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Maize is a staple food in Ghana where there is ever increasing demand for its use to also support poultry and livestock production. However, post-harvest loss of maize is high in Ghana. This study evaluated the effectiveness of plastic and steel bins as bulk storage structures to reduce maize post-harvest loss in Ejura, Ghana during the period from February 2016 to January 2017. Maize pre-disinfested with a solar biomass hybrid dryer was stored in the following treatments: i. a white 7-ton plastic bin filled with untreated maize, ii. agreen 7-ton plastic bin filled with untreated maize, iii.a 6-ton Kikapu steel bin filled with untreated maize, iv. six 50-kg polypropylene (PP) bags filled with maize treated with Betallic Super (80 g pirimiphos-methyl and 15 g permethrin per liter as an emulsifiable concentrate (EC)), and v. six 50-kg PP bags filled with untreated maize ascontrol. Moisture content, insect pests, insect damaged kernels (IDK), grain weight loss, aflatoxin and fumonisin levels data were collected monthly. Sitophilus zeamais, Tribolium castaneum, Cathartus quadricollis, and Cryptolestes ferrugineus were the dominant insect species collected from maize samples. At the end of 12 months of storage, % IDK in the control was >17% while IDK values in the other treatments were

With the phase-out of methyl bromide, treatment of food facilities with aerosol insecticides as part of management programs has increased. The physical layout of the structure, the distribution of equipment and other items within the space, and the application method and location may all cause spatial variation in how the insecticide is deposited, which can result in areas with insufficient or excessive amounts of insecticide applied. The impact of aerosol insecticide application position and dispersal method/formulation on the distribution of droplets was evaluated using a series of applications within the same flour mill room. The spatial pattern of droplet distribution and the effect of treatment on bioassay insects (Tribolium confusum Jacquelin DuVal) was evaluated. There was variation in aerosol concentration and droplet size distributions within room and application position had an impact on the spatial pattern of aerosol droplets. The further away and more obstructed by structural features a location was the lower the aerosol concentration, but concentration was also lower to the side and behind the release point. Evaluation of the temporal pattern in droplet deposition shows that most larger droplets settle out of the air relatively quickly, supporting that idea that shorter shutdown times are be possible. Efficacy was correlated with droplet concentration. The overall conclusion is that there can be considerable variation in distribution of aerosol insecticides and as a result considerable potential for improvement in the effectiveness of these applications.

Improper or poor post-harvest handling and storage of stored grains contributes significantly to product loss, and bagged stored grain presents an option for safe storage and handling. Bagged grain is intended to maintain quality and safety, while protecting it from infestations. The objective of this research was to determine the effect of deltamethrin-treated packaging material on adults and larvae of common stored product pests. Adults or larvae of several species of stored product insects were exposed to deltamethrin-treated packaging for time intervals ranging from 1 h to 4 weeks. The percentage of affected Prostephanus truncatus, Callosobruchus maculatus and Rhyzopertha dominica adults was < 98% after 60 minutes of exposure to treated packaging. Mortality of adult Trogoderma granarium was about 33% after 1 day of exposure, and increased to 93% after 7 day of exposure. Direct mortality of T. granarium larvae exposed to the deltamethrin-treated packaging for 8 h was about 15%, but increased to 50% when larvae were exposed for 72 h. Tribolium castaneum, Oryzaephilus surinamensis, and Trogoderma inclusum larvae continually exposed to the deltamethrin-treated packaging resulted in > 96% larval death within 1-2 weeks.The major primary stored product insects were highly susceptible to the deltamethrin-treated storage bags, but there was variation in susceptibility between species and life stages tested. The deltamethrin-treated storage bags can offer protection of bagged grains and be used as a preventative measure to reduce infestations during storage.

Phosphine is a widely used fumigant for controlling insects in stored grain, but fumigation effectiveness is often compromised by suboptimal distribution of the gas. Leaks in the grain bin wall and roof, foreign material in the grain, and phosphine placement contribute to regions of insufficient concentration of fumigant, resulting in insect survival and leading to phosphine-resistant insect populations. Phosphine distribution was studied during field tests in temporarily sealed bins to compare distribution from conventional probed tablets to the distribution using a closed-loop recirculation system. The results showed uneven distribution patterns and leakage over time with conventional probed tablets, which resulted in some areas in the lower half of the grain mass receiving no phosphine and some other locations remaining below the target phosphine concentration for the entire period of fumigation. The closed-loop fumigations with the same phosphine dosage yielded much more uniform phosphine concentrations, but suffered from equal or greater phosphine leakage losses.

Monitoring is fundamental to integrated pest management programs since it provides feedback on effectiveness of prevention programs and helps with targeting interventions as needed and evaluating their effectiveness. Rice mills are spatially complex facilities that have a combination of rough rice storage bins, buildings where rice is milled and processed, and warehouses and bulk storage bins where finished product is held before shipment. Each of these structures can have its own suite of insect species, different levels of risk, as well as different suites of management tools available. At a large rice mill in Brazil, stored product insect activity was monitored using food bait traps placed around rough rice receiving areas and storage bins; inside building containing white rice mill, rice flour mill, and packaging; and inside building for processing parboiled rice. The facility was monitored from 2010 to 2018 with 100 traps. Major pest species recovered at the facility included Sitophilus oryzae, Sitophilus zeamais, Rhyzopertha dominica, Tribolium castaneum, Cryptolestes ferrugineus, Ahasverus advena, Oryzaephilus surinamensis, Typhaea stercorea, Anthicus floralis, and Nitidulidae species. Temporal and spatial patterns in abundance were evaluated for each of the major species and for major functional groups (primary feeders, secondary feeders, and fungal feeders). Monitoring data generated was used to guide pest management programs and also provided the information needed to develop management thresholds.

