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Maize is a major staple food in Africa, its production and post-harvest generally occurs on smallholder farmers' properties, where significant food losses occur in the field during harvesting, processing and storage. Most smallholder farmers lack access to modern methods of harvesting, processing and storage. Generally, the storage structures used are ineffective against storage pests, leading to postharvest losses due to insect pests that, in some cases, can reach about 40% of the total production. Pest control is generally scarce, and when adopted, it is based on local knowledge-based pest control alternatives or on the application of synthetic pesticides known to be harmful to the environment and human and animal health. So, alternative pest control methods commonly found include the use of inert dust as an integrated pest management approach, without residual effects and ideal for food safety. This study aimed to determine the efficacy of charcoal powder (CP) and rock dust (RD) alone or combined with diatomaceous earth (DE) in the control of rice weevil (Sitophilus oryzae). Maize grains were treated and infested by the addition of Sitophilus oryzae, on the day they were treated and, 30 and 60 days after treatment. Mortality was assessed at 10 and 20 days after each infestation. Emerged insects were counted 40 days after the second mortality assessment for each infestation period. At 90 days after treatment, the seed germination test was performed. The best treatments for Sitophilus oryzae control (mortality) and F1 emergence reduction were RD (0.5, 0.25 and 0.10 g/kg), RD+DE (0.5+0.05, 0.25+0.05 and 0.10+0.05 g/kg), and CP+DE (1.0+0.05, 0.50+0.05 and 0.25+0.05 g/kg). The RD and RD+DE remained efficient in maize treated and stored for 60 days. The treatments did not interfere with seed germination. Rock Dusts, RD+DE, and CP have the potential to be used as stored grain protectants, providing economically and environmentally friendly pest control alternatives, especially in small-scale agriculture. In developing countries, especially in sub-Saharan Africa, studies for optimization and introduction of inert dusts tested in this research, have the potential to reduce post-harvest losses, improving food security. [ABSTRACT FROM AUTHOR]

ABSTRACTControlling grain temperatures is the main approach employed in large commercial warehouses to maintain quality and prevent infestation by insects and fungi. Large commercial warehouses in northeast China have been utilizing inner cyclic cooling aeration (ICCA), a newly developed method for managing summertime temperatures, haphazardly and without tight standards. We utilized a homemade detector to track the temperature, humidity, and CO2 concentrations of maize that was held for four years under ICCA treatment. The monitoring occurred every week, specifically from July 1st to September 30th. In addition, we conducted weekly tests to determine the moisture content (MC) and free fatty acids (FFA) of the stored maize samples. Without the use of ICCA, the average temperature of the stored maize above a depth of 3.5 m ranged from 20°C to 28°C, and the relative humidity (RH) in the headspace was typically higher than 75%. However, when ICCA was applied, the average temperature could be maintained at 22°C, and the RH was below 65% for most of the time. In the first year, the MC of the stored maize at a depth of 1.0 m experienced a loss of approximately 0.5%. However, for one year, there was no significant loss in the MC of the maize stored at the same depth. Furthermore, the FFA in the stored maize at a depth of 1 m increased by 1–5 mg KOH/100 g. The use of ICCA effectively controls the temperature and RH in the stored maize, reducing the risk of insect and fungal reproduction.

The repellency of solvent extracts of Calpurnia aurea leaves was evaluated on the maize weevils and the red flour beetles. Nine-cm Whatman number 1 filter paper that is partitioned into treatment, neutral and non-treatment portions was used for the experiment. Each solvent extract treatment was applied at 2.5, 5 and 10% rates. Insects were released in the neutral portion, while the untreated part served as a control. A choice bioassay experimental method that is laid down in a completely randomized design within three replications was used. 5 and 10% rates of the polar solvent extracts of Calpurnia aurea leaves induced significantly (p

