Stored Grain Research Articles

Ectoparasitoid Dinarmus basalis causes greater offspring loss to the winged morph of Callosobruchus maculatus

The pest cowpea weevil Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae) exhibits polymorphism with flight and flightless forms that differ in morphology and life-history. Flight forms are generally dispersers with lower fecundity that increase in frequency when population density and intraspecific competition are both high. Callosobruchus maculatus larvae can cause important damage to stored grains and the solitary ectoparasitoid Dinarmus basalis (Rondani) (Hymenoptera: Pteromalidae) is considered to be a good candidate biological control agent. However, whether morphs differ in the likelihood of their offspring surviving attack is unknown. Understanding this has implications for the pest status of the cowpea weevil following biological control. We found that attack by D. basalis lowered the number of emerging offspring produced by both morphs. The ectoparasitoid was most effective at reducing survival of larvae produced by flight morph parents, suggesting that there may be a further cost of dispersal for C. maculatus. Parental morph type did not influence D. basalis behavior or development when foraging, so the biological mechanism resulting in this difference remains unclear. Nevertheless, our study shows that D. basalis affects the offspring of both weevil morphs, as required for an effective biocontrol agent. These results contribute to our understanding of how intraspecific variation, including polymorphism, influences species interactions among biological control agents and their target insect pests.

Türkiye'deki Sitophilus oryzae L., 1763 ve Sitophilus granarius L., 1758 (Coleoptera: Curculionidae) popülasyonlarında malathion direncinin belirlenmesi

This study was conducted to determine the malathion resistance levels of two important stored grain pest beetles, Sitophilus oryzae L., 1763 and Sitophilus granarius L., 1758 (Coleoptera: Curculionidae), collected from different provinces of Türkiye in the years 2017-2018. To control these pests, chemical insecticides have been widely used for a long time as a grain protectant in farmer warehouses, flour mills, or silos in many countries, including Türkiye. In the current study, insects were exposed to malathion for 24 hours to determine resistance rates. The highest resistance ratio to malathion in S. oryzae was found in the Adana-Kartepe population with 5.73-fold, and the lowest resistance was found in the İstanbul- Büyükçekmece population with 1.57-fold. While the Konya-Alibeyhöyüğü population of S. granarius had the highest resistance ratio of 6-fold, the lowest resistance rate of 2.54-fold was found in the population obtained from the same location but from a different warehouse. According to this study, we found that slight resistance developed in the populations of S. oryzae and S. granarius in Türkiye. In order to prevent the occurrence of resistance due to synthetic insecticides used against stored product pests, it is thought that various insecticide groups with different mechanisms of action should be used.

Cellulose-Based Photothermal Coating: A Sustainable Solution for Seed Protection and Long-Term Grain Storage.

High-output modern agriculture based on synthetic chemicals (biocides, pesticides, and fertilizers) feeds the growing global population. To completely abandon the use of pesticides and fertilizers will undoubtedly cause a severe food crisis worldwide, and sustainable alternative solutions are urgently demanded to stop biocides and fertilizers overuse. Herein, a versatile and green strategy is proposed for seed protection and long-term storage of grains using a cellulose-based photothermal coating (PDA NPs@Cell-N+) that consists of photothermal polydopamine nanoparticles (PDA NPs) and a positive-charged cellulose derivative (Cell-N+) to eradicate seed-borne bacteria and fungi simply under infrared irradiation. In vitro and in vivo assays and the seedling-stage phenotypes of mung bean (Vigna radiata) suggest that pathogenic microbes, including the tough Aspergillus flavus (inhibition ratio >99%), can be efficiently eliminated by photothermal therapy. Thus, the seed-borne diseases of mung beans can finally be prevented. Owing to excellent solubility and biocompatibility, the PDA NPs@Cell-N+ coating can be washed off and recycled without food safety concerns. PDA NPs@Cell-N+ can be a nature-based solution for seed protection and long-term grain storage.