Although grain is always inspected for adult insects and insect damaged kernels upon shipping and receiving, immature insects living inside the kernels of grain cannot be readily detected. A laboratory roller mill was modified to measure and analyze the electrical conductance of wheat as it was crushed. The electrical conductance of normal wheat kernels is low and fairly constant. In contrast, the electrical conductance of infested wheat kernels produces a sudden change in the electrical signal. The peak height of the electrical spike depends on the size of the larvae and the resulting contact of the crushed larvae between the rolls. This instrument was designed to test wheat with moisture content of 13.5% or less. The laboratory mill can test a kilogram of wheat in less than 2 min. Hard red winter and soft red winter wheat samples were used in experiments. Known numbers of infested kernels were added to the wheat samples. The infested kernels contained larvae of rice weevils and lesser grain borers sorted into large, medium, and small size groups. The instrument detected ~8 of 10 infested kernels per 100 g of wheat with large-larvae (fourth instar or pupae). It detected ~7 of 10 infested kernels with medium-larvae (second or third instar) and ~5 of 10 infested kernels infested with the small‐larvae (first or second instar). Under reasonable grain moisture and careful sample handling, there were no non-infested kernels classified as insect infested. The mill can lead to rapid and automated detection of infested wheat.

Insect infestations and mycotoxin contamination contribute to postharvest degradation and crop loss in sub- Saharan Africa, including maize stored in Ghana. Surveys were conducted to assess the prevalence of insect pests and fungal pathogens in stored maize from the major and minor cropping seasons (September to December and January to April, respectively) that was stored on-farm and in retail markets in Ghana. Results show differences between the major and minor storage seasons for on-farm sites and retail markets. The presence of internal feeders such as Sitophilus zeamais (Motschulsky) was positivly correlated with insect-damaged kernels and percentage weight loss. Levels of aflatoxin were generally greater than the established threshold of 15 ppb early in the major crop storage season, while fumonisins were generally lower than threshold levels of 4.0 ppm in on-farm sites and in the retail markets.

Hydrogen phosphide (PH3) is the most commonly used gas for insect control in durable stored products. One of the quick diagnostic tests that are currently in use is the Detia Degesch Phosphine Tolerance Test Kit (DDPTTK), which has been developed by Detia Degesch GmbH (Laudenbach, Germany). DDPTTK provides a rapid evaluation tool for phosphine resistance, where insects are exposed in syringes that contain a high concentration of gas (e.g. 3000 ppm), while this gas is produced on site by adding tablets into a canister. We used DDPTTK to evaluate resistance of the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) to phosphine. For this purpose, we followed a specific succession of observations on the exposed adults of this species, in an effort to set the scene for designing a rapid diagnostic tool for phosphine resistance, based upon quick bioassays. Two T. castaneum strains were used, one susceptible and one resistant to phosphine. Twenty adults of each of the populations (separate sets of adults each time) were placed in syringe of 100 ml under 1000 or 3000 ppm of phosphine. The insects inside the syringe were monitored at 15-min intervals, for a total period of 90 min, and classified as active, under narcosis and immobilized. After this period, all insects were removed from the syringe and placed in plastic petri dishes with a small quantity of wheat flour. The insects were classified again at the three categories above, after 2 h, 1 d, 2 d, 3 d and 7 d. Regarding the exposure period, at 1000 ppm, all adults of the susceptible strain were immobilized after 60 min of exposure, and remained at this condition until the end of the observation period. At the same concentration, the majority of adults of the resistant strain remained active until the end of the observation period. At 3000 ppm, for the susceptible strain, all adults became immobilized after 90 min observation. For the same concentration, the percentage of the adults of the resistant strain that were active was notably reduced in comparison with 1000 ppm. For the post-exposure period, at 1000 or 3000 ppm, for the susceptible strain, the number of adults that were immobilized reached 95 % after 7 d. At the same phosphine concentration, almost all of the adults of the resistant strain were active even at the 2 h post-exposure period, and practically remain at this condition until the end of the observation period. Our findings indicate that time-to-narcosis / immobilization is inversely proportional to time-to-recovery of the same individuals, and this characteristic can be also considered as an indicator for resistance.

Maize post-harvest losses are perennial in Ghana but reliable comparative information on on-farm losses of maize produced in the Middle and Northern Belts of Ghana is lacking. Two studies were conducted from September 2015 to February 2016 to identify factors contributing to on-farm losses of maize in these two Belts. In the Northern Belt, the study was conducted in six communities including Adubiyili, Diari, Pong-Tamale, Savelugu, Toroyili and Zamnayili; and in the Middle Belt, in Ejura, Sekyedumase and Amantin communities. Moisture content, percent weight loss, percent insect damaged kernels (IDK) on numerical basis (%IDKnb) and percent IDK by weight basis (%IDKwb), insect pest abundance, and mycotoxin levels were estimated. Moisture content values of maize at pre-harvest and heaping stages in all nine communities were below 15%. Sitophilus zeamais, Sitotroga cerealella, Cathartus quadricollis, and Carpophilus dimidiatus were found to attack maize onfarm in communities in the Middle Belt, but no adult insect pests were collected on pre-harvested maize in the Northern Belt. The %IDKnb values on-farm in all nine communities were < 2% per 250 g. Mean aflatoxin levels below 15 ppb were obtained from pre-harvested maize in both regions but levels above 15 ppb were obtained from heaped maize on-farm. Fumonisin levels of maize were below 4 ppm on pre-harvested and in heaped maize in both regions. Results show that heaping maize on-farm increases aflatoxin levels beyond the acceptable threshold level and should not be practiced.