Synthetic chemicals continue to play an important role in reducing storage losses attributable to insect pest activities. However, the adverse effects associated with some patented chemicals make synthetic pesticides less attractive and have given the drive to search for alternative methods of pest control. This study evaluated the effects of a traditional gin, akpeteshie crude extracts made of four timber species, neem (Azadirachta indica), mahogany (Khaya senegalensis), teak (Tectona grandis) and cedrela (Cedrela odorata) on the maize weevil Sitophilus zeamais on stored maize grains in the laboratory. Home-made extracts of the test tree plants at concentrations of 0.5, 1.0 and 2% were tested as grain protectants or as insect poisons. All tested extracts in their respective concentrations performed well in the reduction of live insects during maize storage as compared to a non-extract treatment. The mode of action of all the extracts was generally concentration and time-dependent. On average neem extract was the most effective followed by mahogany, teak, and cedrela in that order. Neem and mahogany extracts performed well in reducing grain damage at a concentration of 2% and at 0.5% concentration of cedrela extract respectively. All extracts reduced progeny emergence and acted both as a repellent or a toxicant. The extracts performed better as compared to the untreated control in the viability of maize seeds leading to germination, and subsequent seedling emergence. The relatively low weight loss of the stored grains treated with these crude extracts during the 90-day experimental period at a maximum concentration of 2% is predictive that they can be adopted as safe and alternative grain protectants against weevils in store. The unknown phytochemicals in these akpeteshie hardwood extracts may be responsible for the insecticidal properties against the weevils. For some concentrations of the extracts, germination was inconsistent which led to the suspicion of allelopathy.

Controlling grain temperatures is the main approach employed in large commercial warehouses to maintain quality and prevent infestation by insects and fungi. Large commercial warehouses in northeast China have been utilizing inner cyclic cooling aeration (ICCA), a newly developed method for managing summertime temperatures, haphazardly and without tight standards. We utilized a homemade detector to track the temperature, humidity, and CO2 concentrations of maize that was held for four years under ICCA treatment. The monitoring occurred every week, specifically from July 1st to September 30th. In addition, we conducted weekly tests to determine the moisture content (MC) and free fatty acids (FFA) of the stored maize samples. Without the use of ICCA, the average temperature of the stored maize above a depth of 3.5 m ranged from 20°C to 28°C, and the relative humidity (RH) in the headspace was typically higher than 75%. However, when ICCA was applied, the average temperature could be maintained at 22°C, and the RH was below 65% for most of the time. In the first year, the MC of the stored maize at a depth of 1.0 m experienced a loss of approximately 0.5%. However, for one year, there was no significant loss in the MC of the maize stored at the same depth. Furthermore, the FFA in the stored maize at a depth of 1 m increased by 1–5 mg KOH/100 g. The use of ICCA effectively controls the temperature and RH in the stored maize, reducing the risk of insect and fungal reproduction. [ABSTRACT FROM AUTHOR]

The repellency of solvent extracts of Calpurnia aurea leaves was evaluated on the maize weevils and the red flour beetles. Nine-cm Whatman number 1 filter paper that is partitioned into treatment, neutral and non-treatment portions was used for the experiment. Each solvent extract treatment was applied at 2.5, 5 and 10% rates. Insects were released in the neutral portion, while the untreated part served as a control. A choice bioassay experimental method that is laid down in a completely randomized design within three replications was used. 5 and 10% rates of the polar solvent extracts of Calpurnia aurea leaves induced significantly (p < 0.05) higher percentage weevils and beetles repellency (≥50.00%) at 2 days after treatment than non-polar and partial polar solvent extract treatments and the untreated check. 10% dosage of Calpurnia aurea leaves' polar solvent extract treatments caused 100% weevils and beetles repellency three days after treatment. Consequently, the polar solvent extracts of the tested plant were potent and could be used at 5 and10%rates for the maize weevils and the red flour beetles' management under farmers' maize storage conditions. Nevertheless, their impact on cost-effectiveness, natural enemies and human beings needs additional study. [ABSTRACT FROM AUTHOR]