Biopesticidal activities of three botanicals (Ageratum conyzoides L., Petiveria alliacea L. and Hyptis suaveolens L. Poit,) against Sitophilus oryzae L

This study was carried out to evaluate the effectiveness of oil extracts from Ageratum conyzoides L., Petiveria alliacea L., and Hyptis suaveolens L. as biopesticides against Sitophilus oryzae in the Entomology Laboratory of Federal University of Technology Akure, Ondo State. The experiments were conducted at a temperature of 28±2°C and a relative humidity of 75±5%. Methanol was used as a solvent to extract the oil from the plants, and different concentrations (0.5%, 1.0%, 1.5%, 2.0%, and 2.5%) of each plant extract were prepared. The results demonstrated that the oil extracts from all three plants had a significant impact on the mortality of Sitophilus oryzae. Among them, the oil extract from Hyptis suaveolens proved to be the most effective, causing 100% mortality of Sitophilus oryzae at 2.0% and 2.5% concentrations within 96 hours of introduction. The LD50 (concentration required to cause 50% mortality) for Hyptis suaveolens was 0.53 (at 96 hours) and 0.36 (at 120 hours), while the LD90 (concentration required to cause 90% mortality) was 4.27 (at 96 hours) and 1.86 (at 120 hours) for Sitophilus oryzae. Furthermore, the oil extracts of all three plants significantly reduced adult emergence of the insects and prevented weight loss in the seeds. These effects were particularly prominent at concentrations of 2.0% and 2.5%. Statistical analysis indicated significant differences (p < 0.05) between the treatments and control groups for all the parameters assessed. In conclusion, the results of this study demonstrated that the leaf extract of Hyptis suaveolens was more effective than the extracts from the other plants in reducing Sitophilus oryzae populations, inhibiting adult emergence, and preventing weight loss in stored grains. Therefore, Hyptis suaveolens can be considered as a valuable addition to the range of botanicals used for Sitophilus oryzae control in food storage.

Biorational potential of Mentha essential oils of Indian origin: Comparative note on insecticidal efficacy, fumigant persistence, oviposition deterrence of Sitophilus oryzae

Natural compounds have widely gained their acceptance as biorationals for management of storing grain from insect pests. Mentha spp. are commercially important plant genus known for its distinct aroma. The present study is aimed towards the comparative insecticidal activity of four mint essential oils (Mentha arvensis, Mentha citrata, Mentha piperita and Mentha spicata) against rice weevil (Sitophilus oryzae). Further, the GC-MS analysis of mint essential oil’s (EO’s) exhibited diversity in aroma compounds, M. arvensis (menthol 61% and l-menthone 9.11%), M. citrata (linalool 36.74% and linalyl acetate 35.9%), M. piperita (menthol 36.28%, menthone 26.37% and iso-menthone 5.15%) and M. spicata (54.14% of carvone and 20.97% of limonene). Whereas, the M. spicata EO exhibited the strongest toxicity (fumigant and contact) in both with and without food conditions around 100% mortality for 25 μL dose within 24 h of exposure. The LC50 and LD50 values exhibited by M. spicata were 54.07 μL/L and 11.5 μL/100 cm2 respectively. Similarly, the concentrations of 2.5% and 5% of M. spicata EO also exhibited a strong fumigant and contact toxicity against S. oryzae within 24 h as compared to known prophylactic insecticide (0.3% of Deltamethrin). Besides, 100% oviposition deterrence exhibited by all the four mint EO’s and 56% of AChE inhibition is noticed for M. spicata EO. Furthermore, post-treated grains showed no persistence of mint aroma residues and the treated grains retained the seed viability. Thus, on a comparative note, the M. spicata EO possess potential biorational traits for the effective management of stored grain from insect pests.

Mechanical properties and integrity of stored corn grains after continuous and intermittent drying

This study aimed to evaluate the influence of continuous and intermittent drying during the storage time on mechanical properties and integrity of corn. For intermittent drying, five rest times (0, 4, 8, 12, and 16 h) and four storage times (0, 90, 180, and 270 days) were used. The corn grains harvested at a moisture content of 0.34±0.001 kg kg-1 dry basis (db) were dried in a fixed-layer experimental dryer set at a temperature of 100 °C and an air flow rate of 1.5 m3 min-1 m-2 until they reached a moisture content of 0.16±0.03 kg kg-1 db. For intermittent drying, the process was interrupted at a moisture content of 0.22±0.02 kg kg-1 db and resumed after resting. Tests for electrical conductivity, rupture force, deformation, energy required for rupture, and modulus of toughness and hardness were conducted. Grain integrity is better maintained when the grain has been dried with a longer rest time and stored for short periods; compressive strength exhibits the same behavior as integrity, but hardness, energy for rupture, and the modulus of toughness are not influenced by storage time, and grain deformation was not affected by the rest and storage times.

