: Cnidium rhizome and Angelica radix were infested with Lasioderma serricorne F. adults and incubated at 28℃ for 2.5 and 5 months. The population of L. serricorne was established rapidly, and left many holes, cadavers, and feces on the stored medicinal herbs, thereby greatly damaging the product appearance and hygiene. In addition, active ingredients of the medicinal herbs were significantly decreased, probably reducing their medicinal quality as well.Conclusions: These results indicate that the current regulations are not sufficient to prevent the establishment of storage insect pests and guarantee the quality and hygiene of stored medicinal herbs. Therefore, it is necessary to devise proper storage protocols and upgrade the current relevant regulations to maintain the quality of medicinal herbs during storage.

Survey on Storage Insect Pest, Methods of Storage and Management Measures on Sorghum Grain around Sub Zoba Hamelmalo, Eritrea

Survey was intended to study the storage insect pests in sorghum around the sub-zoba Hamelmalo. Though this crop is one of the most stable field crops in Eritrea, it is severely infested by many storage insect pests. Therefore, the survey was conducted to address the challenges with storage insect pests with the aim of identifying the storage insect pests of sorghum grains, storage methods of the subsistence farmers and its management practices used by the farmers. The survey was carried out in sub-zoba Hamelmalo by using open ended questionnaires. Five administrative villages were randomly selected and from each village eleven farmers were selected at random for interview and sample collections. Five hundred gram of sorghum grains were collected and checked for pest occurrence and emergence in the laboratory. Sitophilus oryzae, Sitotroga cerealella and Sitophilus granaries were recognized as major storage insect pests in the representative administrative villages. The study discovered that the weight losses due to the storage insect pests range from 0.089% to 1.82% in sub-zoba Hamelmalo. The interview showed farmers in the sub-zoba used different management practices including ash mixing with grain, sun drying, cleaning, plant materials and insecticides to protect the grain from storage insect pests. In addition to that it is indicated that the most of the growers of the sampled villages used polyethene (meshemae) and guffet (traditional storage material) to store their produce.

A review study on botanical pesticides for the management of stored grain insect pests

Sheath Blight, Disease, Rice, Distribution, Systems, Management.

Chemical variation and insecticidal activity of Lippia javanica (Burm. f.) Spreng essential oil against Sitophilus zeamais Motschulsky

Lippia javanica (Burm. f.) Spreng is used commercially as an herbal tea and medicinal plant in sub-Saharan Africa. Here we investigated the chemical variation and pesticidal potential of L. javanica essential oils against a major stored product pest, Sitophilus zeamais Motschulsky. We identified two morphologically distinct varieties of L. javanica growing at different locations in Malawi. Perillaldehyde was the major constituent in oil of L. javanica var. javanica while myrcenone (ipsdienone) was the major compound in oils of L. javanica var. whytei. Myrcene, linalool, carvone, β-caryophyllene and germacrene D were identified as the other most significant components in oils from both varieties. The yields of oil and the chemical composition also varied significantly with time of harvest during the season in both cases. In contact toxicity tests against S. zeamais, oils from both varieties were active. However, whereas perillaldehyde, linalool and carvone, components of the oil of L. javanica var. javanica, were all toxic against adult S. zeamais, myrcenone, the main component of oil from L. javanica var. whytei, was not. The oil from L. javanica var. javanica also showed some fumigant toxicity against S. zeamais. The high efficacy of L. javanica oil against S. zeamais suggests it is suitable to be used as a botanical insecticide to control S. zeamais in stored maize. However, further research is required to optimise and standardise the variety and harvest time to be recommended and to evaluate its activity against S. zeamais and other storage insect pests under farm conditions before it can be adopted by farmers more widely.