Maize-dependent populations in sub-Saharan Africa are continually exposed to aflatoxin poisoning owing to their regular consumption of this dietetic cereal. Being a staple in Kenyan households, consumption of maize-based meals is done almost daily, thereby exposing consumers to aflatoxicoses. This study assessed awareness levels, knowledge disparities, and perceptions regarding aflatoxin contamination at the post-harvest phase among farmers in the Rift Valley Region of Kenya. Households were randomly selected using a geographical positioning system (GPS) overlay of the agro-ecological zones within Uasin Gishu and Elgeyo Marakwet counties. Face-to-face interviews were conducted in 212 smallholder and large-scale farms. The study documented the demographic profiles of farmers and knowledge, awareness, and perceptions of aflatoxin contamination using a pre-designed structured questionnaire. Most farmers were familiar with aflatoxins and the adverse effects they present to health (61.32%). Almost all the farmers (94.37%) were aware of storage molds and food-spoilage fungi. However, few farmers adopted good post-harvest practices (PHPs), such as avoiding premature harvests (49.8%), using well-ventilated storage spaces (44.6%), grain sorting (30.5%), proper drying of maize (17.8%), and using hermetic bags for storage (30.5%). Conclusively, intensified farmer education is required to train farmers on good PHPs to protect their maize from aflatoxigenic fungi and aflatoxin accumulation. [ABSTRACT FROM AUTHOR]

The edible plant, Piper guineense Schum and Thonn, belongs to the family Piperaceae and possesses insecticidal properties against stored product insects, but information on isolation and use of its amide alkaloids for the control of insect pests is scanty. Therefore, amide alkaloids from P. guineense fruits as well as its crude extract were investigated as protectant against Sitophilus zeamais Motschulschy (Coleoptera: Curculionidae), a cosmopolitan insect pest. Chemical analysis of P. guineense was done using chromatographic techniques and amide alkaloids were identified using liquid chromatography–quadrupole time of flight-mass spectrometry (LC-QToF-MS). The compounds were assayed on five pairs of two-day-old S. zeamais, feeding with the maize variety, TZPB-SR-W. All parameters, including mortality and oviposition by female S. zeamais, repellent effect of the compounds and their effects on maize seed germination, were evaluated relative to the synthetic chemical, pirimiphos-methyl and ethanol, as positive and negative controls, respectively. The six compounds identified were dihydrowisanine (1.01%), guineensine (0.22%), piperine (6.64%), piperlonguminine (0.25%), propiverine (0.16%) and trichostachine (3.80%). Guineensine and piperine caused the highest mortalities (97.5% and 82.5%, respectively) of S. zeamais, which were not significantly different from the mortality (100%) caused by pirimiphos-methyl. In addition, piperine treatment significantly reduced oviposition (0.75 per grain) when compared to ethanol-treated grains (5.00 per grain). There were no significant differences in per cent germination between maize seeds treated with the amide compounds and those included in the control groups (positive and negative controls). Amide alkaloids from P. guineense offer a useful source of biopesticide material for controlling S. zeamais. [ABSTRACT FROM AUTHOR]

Grain losses due to moulds during on-farm storage increase food insecurity, result in economic losses, negatively affect farmers’ livelihoods, and increase exposure to mycotoxins that can harm human and animal health. Hermetic storage technologies provide a reliable solution for maize grain that may also preserve food safety. Several studies report the effectiveness of these technologies against post-harvest insects in Africa but provide limited evidence on effectiveness against mould proliferation and mycotoxin contamination. Hermetic technologies were superior to farmer practice in reducing insect infestations and mycotoxin accumulation. Among hermetic technologies, there were no significant differences (P>0.05) in performance between metal silos and hermetic bags for mycotoxin accumulation and insect infestation regardless of the mode of infestation. In non-inoculated grain, fungal populations were varied but included mycotoxin-producing Aspergillus and Fusarium spp., indicating that the grain was naturally contaminated and acted as a good reservoir for these fungi. Mycotoxin levels increased with higher moisture even in non-inoculated grain. Meanwhile, aflatoxin and fumonisin levels at 4 months were not significantly different from baseline values in dry inoculated grain across all storage technologies (P>0.05), indicating that hermetic technologies can prevent mycotoxin contamination in dry grain for at least 4 months of storage. Aflatoxin and fumonisin were significantly higher by 1.69 ppb and 0.25 ppm respectively in non-inoculated grains at high moisture indicating the need to adequately dry grain before storage in hermetic technologies. This trend was observed collectively in all the technologies registering 2.03 ppb and 0.311 ppm respectively. In inoculated grains at high moisture, there was an increase in aflatoxin in both hermetic treatments and the control by 5.7 ppb and 12.14 ppb respectively. Therefore, a trial was conducted to compare hermetic technologies with farmer practice in their effectiveness against both insect infestation and mycotoxin contamination.