Storage performance of non-waxy Japonica rice varieties preferred by Japanese consumers: Evaluation of physicochemical properties and in vitro starch digestibility

This study aimed to evaluate the changes during storage in the composition, texture, and starch digestibility of non-waxy Japonica rice varieties (cv. Yudai 21, Koshihikari, and Milky Queen) preferred by Japanese consumers. Stored grains were prepared by storing fresh grains at 30 °C for 6 months. Changes in pH of the rinse water and the color reaction of catalase activity showed a decrease in freshness and significant differences between varieties, between storage periods and by interaction. The total and resistant starch content decreased during storage and had significant correlations with pH and color reaction. Yudai 21 had higher surface adhesiveness, surface adhesion, and overall adhesiveness than Koshihikari with a similar apparent amylose (AA) content and Milky Queen with a lower AA content, regardless of storage. The equilibrium concentration of starch hydrolysis ranged from 84.1% to 94.9% with no significant difference and showed a significant correlation with pH (r = 0.78). The estimated glycemic index (eGI) was significantly affected by variety, with Koshihikari having the highest eGI and Yudai 21 having the lowest eGI, but was not affected by storage. Among the varieties, Yudai 21 was a suitable variety not only for fresh grains but also for stored grains, with high eating quality and low starch digestibility.

Survey on the Occurrence of Insect Pests in Stored Grains in Thiruvananthapuram District, Kerala State

To identify the species composition and relative abundance of insect pest in stored grains, a preliminary investigation was conducted by collecting grain samples from 16 grain merchant stores in Thiruvananthapuram District, Kerala state. Insect pest collected during the study were pulse beetle, Callosobruchus chinensis, cow pea beetle, C. maculatus, grain weevil, Sitophilus granarius, long headed flour beetle, Latheticus oryzae, rice weevil, Sitophilus oryzae, red flour beetle, Tribolium castaneum, lesser grain borer, Rhyzopertha dominica, saw toothed grain beetle, Oryzaephilus surinamensis, Angoumois grain moth, Sitotroga cerealella. Tribolium castanaeum, Sitophilus oryzae, Rhizopertha dominica (32.25%, 24.51%, 21.91% respectively per 200 g sample) were the most abundant pest species in the grain samples.

Medicinal Plants as a Natural Greener Biocontrol Approach to "The Grain Destructor" Maize Weevil (Sitophilus zeamais) Motschulsky.

According to the United Nations (UN), the global population may skyrocket to 9.8 billion people in 2050 and 11.2 billion in 2100, placing an overwhelming burden on food security as the world will have to meet this growing demand. Maize is the largest staple grain crop produced in developing countries. The maize weevil, Sitophilus zeamais, is one of the most destructive post-harvest pests of stored cereals and grains. The maize weevil contributes up to 40% of total food-grain losses during storage, mainly in developing countries. Current synthetic pesticides are ineffective, and, moreover, they raise serious environmental safety concerns as well as consumer health hazards. Drawing from past oversights and current environmental realities and projections, the global population has been switching to green living by developing sustainable strategies. In our context, these new greener strategies include the utilization of medicinal plants to control maize weevil infestation, which unlocks unlimited innovative possibilities, and, thus, improves the yield, quality, and safety of maize. Medicinal plants are less toxic, easily biodegradable, and capable of protecting grain from pests. This paper systematically outlines the literature on host plants as well as the feeding and associated diseases of the maize weevil. In light of this, we cement medicinal plants as excellent candidates in the pursuit of greener, sustainable, more potent, and cost-effective pesticides.