Eco-friendly management of Sitophilus oryzae and Rhyzoper thadominica in stored wheat at Pantnagar, Uttarakhand

he laboratory experiments were conducted to study the efficacy of some indigenous products such as plant products (chopped neem leaves ajwain seed powder, garlic capsules, saw dust), animal derivedproducts ( cow dung cake powder, cow urine) and inert materials ( ash powder, sand, talcum powder, salt) @ 2g/100g of wheat grains against rice weevil, Sitophilus oryzae (Linn.) and lesser grain borer, Rhyzoper thadominica (Fab.) on stored wheat by undertaking various parameters viz., percent adult emergence, percent seed damage, per cent weight loss and per cent germination after six months of storage during April to October 2015. After 180 days of treatments, the minimum number of adults weevils of S. oryzae( 4.00, 6.00,7.67, 9.00, 9.67 and 10.33) were emerged in wheat grains treated with ash powder, sand, cow dung powder, talcum powder, ajwain seed powder and neem leaf powder, respectively with minimum grain damage (7.33 %, 8.67 %,11.67 % and 12.00 %) was observed on ash powder, sand, ajwain seed powder and talcum powder, respectively, whereas minimum weight loss (2.67 %, 3.67 %, 5.67 % and 6.67 %) was recorded on ash powder, sand, cow dung powder, talcum powder and ajwain seed powder, respectively. Similarly, the minimum number of adult beetles of R. dominica were emerged (2.00,2.33, 6.67,7.00 and 8.33) in ash power, sand, talcum powder, cow dung cake powder and ajwain seed powder, respectively with minimum grain damage (4.00 %,8.00 %. 8.67 % and 12.67 % and weight loss (1.33 %, 4.00 %, 7.33 % and 11.67 %) in sand, ash powder, talcum powder and cow dung cake treated wheat grains, respectively. It has been clearly observed that seed germination was not affected adversely in any treatment during six months of storage. The present study clearly revealed that these naturally occurring indigenous products could be used to manage the storage insect pests in wheat.

Chemical composition and insecticidal properties of essential oil from aerial parts of <i>Mosla soochowensis</i> against two grain storage insects

Purpose: To determine the insecticidal properties of essential oil from Mosla soochowensis aerial parts against two insect pests, Sitophilus zeamais and Tribolium castaneum.Methods: Hydro-distillation of M. soochowensis was used to extract the essential oil. Gas chromatography/mass spectrometry (GC/MS) analysis was performed, and the contact (topical application) and fumigant toxicity (sealed space) of the essential oil were evaluated.Results: Thirty-nine chemical compounds were identified by GC-MS analysis of M. soochowensis essential oil. The major components are β-caryophyllene (12.82 %), spatulenol (6.34 %), β-eudesmol (6.26 %), carvone (6.12 %), α-thujone (5.12 %), γ-eudesmol (4.86 %), α-cedrol (4.23 %), and α- caryophyllene (4.04 %). The plant essential oil exerted contact toxicity against adults of S. zeamais and T. castaneum (median lethal concentration (LC50), 25.45 and 10.23 μg/adult, respectively). Moreover, the essential oil exhibited pronounced fumigant toxicity towards adults of both species (LC50 12.19 and 10.26 mg/L air, respectively).Conclusion: These results show that M. soochowensis essential oil can be used in development of safer and more natural and effective fumigants/insecticides for stored products.Keywords: Mosla soochowensis, Contact toxicity, Sitophilus zeamais, Fumigant, Insecticide, Essential oil, Tribolium castaneum

Genotypic variation for maize weevil resistance in eastern and southern Africa maize inbred lines

The maize weevil ( Sitophilus zeamais Motschulsky) is the most destructive storage insect pest of maize ( Zea mays L.) worldwide, especially among susceptible varieties. Breeding for grain resistance against the weevil is a major component of an integrated pest management strategy in maize production. The objective of this study was to identify diverse sources of weevil resistance for introgression in breeding programmes. A total of 180 inbred lines from three geographical areas were screened for maize weevil resistance. Screening was executed by infesting 50 g of maize grain with 32 newly emerged adult weevils, placed in 250 cm 3 glass jars in a “no-choice” laboratory test. The grain susceptibility parameters used were F 1 weevil progeny emergence, percent grain damage, median development period, Dobie’s index of susceptibility, and parental weevil mortality. New sources of weevil resistance for maize breeding were identified. Eight inbred lines were consistently resistant and, therefore, selected as potential donors for weevil resistance in the maize improvement programmes. There was significant genetic variation, and high levels of heritability (89 – 96%) for weevil resistance that suggested high potential for germplasm improvement through selection. No significant association was observed between maize weevil resistance and grain yield, suggesting that breeding for maize weevil resistance can be achieved without compromising grain yield. Keywords: Sitophilus zeamais , weevil resistance, Zea mays