ECO₂FUME® fumigation of maize bag stacks under gas proof sheets was conducted to establish the optimal dosages (application rate) and exposure times (fumigation period) against mixed-age cultures of Sitophilus zeamais and Tribolium castaneum. The Complete Randomized Design (CRD) experimental design was employed, with 3 replications and 4 treatments. The experiments were divided into three groups: 1) treatment with a 25 g/m3 ECO₂FUME® application rate (350 ppm phosphine) for 3, 4, and 5 days and a control treatment; 2) treatment with an ECO₂FUME® application rate of 50 g/m3 (700 ppm phosphine) for 2, 3, and 4 days and a control treatment; and 3) treatment with a 70 g/m3 ECO₂FUME® application rate (1,000 ppm phosphine) for 1, 2, and 3 days and a control treatment. The three target phosphine concentrations of 350 ppm, 700 ppm and 1,000 ppm were maintained during the whole fumigation period. Results of the studies showed that no insect was alive at all dosages and exposure times. The studies also indicated that fumigation with ECO₂FUME® could reduce the fumigation period by increasing the phosphine concentration. The effective fumigation protocols on maize against mixed-age cultures of S. zeamais and T. castaneum were ECO₂FUME® application rates of 25 g/m3 for 3 days, 50 g/m3 for 2 days and 70 g/m3 for 1 day. The target phosphine concentration must be maintained throughout the fumigation period to achieve 100% mortality of all stages of insects.

Millettia ferruginea leaf solvent extracts were tested for repellency against the most important pests of stored maize; the maize weevils and the red flour beetles. 2.5%, 5%, and 10% dosages were applied in 9 cm Whatman number 1 filter paper, with dividing it into three parts. The untreated portion was used as a control, while the neutral was served as the insect release portion. Significantly (P 55%) repellency was recorded in all M. ferruginea leaf polar solvent extracts applied at rates of 5% and 10%, at 2 days after treatment than nonpolar and partial polar solvent extract treatments, and the untreated check. One hundred percent weevils and beetles repellency were recorded in all M. ferruginea leaf polar extract treatments applied at rates of 10%, at 3 days after treatment. Therefore, the M. ferruginea leaf polar solvent extracts were potent, and they could be used in the management of the maize weevils and the red flour beetles in stored maize, at 5% and 10% dosages, under farmers’ storage conditions in Ethiopia. However, the crude extracts effect on a human beings, natural enemies, and the cost-effectiveness under farmers’ storage conditions needs further study.

Millettia ferruginea leaf solvent extracts were tested for repellency against the most important pests of stored maize; the maize weevils and the red flour beetles. 2.5%, 5%, and 10% dosages were applied in 9 cm Whatman number 1 filter paper, with dividing it into three parts. The untreated portion was used as a control, while the neutral was served as the insect release portion. Significantly (P <0.05) higher percentage weevils and beetles (>55%) repellency was recorded in all M. ferruginea leaf polar solvent extracts applied at rates of 5% and 10%, at 2 days after treatment than nonpolar and partial polar solvent extract treatments, and the untreated check. One hundred percent weevils and beetles repellency were recorded in all M. ferruginea leaf polar extract treatments applied at rates of 10%, at 3 days after treatment. Therefore, the M. ferruginea leaf polar solvent extracts were potent, and they could be used in the management of the maize weevils and the red flour beetles in stored maize, at 5% and 10% dosages, under farmers' storage conditions in Ethiopia. However, the crude extracts effect on a human beings, natural enemies, and the cost-effectiveness under farmers' storage conditions needs further study. [ABSTRACT FROM AUTHOR]