Toxicity and resistance levels of phosphine against Tribolium castaneum (Herbst) and Sitophilus oryzae (L.) populations

The most destructive stored grain pests in India are the rust red flour beetle and the rice weevil. The most common method for controlling these two pests in storage is phosphine fumigation. However, frequent and acute or chronic doses of exposure than the recommended doses lead to the development of genetic and morphological resistance by changing their traits towards phosphine.Our recent study aimed to detect phosphine resistance degreesin T. castaneum and S. oryzae populations from twelve locations in Odisha. According to bioassay analysis, for S. oryzae after 24 hrs exposure period forphosphine gas to all the assessed populations, the LC50 value varied from 0.004 mg/l to 0.038 mg/l and the population of one location i.e., Chhata (Kendrapara) was found to have strong resistance to phosphine with 9.50 fold more resistant in comparison with the laboratory population. The phosphine toxicity levels for T. castaneum ranged from the LC50 values of 0.130 mg/l (Kendupali, Barghar) to 0.011 mg/l (Durgapali, Sambalpur), i.e., they were 13.00 and 1.10 times more resistant than the laboratory-susceptible population. It is possible that increasing resistance levels is due to storage structures are not tightly sealed during fumigation leading to sub-lethal phosphine concentration and lack of knowledge about fumigation procedures.

Extraction and chemical characterisation of agro-waste from turmeric leaves as a source of bioactive essential oils with insecticidal and antioxidant activities

Turmeric (Curcuma longa L.) is a significant crop that has historically been used worldwide as a medicinal plant, spice, food colouring agent, and a significant ingredient in cosmetic industries. After harvesting rhizomes, leaves are considered waste material. This research study aims to extract and chemically characterise the essential oil from the leaves waste of turmeric with an evaluation of different insecticidal, antioxidant, and phytotoxic activities. Subsequently, the contact toxicity, fumigant toxicity, and repellent activity were evaluated against two key stored grain insect species. The gas chromatography-mass spectrometry (GC–MS) characterisation revealed that α-phellandrene (28.95%), 2-carene (16.51%), eucalyptol (10.54%) and terpinolene (10.24%) were the major chemical constituents. The study's findings on the insecticidal effects of essential oils extracted from turmeric leaves revealed noteworthy repellent, contact (at 24 h, LC50 = 6.51 mg/cm2 for Tribolium castaneum and LC50 = 4.74 mg/cm2 for Rhyzopertha dominica) and fumigant toxicities (at 24 h, LC50 = 2.57 mg/L air for T. castaneum and LC50 = 2.83 mg/L air for R. dominica), against two key stored grain insects. In addition, turmeric leaf essential oil showed notable antioxidant activity (IC50 = 10.04 ± 0.03 µg/mL for DPPH assay; IC50 = 14.12 ± 0.21 µg/mL for ABTS assay. Furthermore, a phytotoxicity study was carried out on stored paddy seeds and no toxic effects were found on germination rate and seedling growth. So, it might be expected that the essential oils extracted from the turmeric leaf waste could be valorised and demonstrate their potential as safe botanical insecticides against stored-product insects, with noble antioxidant properties.

Identification of Wolbachia pipientis and phylogenetic studies of plodia interpuntella populations in different cities of Pakistan

Wolbachiapipientis is genus of gram-negative bacteria which infect the members of phylum arthropoda, mainly affects the class insecta and some nematodes. Wolbachiapipientis are the common bacterial symbionts of the insects. About 25 to 70% of insect species are estimated to be the host of Wolbachiapipientis. Infection of these bacteria can alter the reproduction and biology of the host. Even some host species can not reproduce without Wolbachiapipientis infection. Due to thisreason, Wolbachiapipientis are used to control the population of pest species. A major reseach objective is the detection of Wolbachiapipientis in the Plodiainterpuntella populations of different cities of Pakistan leading towards its phylogenetic descriptions through molecular markers. Plodia interpuntella commonly called Indian meal moth. This insect is the major and most destructive pest of food grains such as, rice, maize and other cereals. The presence of this pest is relating with occurrence of such grains in homes and grocery stores. Indian meal moth feeding reduces the dry weight of stored grains. This study was done to estimates the economic and yield losses of food gains due to Plodia interpuntella in the different cities of Pakistain such as (Faisalabad, Jhang and Layyah) from Punjab, (Peshawar) from KPK and (Hyderabad) from Sindh. Firstly, the Collection of Plodiainterpunctella was completed from mention areas, and the pest was identified through morphologically, molecular analysis, eggs and larval instar. The results of our study showed that, the pest infection rate was ot similar in all the citites. Its majorly attack was identified in Faisalabd, Jhang, Layyah, Peshwar and Hyderabad gradually. During the study, pest infection rate was calculated in four months, July, August, September and October. The attack of pest was maximum in the start of July and minimum at the end of Octobor in stored grains. The results were calculated by using DNA extraction. The statistical analysis was performed through SPSS.