Use of entomopathogenic fungi for the control of stored-product insects: can fungi protect durable commodities?

Entomopathogenic fungi are considered promising microbial control agents for the control of post-harvest insects, and their evaluation for this purpose has lately attracted a significant amount of research. They are naturally occurring, environmentally safe organisms that infect insects by contact. Insect fungal pathogens have a broad spectrum of hosts, can be mass-produced easily, rapidly and economically and can be applied with the same technical means as conventional contact insecticides. In this context, the most studied fungal species for the control of stored-product insect species are Beauveria bassiana and Metarhizium anisopliae. Both fungal species have a wide host range and have been tested against most of the major stored-product insect pests. The effect of biotic and abiotic factors on the virulence and success of entomopathogenic fungi in storage insect control, as well as the combined application of these agents with other pest control technologies, is reviewed here. Temperature and relative humidity influence the efficacy of entomopathogenic fungi, often with variable results, whereas the combined use of entomopathogenic fungi with diatomaceous earth in many cases has a synergistic or additive effect. Alternative methods of entomopathogenic fungi application, based on the lure-and-kill approach, are proposed, and future challenges for the use of entomopathogenic fungi against stored-product insects are highlighted.

Maize storage insects (Sitophilus zeamais and Prostephanus truncatus) prefer to feed on smaller maize grains and grains with color, especially green

Maize is the major food staple in Eastern and Southern Africa, and since production is seasonal, on-farm storage is practiced by farmers. Because stored maize is susceptible to pests, improved storage methods are being developed which need to be evaluated for their effectiveness in reducing losses. The standard count and weigh method (CWM) assumes storage insects attack grains of different sizes in equal measure, although this has not been tested. This study therefore analyzed storage insects’ feeding preferences for maize grains of different sizes. Maize grain was sieved and split into four size categories, colored with food dyes, remixed, and distributed into 48 jars, each with about 300 g of grain, artificially infested with maize weevils (Sitophilus zeamais) or larger grain borers (Prostephanus truncatus), 40 insects per jar. After two months, the grains were separated into their size categories (visually, by color), and grain damage and weight loss was estimated with the CWM. Results show that storage insects have a preference for feeding on smaller, rather than larger grains; and on colored rather than uncolored grains. Small-sized and colored grains were more likely to be perforated by insects and suffered more weight loss. This preference, observed for both species, is more pronounced in S. zeamais, who also distinguish between different colors, and prefer green. The size effect is, however, comparatively small and the average weight loss calculated by a size-adjusted formula is not significantly different from that calculated by the standard CWM. However, the resulting differences in weight losses between grains of different sizes are small. Weight loss calculated by weighted CWM, while in principle more accurate, does not in practice lead to significantly different estimates. Therefore, the results do not warrant a change in the conventional CWM for weight loss in stored grain.

Study of traditional fish drying activities at Atrai upazilla of Naogaon district in Bangladesh