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The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) is one of the most destructive insect pests of stored maize and dried tubers of cassava, and a wood-boring species. In the present study, we examined two chlorantraniliprole formulations, WG (wettable granule) with 350 g/kg active ingredient (a.i.) and SC (suspension concentrate) with 200 g/L a.i., as maize protectants against P. truncatus adults. Chlorantraniliprole formulations were applied as solutions at 0.01, 0.1, 1 and 10 ppm, and tested at 20, 25 and 30 °C. Both formulations performed similarly. After 7 days of exposure, the overall mortality provided by both formulations was very low (T. truncatus on stored maize that depends on temperature, dose and exposure interval. The fact that chlorantraniliprole is a broad-spectrum insecticide, exhibiting low toxicity to mammals and beneficial arthropods, could be a valuable management tool in storage facilities.

ABSTRACT: Five Zea mays cultivars (BRS Caatingueiro, BRS Gorutuba, BRS Sertanejo, BRS Asa Branca and BR 106) were evaluated considering their effect on the nutrition of the maize weevil Sitophilus zeamais, by analysis of total protein in adult fed with these cultivars and for the presence of lectins and trypsin inhibitors in grains. In addition, free-choice and no-choice assays were performed to investigate the resistance of grains of the Z. mays cultivars to an attack by S. zeamais. The BR 106 cultivar showed the lowest susceptibility index, followed by BRS Caatingueiro, BRS Asa Branca, BRS Sertanejo and BRS Gorutuba. The number of emerged adults in the Z. mays cultivars ranged from 213.17 to 74.0, and the lowest number of insects was recorded for the BR 106 cultivar. The insects were able to feed on grains of all cultivars, but the BR 106 cultivar showed the least reduction in dried biomass. Lectins were detected in extracts from BR 106, BRS Asa Branca, BRS Sertanejo and BRS Gorutuba, and the highest activity was shown by BR 106. The lowest protein assimilation was detected in the insects from treatments with BRS Asa Branca. The extracts from all cultivars were able to inhibit the activity of bovine trypsin, but this effect was not related to the resistance degree of Z. mays cultivars. The results suggest the resistance of BR 160 to the attack of S. zeamais, as well as indicating that the presence of lectin in the grains is the cause of this resistance.

ECO2FUME® fumigation of maize bag stacks under gas proof sheets was conducted to establish the optimal dosages (application rate) and exposure times (fumigation period) against mixed-age cultures of Sitophilus zeamais and Tribolium castaneum. The Complete Randomized Design (CRD) experimental design was employed, with 3 replications and 4 treatments. The experiments were divided into three groups: 1) treatment with a 25 g/m3 ECO2FUME® application rate (350 ppm phosphine) for 3, 4, and 5 days and a control treatment; 2) treatment with an ECO2FUME® application rate of 50 g/m3 (700 ppm phosphine) for 2, 3, and 4 days and a control treatment; and 3) treatment with a 70 g/m3 ECO2FUME® application rate (1,000 ppm phosphine) for 1, 2, and 3 days and a control treatment. The three target phosphine concentrations of 350 ppm, 700 ppm and 1,000 ppm were maintained during the whole fumigation period. Results of the studies showed that no insect was alive at all dosages and exposure times. The studies also indicated that fumigation with ECO2FUME® could reduce the fumigation period by increasing the phosphine concentration. The effective fumigation protocols on maize against mixed-age cultures of S. zeamais and T. castaneum were ECO2FUME application rates of 25 g/m3 for 3 days, 50 g/m3 for 2 days and 70 g/m3 for 1 day. The target phosphine concentration must be maintained throughout the fumigation period to achieve 100% mortality of all stages of insects. [ABSTRACT FROM AUTHOR]