Impact of insect growth regulators on reproduction and life stages of Tribolium Castaneum (Coleoptera: Tenebrionidae)

Tribolium castaneum is devastating cosmopolitan insect pest of stored grain. The present study investigated the impact of three insect growth regulators on different life stages of T. castaneum. Percent mortality (%) induced was observed at 0.75. 1.25, 2.5, 5, 10, and 20 ppm doses of each IGR after 7, 14 and 21 day exposure. In addition to larval and parental mortality, progeny suppression data was also recorded. The larvae of the 2nd instar were more susceptible to lufenuron, with mortality reaching 100% at 10ppm even after a 14-day interval. In the case of pyriproxifen, 2nd instar did not responded to all dose rates until 14 days however 21 days, statistically corresponding 2.5 to 10 ppm dose rates was detected. At 20 ppm, methoxy fenazide resulted in 92 percent mortality of 2nd larval instar mortality, and the larvae responded to all dose rates at all exposure intervals that varied significantly among themselves. The mean mortality of the 4th instar larvae at 20 ppm for lufenuron after a 21-day interval was 90%, which was not significantly different from the mortalities (62 and 80%) at the same dose rate after 7 and 14 days, respectively. All the IGRs were very effective in progeny suppression (>80%) and complete progeny suppression (100%) was observed in adults treated with methoxyfenazide and lufenuron at 2.5 and 10 ppm doses, respectively. It is concluded that all the screened IGRs were effective in progeny suppression and in some cases, complete progeny suppression was achieved

Detection of Specific Volatile Organic Compounds in Tribolium castaneum (Herbst) by Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry

The red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), is a major storage pest that could lead to a wide range of damage. Its secretions have a significant impact on the quality of stored grain and food, leading to serious food safety problems such as grain spoilage and food carcinogenesis. This study investigates new detection techniques for grain storage pests to improve grain insect detection in China. The primary volatile organic chemicals (VOCs) in these secretions are identified using headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). The specific VOCs that are unique to T. castaneum are selected as criteria for determining the presence of T. castaneum in the granary. To obtain more specific VOCs, experiments were designed for the analysis of T. castaneum samples under different extraction times, two types of SPME fibers and two GC-MS devices of different manufacturers. The experimental results showed that 12 VOCs were detected at relatively high levels, seven of which were common and which were not detected in other grains and grain insects. The seven compounds are 1-pentadecene, 2-methyl-p-benzoquinone, 2-ethyl-p-benzoquinone, 1-hexadecene, cis-9-tetradecen-1-ol, m-cresol and paeonol. These seven compounds can be used as volatile markers to identify the presence of T. castaneum, which could serve as a research foundation for the creation of new techniques for T. castaneum monitoring.

Comparison of phenotypic and genotypic frequency of phosphine resistance in select field populations of Tribolium castaneum from India.

Tribolium castaneum causes substantial damage to stored grains, leading to economic losses. The present study evaluates phosphine resistance in adult and larval stages of T. castaneum from north and northeast India, where continuous and long-term phosphine use in large-scale storage conditions intensifies resistance, posing risks to grain quality, safety, and industry profitability. This study utilized T. castaneum bioassays and CAPS markers restriction digestion methodology to assess resistance. The phenotypic results indicated a lower LC50 value in larvae compared to adults, while the resistance ratio remained consistent across both stages. Similarly, the genotypic analysis revealed comparable resistance levels regardless of the developmental stage. We categorized the freshly collected populations based on resistance ratios, with Shillong showing weak resistance, Delhi and Sonipat displaying moderate resistance, and Karnal, Hapur, Moga, and Patiala exhibiting strong resistance to phosphine. Further validation by accessing findings and exploring the relationship between phenotypic and genotypic variations using Principal Component Analysis (PCA). This comprehensive study enhances our understanding of T. castaneum resistance levels, providing valuable insights for the development of targeted pest management strategies. This study provides insights into the current phenotypic and genotypic resistance levels of T. castaneum in North and North East India. Understanding this is crucial for developing effective pest management strategies and future research on biological and physiological aspects of phosphine resistance in insects, enabling the formulation of effective management practices. Addressing phosphine resistance is vital for sustainable pest management and the long-term viability of the agricultural and food industries.