The investigation was conducted on traditional fish drying activities of the Atrai upazila under Naogaon district from July 2011 to December 2011. There was only one fish drying point was found in study area. The observed fish drying points are seasonal (from July to December). There are sixteen fish species were identified for drying among study area. Most of the raw fish collect from local market or Atria River. Transportation of raw fish was done by non-mechanized van or by head load of the labour. Price of the raw fish varied according to the species, size and availability. It is observed that September-October peak period for drying. The rate of mixing salt in the study area was found as 1kg salt for 12 kg of raw fish. At normal weather condition drying duration recorded to be varied from 2-5 days depend on the size of the raw fish. Plastic, jute sack and sometimes bamboo baskets were used for packaging purpose. The marketing channel is too small here. It was found that all the dried fish product in study areas, carried to the Sayadpur dry fish wholesale market in Nilphamary district directly by producers. The annual production of dried fish range 6000-8000 Kg. The highest price per kg dried fish was found as 400-550 Tk (Baim) and the lowest was found as 90-120 Tk (Punti, Darkina, Colisa). The cost benefit ratio for fish drying activities of study area was 1:0.671. The dry fish trader faced some problem such as insufficient credit, lack of raw fish insect infestation, storage and marketing facilities. From the present study some recommendations were also formulated to minimize the problem.Asian J. Med. Biol. Res. December 2016, 2(4): 646-655

Studies on Spatial Distribution of Phosphine Resistance in Rice Weevil, Sitophilus Oryzae (L.) (Curculionidae: Coleoptera) Collected from Tamil Nadu

Fumigation with phosphine gas is the most common method of stored grain insect pest control in India. However, heavy and indiscriminate use of phosphine over several years resulted in development of heritable resistance in key stored grain insect pests. No detailed information is available on the current status of phosphine resistance in Sitophilus oryzae (L.) and its spatial distributions in different geographical locations of India. Twenty two samples of S. oryzae collected from various parts of Tamil Nadu were tested through bioassay for determining the level of resistance on the basis of the response of adults to discriminating concentration of 0.04 mg L−1, for 20 h exposure. The bioassay results showed that resistance was common in all the field collected populations of S. oryzae and the level resistance ranged from 21.21 to 93.38%. Of the 22 populations tested, 54.54% showed low resistance, 22.73% were medium and 22.73% exhibited high resistance. The populations from Kumbakonam showed high level resistance (93.38%). The low level resistance was observed in Peelamedu (21.21%) population. Spatial analysis of different geographical distance and % resistance showed a negative correlation with spatial distance and level of resistance (r =-0.083 and simulated p-value = 0.8249) in S., oryzae populations collected from Tamil Nadu.

Common bean (Phaseolus Vulgaris l.) landraces reaction to field and storage insect pests: baseline data for insect resistant and high-yielding common bean variety development

Common bean is a lowland legume crop that contributes for food security and poverty reduction in Ethiopia. A number of constraints are associated with common bean production in Ethiopia including drought, insect pests, diseases, low number of improved variety, storage practices, storage insect pest management and seed systems among others. Therefore, this study was conducted to investigate the interaction of selected common bean landraces against field and storage insect pests. The field experiment was done at Arsi-Negele in the West-Arsi zone at the sub-center of Melkasa Research Centre (mrc) in Oromia Regional State of Ethiopia. Ten common bean landraces and one improved variety (Beshebeshe) were collected from mrc and evaluated under field and storage conditions. The field experiment was designed in a randomized complete block design in three replications, while the storage experiment was designed in a completely randomized design in three replications. Highly significant variations were observed in the tested common bean landraces in terms of field and storage insect pests. The landraces were not consistent in terms of insect pest reaction across the different plant growth stages and in the storage. This study demonstrated the high potential that existed in common bean landraces in terms of insect pest resistance. Hence, the result of this study calls for a strong collaborative work between common bean breeders and entomologists to develop high yielding and insect resistant common bean varieties.

Fumigant toxicity of essential oils against four major storage insect pests

As laboratory experiments were carried out to find the fumigant toxicity of 17 essential oils extracted from locally available plants against four storage insect pests, Sitophilus oryzae, Rhyzopertha dominica, Tribolium castaneum and Callosobruchus Chinensis in wheat and gram. The essential oils from Allium sativum, Artemisia annua, Callistemon citrinus, Chenopodium botrys, Cinnamomum zylanicum, Citrus reticulata, Cuminum cyminum, Foeniculum vulgare, Murraya koenigii, Pinus roxburghii, and Piper nigram were found highly effective against all test insects at 0.2 and 0.4%. The essential oil of Lantana camera, Cinnamomum tamala and Curcuma longa were found highly effective against R. dominica, T. castaneum and C. chinensis at 0.4% concentration.