Diatomaceous earths (DEs) are able to successfully protect grain commodities from noxious stored-product insect and mite infestations; however, their effectiveness may be moderated by the grain hybrid or variety they are applied to. There is a gap of information on the comparison of the efficacy of different DEs when are applied on different maize hybrids against Prostephanus truncatus (Horn). Therefore, here we tested three commercially available DEs (DEA-P at 75 and 150 ppm, Protect-It at 500 ppm, and PyriSec at 500 ppm) on five different maize hybrids (Calaria, Doxa, Rio Grande, Sisco, and Studio) for the control of P. truncatus adults in terms of mortality (at 7 and 14 days), progeny production, properties of the infested maize hybrids (number and weight of kernels with or without holes, number of holes per kernel) and the adherence level of the tested DEs to the kernels. DEA-P was very effective at 75 ppm while a considerable proportion of the exposed P. truncatus adults was still alive after 14 days of exposure on all maize hybrids treated with 500 ppm of Protect-It or PyriSec, even though it was 3.3 times higher than the maximal application tested dose of DEA-P. Apart from parental mortality, DEA-P was able to reduce P. truncatus progeny production in all hybrids contrary to Protect-It or PyriSec. The adherence ratios were always higher for DEA-P than Protect-It or PyriSec to all maize hybrids. The highest numbers of kernels (or weight of kernels) without holes were noticed after their treatment with DEA-P. Doxa and Sisco performed better than Calaria, Rio Grande, or Studio based on the differences found concerning the numbers of kernels without holes at treatments with DEA-P and Protect-It. Overall, the findings of our study indicate the high potentiality of DEA-P as protectant of different maize hybrids to P. truncatus infestations at low doses, a fact that could help the eco-friendly management of this noxious species in the stored-product environment. [ABSTRACT FROM AUTHOR]

Maize plays a key role in household food security in Ethiopia, but its benefit has been limited with high post-harvest losses. This study was initiated to assess post-harvest practices and associated fungi pathogen epidemiology along the maize supply chain in southwestern Ethiopia. The study was conducted in five purposively selected districts and a three-stage sampling procedure was employed for selection of the target groups. In total, 342 participants from different actors were interviewed using a semi-structured questionnaire. Maize samples were collected every month from 63 randomly selected actors for mycological analysis during six months storage period. Post-harvest loss was estimated to be 31% and loss during storage was identified as a critical loss point. Comparing all biological agents, loss due to fungal pathogens in the store ranked on top. Moisture content at loading stage could not increase the shelf life of the commodity. Germination tests showed a significant (P < 0.01) decrease as storage duration increased, while mould incidence on cobs and kernels significantly (P < 0.05) increased. In total, seven fungal genera were isolated, characterized and identified, with Fusarium, Penicillium and Aspergillus being predominant. Most of the post-harvest practices are not effective in reducing post-harvest losses. Especially, farmers’ traditional storage structures can be influenced by external climatic conditions and make the grains liable to develop mould during the rainy season. This research, therefore, highlights the need to design, develop or modify existing storage technologies that reduce post-harvest loss due to mycotoxin-producing fungal pathogens. Furthermore, postharvest drying to obtain optimum moisture content is also crucial to reduce losses. [ABSTRACT FROM AUTHOR]

Laboratory studies were conducted to evaluate the insecticidal potential of extracts of eight plants viz. lemon grass (Cymbopogon flexousus), turmeric (Curcuma longa), basil (Ocimum basilicum), harmal (Peganum harmala), heeng (Ferula assa-foetida), neem (Azadirachta indica), tumma (Citrullus colocynthis) and mint (Mentha arvensis) against maize weevil, Sitophilus zeamais using three concentrations (5, 10 and 15%) at three time intervals (2, 4 and 6 days) in the laboratory. The results revealed that maize weevil mortality was increased with the increase in concentration and time interval. Maximum mortality (86.67%) of the pest was observed with the use A. indica extract at 15% concentration after 6 days of application followed by C. colocynthis extract (81.66%), P. harmala (76.66%), C. longa (71.67%), O. basilicum (66.66%), F. assafoetida (61.66%), C. flexousus (58.33%) and M. arvensis (53.33%). The lowest mortality (22.78%) was observed against lowest concentration of C. flexousus. Overall results show that mortality of the insect increased with the increase in concentration and exposure time. [ABSTRACT FROM AUTHOR]