ACTIVITY OF PLANT ESSENTIAL OILS AGAINST OCHRATOXIN A PRODUCING ASPERGILLUS OCHRACEUS

Plant essential oils have been used in traditional medicines since ancient times to combat disease and in agro-food science to preserve food stuff. Antifungal activity of plant essential oils was evaluated using different substrates of varied moisture levels against ochratoxin A (OTA) producing Aspergillus ochraceus. A. ochraceus (n = 3) isolates were processed for antifungal activity of various essential oils including Zingiber officinale, Curcuma longa, Eucalyptus globulus, Syzygium aromaticum, Nigella sativa, Elettaria cardamomum, Cinnamomum verum and Cuminum cyminum extracted by hydro-distillation. To check the antimicrobial activity of essential oils, the highest zone of inhibition recorded was of C. verum (33.67±0.57mm) followed by S. aromaticum (30.33±0.57mm) and the least minimum inhibitory concentration (MIC) was of S. aromaticum (0.52±0.22 µg/mL) followed by C. verum (0.65±0.22 µg/mL). Antifungal activity was evaluated in term of log reduction and at the exposure time of 60 and 90 min, 6±0.00 log reduction was observed by S. aromaticum, C. verum and E. cardamomum with non-significant differences. At 15th, 30th, 45th and 60th day of experiment, toxin production by A. ochraceus at moisture contents (10, 20, 30, 40, 50, 60 and 70%) in un-inoculated groups and inoculated treated groups with C. verum Essential Oils were found non-significantly different to each other but significantly different from the OTA production in inoculated groups of wheat, maize and rice (intact and broken). At 10% moisture level, OTA production was low and reached to maximum level at 40% moisture level and again decline with increasing moisture level. Cinnamon has showed antifungal activity against A. ochraceus at all moisture levels. The confirmation of inhibition potential of C. verum was evaluated using thin layer chromatography (TLC) and high-performance liquid chromatography (HPLC) techniques. This study illustrates that cinnamon oil is effective to inhibit the growth of OTA producing A. ochraceus in stored grains to overcome the economic losses. Keywords: Antifungal activity, Cinnamomum verum, Dimethyl sulfoxide, Log reduction, Minimum inhibitory concentration

Pulegone, a component of Schizonepeta tenuifolia volatiles can act as an effective fumigant of the rusty grain beetle Cryptolestes ferrugineus

The utilization of new plant-based fumigants is one of the most important green control methods for safe storage and protection of grain. The rusty grain beetle, Cryptolestes ferrugineus (Stephens) (Coleoptera: Laemophloeidae), is a common stored grain pest that causes a great loss of stored grain every year. This study determined that, Schizonepeta tenuifolia Briq. spike (SS) powder had strong fumigant insecticidal effectiveness against C. ferrugineus. Moreover, the volatile eluates (VEs) of SS extracted with Porapak™ Q adsorbent at a flow rate of 600 mL/min exhibited higher insecticidal activity against C. ferrugineus adults than the larvae; the VEs LC50 of C. ferrugineus adults were 14.93%− 24.83% of those of C. ferrugineus larvae. The temperature, not the age of C. ferrugineus adults, significantly influenced the fumigation effect of SS VEs; at relatively low temperature (15 ℃) the SS VEs showed quicker and more efficient fumigant activity than at a high temperature (30–35 ℃). In addition, S. tenuifolia VEs showed better fumigation effects against Oryzaephilus surinamensis (Coleoptera: Silvanidae) and Sitophilus oryzae (Coleoptera: Curculionidae) compared to Tribolium castaneum (Coleoptera: Tenebrionidae). The four most abundant components of SS volatiles analyzed by GC-MS were pulegone (62.62%), isomenthone (18.34%), 2-isopropyl-2,5-dimethylcyclohexanone (2.45%), and isopulegone (1.32%), in order by their peak area ratio. Toxicity testing of the two compounds with the largest proportion indicated that only pulegone had insecticidal activity against C. ferrugineus adults with a LC50 (8.90 mL/L) at 72 h. Consistent with VEs, temperature also greatly affect the fumigant activity of pulegone and at low temperature (15 ℃) the pulegone showed more quick and effective insecticidal activity against C. ferrugineus adults. We further found that both VEs and pulegone can inhibit carboxylesterase (CarE), peroxidase (POD), and superoxide dismutase (SOD) in vivo and in vitro, especially the inhibition rate of carboxylesterase, which reached 84.87% and 63.82% at 24 h in vivo, which suggested that the fumigant insecticidal activity of SS VEs and pulegone may partly be mediated by affecting the detoxification and metabolism enzyme system of C. ferrugineus. Therefore, both S. tenuifolia and pulegone can be used as botanical fumigant to potentially control stored grain pests.