Survival rate of Plodia interpunctella (Lepidoptera: Pyralidae): On different states of wheat and rye kernels previously infested by beetle pests

The present study was undertaken to determine survival rate of Plodia interpunctella (Hübner, 1813), reared on different mechanical states of Vizija winter wheat cultivar and Raša winter rye cultivar, previously infested with different beetle pests. Wheat was previously infested with Rhyzopertha dominica, Sitophilus granarius, Oryzaephilus surinamensis and Cryptolestes ferrugineus, while rye was infested only with O. surinamensis. Kernels were tested in three different mechanical states: (A) whole undamaged kernels; (B) kernels already damaged by pests and (C) original storage kernels (mixture of B and C type). No P. interpunctella adult emerged on wheat kernels, while 36 adults developed on rye kernels. The highest abundance reached beetle species who fed with a mixture of kernels damaged by pests and whole undamaged kernels. Development and survival rate of five different storage insect pests depends on type of kernels and there exist significant survivorship correlations among them.

English

Farmers’ indigenous knowledge of storage insect pests and management practices in stored grain protection against insect pests are critical for sustainable food security in the smallholder sector in Zimbabwe. A survey was conducted among 48 and 51 maize farmers in wards 9 and 10 Bikita district respectively, to evaluate their knowledge, attitudes and traditional maize storage management practices against storage insect pests. The selected farmers grew maize and a variety of vegetables for subsistence. Problem storage pests listed in order of prevalence were maize weevil (Sitophilus zeamais) 49%, lesser grain borer (Rhizopertha dominica) and maize weevil (Sitophilus zeamais) complex 25.5%, lesser grain borer (Rhizopertha dominica) 17.7% and larger grain borer (Prostephanus truncatus) 7.3%. The commonly used botanical pesticides in the two wards were gumtree (Eucalyptus spp) (24.6%), tamboti (Spirostachys africana) (7.2%), lilac tree (Melia azedarach) (4.1%), sunflower (Helianthus annuus) ash (5.1%), cow dung (3.1%), lemon bush (Lippia javanica) (2%), murwiti (Rapanea melanophloeos) (1%), sweet basil (Ocimum basilicum) (1%) and finger millet (Eleucine coracana) chuff (1%),wood ash (4.1%) and mixtures of the above mentioned botanicals (4.5%). The botanicals are mixed with maize grain before storage either in sealed hessian bags or as loose grain placed in the granary plastered with cow dung. The use of botanicals was more prevalent in Ward 10 (100%) than ward 9 (14.7%). Farmers resort to the use of cheap and locally available botanicals when there is no money to buy synthetic insecticides. There is an urgent need for laboratory evaluation of the efficacy, chemical composition and mode of action in order to come up with dosage guidelines of these ethnobotanicals for the resource poor smallholder farmers. Key words: Indigenous knowledge, ethnoecological knowledge, ethnobotanicals, Sitophilus zeamais, Rhizopertha dominica, Prostephanus truncatus, synthetic insecticides, smallholder farmers.

Numerical investigation of low relative humidity aeration impact on the moisture content of stored wheat

High moisture content wheat kernels are subject to elevated respiration rates due to enzyme activity and mould growth that reduce the dry grain and may produce sufficient energy which may be harmful to wheat quality. Grain aeration provides a powerful nonchemical stored grain insect management. Currently, aeration is a suitable and economical device to overcome this problem. The moisture management is vital to prevent spoilage in stored grain. The objective of this study is to investigate the influence of using low relative humidity (RH) aeration on the wheat moisture content. The numerical investigation based on heat and mass balances is developed and used to simulate the evolution of grain temperature and moisture under various air RH in a wheat storage silo. Results show that the dehumidification of blown air had greater potential for decreasing RH of interstitial air and wheat moisture at [Formula: see text]C temperature and RH of 40%, 50% and 60%.