In Rwanda, management of stored maize insect pests is based on conventional chemical insecticide applications with high residues. Organic pesticides containing pyrethrins like Agrothrin® (Dusting powder, Agropharm Ltd., Kigali, Rwanda) containing 0.11% pyrethrins, 1.1% piperonyl butoxide (PBO) synergist (w/w), a natural extract from the African pyrethrums with no side effects, can be a suitable option for managing stored maize. The present study was conducted to determine insecticidal and grainprotecting properties of Agrothrin against the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), under both laboratory (controlled) and warehouse (non-controlled) conditions. The product was tested at seven different doses ranging from 0.9 kg/ton to 2.1 kg/ton and compared with an untreated control (control-) and a conventional chemical insecticide control (malathion, control+). The results from the study revealed that insecticidal activity of Agrothrin was low and not quick but it was more than doing nothing because it caused mortalities more than 95% of artificially introduced insects after 5 and 6 weeks. However, higher doses superior to 1.7 kg/ton and/or longer exposures than 4 weeks were needed to obtain an adult mortality more than 95%. In addition, Agrothrin gave effective grain protection against S. zeamais and the insects were predominantly present in positive and negative controls but absent or in low number in grains treated with Agrothrin. This indicates that the product can be used as an effective grain protectant for newly harvested maize grains before storage. Overall results suggest that Agrothrin may be a very effective alternative to the existing conventional chemical insecticides in stored maize protection at doses equal to or higher than 1.7 kg/ton of grain. [ABSTRACT FROM AUTHOR]

The tropical warehouse moth Ephestia cautella (Walker) is an important storage pest of maize grain. The control of this major moth pest relies heavily on the use of synthetic insecticides. We assessed the biological efficacy of a commercial neem oil (Calneem oil) against E. cautella in the laboratory, using the common grain protectant Actellic as a positive control. Contact toxicity, repellency, effects on oviposition, development and grain damage were assessed. The assays were conducted by treating 100 g of maize grains with Calneem oil concentrations of 3, 5 and 7 ml/l; and Actellic at 2 ml/l. Calneem oil significantly (P < 0.05) reduced oviposition rate, development of eggs and immature stages, and emergence rate of E. cautella progeny in maize grains. Grains treated with Calneem oil had significantly (P < 0.05) reduced grain damage in storage, and the oil had a repellency of 53–70% compared with the negative control. Calneem oil protected maize grain against damage by E. cautella for 10 weeks, compared with 20 weeks protection by Actellic. There was no resistance development to the oil for three generations of E. cautella. The insects that survived treatment with the LC90 concentration (12.2 ml/l) of the Calneem oil laid fewer eggs, and some of their progeny were deformed. Calneem oil provided a good level of protection to maize grains against infestation by E. cautella, and may therefore be a suitable substitute for Actellic. [ABSTRACT FROM AUTHOR]

The study sought to confirm reports by farmers and agricultural extension personnel of Prostephanus truncatus (Horn) attacking harvested maize in Mashonaland West and Mashonaland Central provinces of Zimbabwe and to map out, using pheromone trap catch data, the distribution of the pest in the country. A survey of 296 respondents confirmed the presence of P. truncatus in five districts of the provinces. Some respondents reported that the first few sightings of the pest were in 2005 or earlier, while the majority mentioned the 2006/2007 storage season. The map showed a more concentrated distribution of P. truncatus in the northern part of the country moving further inland towards the central and eastern parts of Zimbabwe, indicating possible spread of the pest from the neighbouring countries Zambia and Mozambique. The results of the study indicate legitimate concerns over food security with respect to stored maize grain and seed. The occurrence of P. truncatus in the country has serious implications on training of extension agents and packaging of extension messages that need to be disseminated to the farming community to reduce the impact of the pest. This is the first evidence-based and official documented report of P. truncatus occurrence in Zimbabwe. [ABSTRACT FROM AUTHOR]