Age Specific and Fertility Lifetable of <i>Callosobruchus Maculatus</i>(F.) on Chickpea

Pulse beetle (Callosobruchus maculatus) (F.) is a pernicious pest of different stored grain pulses and decrease the nutritional and economic values of the pulses, which can cause huge losses in terms of quality and quantity. The present study was conducted for determining the rate of multiplication of C. maculatus was conducted at ambient temperature and relative humidity under Palampur conditions on preferred host chickpea, Cicer arietinum. Under conditions of abundant space and food supply, population of C. maculatus increased with 0.03485 (r m ) and 1.035 (λ) per day. The population multiplied 1.276 times in one week and mean time for doubling the population was 19.88 days. True generation time was 63.07 days. Life expectancy of adult was 12.37 days. The results of the study pave ways to create awareness among researchers and farmers about the nature and extent of damage caused by the C. maculatesin chickpea.

Review on Post-Harvest Grain Treatments (Filter Cake, Triplex Powders and Eucalyptus Tree Powder)

Grains are harvested seed and edible dry seeds from plants cereals. They are the basis of daily diets for many populations worldwide. In addition, they are fundamental in the regular foods of many people and used for the production of different popular food. Grain losses due to insect pests in sub-Saharan Africa especially in Ethiopia are very high. Therefore, to get those daily diets and reduce loss occurred by insects, treatment of grain is very important. The objective of this review is to review studies made by various researchers and reviewers on grain treatments (filter cakes, triplex and powder eucalyptus tree leaves). Application of chemical pesticides is important to protect stored grain from insect pests. However, most of smallholder farmers challenged with many problems related to unsafe handling and use of pesticides due to improper training in safe use of pesticides, and inadequate infrastructure to regulate safe use of pesticides. Filter cake and Triplex powders applied to different grains to determine effectiveness against the grains. Filter cake is products of aluminum sulfate and Triplex is products of soap factories. Defense of stored grain from insect pests using Filter cake, Triplex powders and eucalyptus leaves tree has been practiced in Ethiopia. Filter cake and Triplex have a higher atomic percentage of silicon and oxygen in the form of silicon dioxide. Generally, grain treatment is very important through filter cake and triplex as well as by using eucalyptus tree powder, due to they have properties of toxic against insects and no health problems on humans. Therefore, Filter cake Triplex and eucalyptus leave recommended for protecting and managing grain stored by smallholder farmers in Ethiopia to discourage farmers from using dangerous chemical insecticides.

Quick knockdown results in high mortality: is this theory correct? A case study with phosphine and the red flour beetle.

The fumigant phosphine is used all over the world for disinfestation of stored grains and commodities. Adults of 23 different populations of Tribolium castaneum from 10 different countries were evaluated for phosphine resistance using a modification of the Detia Degesch Phosphine Tolerance Test Kit (DDPTTK). Adults were exposed to 3000 ppm and recorded for 5-270 min for their mobility. Among the tested populations, high levels of phosphine resistance were recorded in populations from Brazil, Serbia, and Spain. No survivals were recorded after 7 days post exposure for eight of 23 in a tested population. Our work revealed four scenarios: 1, quick knockdown-low (or no) recovery; 2, Slow knockdown-high recovery; 3, Quick knockdown-high recovery; and 4, Slow knockdown-low recovery. Our data indicate that post exposure period is critical for the evaluation and characterization of phosphine resistance. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.