Laboratory experiments were carried out to evaluated three diatomaceous earth (DE) formulations—Protect-It, PyriSec (at dose rates 500, 1,000, and 1,500 ppm), and DEA-P (at dose rates 75, 150, and 500 ppm)—against the larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae), adults in stored maize, Zea mays L., at three temperatures (20, 25, and 30°C) and two relative humidity (RH) levels (55 and 75%). At these conditions, the capability of progeny production in the treated substrate also was assessed. Adult survival was high, at all doses of Protect-It and PyriSec. Progeny production was also high. In contrast with the other two DEs, DEA-P was highly effective and caused complete mortality to the exposed P. truncatus adults, even at the lowest dose rate (75 ppm). In addition, progeny production was completely suppressed. Generally, Protect-it and PyriSec were more effective at 20°C than at 30°C. In contrast, the efficacy of DEA-P was continuously high in all temperatures and relative humidities examined. [ABSTRACT FROM AUTHOR]

Simple Summary: Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) is a major insect pest of stored maize and dried tubers of cassava, but also a wood-boring species. In the current study, we evaluated two chlorantraniliprole formulations, WG (wettable granule) and SC (suspension concentrate), as maize protectants against P. truncatus adults at 20, 25 and 30 °C. Both formulations performed similarly. The highest mortality was noted in chlorantraniliprole WG, at 10 ppm and 30 °C (98.9%), followed by chlorantraniliprole SC (96.1%), at the same dose and temperature. WG formulation was more effective at 10 ppm and 25 °C (92.8%) than SC formulation (89.4%). No progeny production was noted on maize treated the WG formulation at 20 and 30 °C. The SC formulation caused complete offspring suppression at 10 ppm at all three tested temperatures. The results indicate that chlorantraniliprole is an effective compound with a high insecticidal activity against T. truncatus that depends on temperature, dose and exposure. The larger grain borer, Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) is one of the most destructive insect pests of stored maize and dried tubers of cassava, and a wood-boring species. In the present study, we examined two chlorantraniliprole formulations, WG (wettable granule) with 350 g/kg active ingredient (a.i.) and SC (suspension concentrate) with 200 g/L a.i., as maize protectants against P. truncatus adults. Chlorantraniliprole formulations were applied as solutions at 0.01, 0.1, 1 and 10 ppm, and tested at 20, 25 and 30 °C. Both formulations performed similarly. After 7 days of exposure, the overall mortality provided by both formulations was very low (<17%). Seven days later, mortality was remarkably increased on maize treated with 1 and 10 ppm at 25 and 30 °C for both formulations. The highest mortality was noted in chlorantraniliprole WG, at 10 ppm and 30 °C (98.9%), followed by chlorantraniliprole SC (96.1%), at the same dose and temperature. WG formulation was more effective at 10 ppm and 25 °C (92.8%) than SC formulation (89.4%). No progeny production was noted on maize treated with the WG formulation at 20 and 30 °C. The SC formulation caused complete offspring suppression at 10 ppm at all three tested temperatures. The results of the present work indicate that chlorantraniliprole is an effective compound with a high insecticidal activity against T. truncatus on stored maize that depends on temperature, dose and exposure interval. The fact that chlorantraniliprole is a broad-spectrum insecticide, exhibiting low toxicity to mammals and beneficial arthropods, could be a valuable management tool in storage facilities. [ABSTRACT FROM AUTHOR]

A distributed-delay, demographic simulation model of Prostephanus truncatus (Horn) populations in rural maize (Zea mays L.) stores was developed and validated. Developmental and mortality parameters for eggs, larvae, and pupae, and the life span and fecundity data for adult insects, were estimated from published data and from laboratory experiments. The overall phenology of the simulated beetle dynamics reflected that of field data, although the model output tended to overestimate beetle population growth during the season and overall density late in the season. The model was de eloped as part of a low-cost tool for evaluating the major factors influencing population dynamic of stored-product pests and their natural enemies and to provide a conceptual framework for evaluating different control strategies in an integrated control context. [ABSTRACT FROM AUTHOR]