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Hermetic storage technology using plastic liners is threatened by the boring action of Prostephanus truncatus Horn. (Coleoptera: Bostrichidae), a major insect pest of stored maize in sub-Saharan Africa. We investigated the performance of four brands of hermetic storage bags against adult P. truncatus in maize stored for 90 d under simulated resident and incoming infestation. Five treatments were used: four hermetic bag brands; SuperGrain Bag (SGB) IV-R, SGB Farm, Purdue Improved Crop Storage (PICS) bag, and Kuraray bag; and an ordinary plastic bag; each containing 50 kg of shelled maize. Two modes of insect infestation were used whereby 50 adult insects were introduced inside and outside the hermetic bags to simulate resident and incoming insect infestations, respectively. Parameters measured included carbon dioxide–oxygen levels, live adult P. truncatus numbers, grain moisture content, grain damage and weight loss, germination, and number of insect-induced perforations on plastic liners. Externally infested bags had no insect activity; all the introduced insects died of starvation. Internally infested bags were all perforated. The ordinary plastic liner was severely perforated with 151 insect-induced holes compared to hermetic plastic liners (<40 holes).There was no live adult insect infestation in grain samples collected using double-tube multi-slotted sampling probes inserted vertically several times. However, live adult insects were present in the bottom grain layer (0.05 m) of all plastic liners. There were no significant differences between hermetic bags regardless of mode of infestation for all parameters assessed. The results show that the tested hermetic bags are equally susceptible to perforations by resident P. truncatus.

Understanding rodent seed caching behavior is critical for effective forest management and conservation. While it is well established that rodent feeding behavior is strongly affected by seed traits and insect infestation of seeds, there is still a knowledge gap on how these factors affect rodent feeding behavior. Here we conducted a series of experiments to investigate the feeding and hoarding preferences of two sympatric rodent species, the Chinese white-bellied rat (Niviventer confucianus) and South China field mouse (Apodemus draco) in response to Chinese chestnuts (Castanea mollissima) of contrasting seed size and insect infestation. When only sound nuts (not infested nuts) were provided, both species preferentially consumed larger nuts, esp. the larger N. confucianus showed more pronounced selective preference for larger nuts than the smaller A. draco. When sound and insect-infested nuts of equal size were provided, neither species selected for sound over insect-infested nuts, but infested seeds were more frequently consumed in situ. If nuts of differing size and infestation status were provided, rodents preferred to eat and hoard larger seeds regardless of insect infestation. Overall, however, infested seeds were more often consumed immediately in situ while sound seeds were more often consumed ex situ or cached. Our results thus support the seed size hypothesis, but show little evidence for the insect infestation hypothesis, and highlight that food preferences and optimal foraging decisions differ between sympatric rodent species.Significance statementRodent caching and feeding behaviors are strongly affected by co-varying seed traits such as size and insect infestation, which in turn regulate seed survival and seedling recruitment. By using semi-natural enclosures, we detected differences in feeding and hoarding behaviors between sympatric rodent species, and their different preferences for seed size and insect infestation. These different preferences may support the seed size hypothesis. Rodents based their foraging decision predominantly on seed size and not insect infestation, preferring to eat and hoard larger seeds regardless of their insect infestation. We suggest that the differences in feeding and hoarding behaviors of sympatric rodent species in relation to seed size and insect infestation should be considered in future field studies, as this will help us to better understand mechanisms that impact forest management and conservation.

The southern boreal forests of North America are susceptible to large changes in composition as temperate forests or grasslands may replace them as the climate warms. A number of mechanisms for this have been shown to occur in recent years: (1) Gradual replacement of boreal trees by temperate trees through gap dynamics; (2) Sudden replacement of boreal overstory trees after gradual understory invasion by temperate tree species; (3) Trophic cascades causing delayed invasion by temperate species, followed by moderately sudden change from boreal to temperate forest; (4) Wind and/or hail storms removing large swaths of boreal forest and suddenly releasing temperate understory trees; (4) Compound disturbances: wind and fire combination; (5) Long, warm summers and increased drought stress; (6) Insect infestation due to lack of extreme winter cold; (7) Phenological disturbance, due to early springs, that has the potential to kill enormous swaths of coniferous boreal forest within a few years. Although most models project gradual change from boreal forest to temperate forest or savanna, most of these mechanisms have the capability to transform large swaths (size range tens to millions of square kilometers) of boreal forest to other vegetation types during the 21st century. Therefore, many surprises are likely to occur in the southern boreal forest over the next century, with major impacts on forest productivity, ecosystem services, and wildlife habitat.

Experiments were undertaken to estimate the yield losses due to Maruca vitrata (Fabricius) in kharif mungbean at Pulses Research Farm, Punjab Agricultural University, Ludhiana and Krishi Vigyan Kendra, Bahowal, Hoshiarpur during kharif 2022. The yield losses were estimated using insect-infestation and chemical protection method in the recommended variety of mungbean, ML 1808. In insect-infestation method, at both the locations, the mean number of webs produced per plant after 5 days of insect infestation during first release and second release and pod damage were significantly lower in the infested treatment in comparison to the uninfested treatment. The yield losses were determined to be 21.93 per cent and 21.56 per cent at Ludhiana and Hoshiarpur, respectively using this method. The outcome of chemical protection method at both the locations revealed that the mean number of larvae and webs per plant in the protected plots were significantly lower than unprotected plots after three and five days of two insecticide sprays. Pod damage was significantly higher in the unprotected plots than protected plots at both the locations. The yield losses were determined to be 21.30 per cent and 21.91 per cent in Ludhiana and Hoshiarpur, respectively using chemical protection method. Such estimated yield losses can ultimately be linked to the production factors to identify opportunities for remedial actions that farmers can implement to reduce losses. This study’s experimental methods could be used to evaluate yield losses in other crops as well.

Most packaged food products are attacked and penetrated by insects. Causing reducing food quality. Since, different ways are investigated for controlling stored-product pests without application of chemical methods. So, the present study included laboratory methods to evaluate the effectiveness of two packaging materials, polyethylene and cellophane with silica nano particles to prevent or minimize the insect infestation and grain wastage resulting by the attack of wheat grain by confused flour beetle, Tribolium confusum . Studies made to determine the protecting capacity of the two packaging materials through assessing some parameters, number of adults infested poly ethelene and cellophane bags, percentage weight loss of grains, the results revealed that cellophane was the better packaging material than polyethelene, so polyethylene was the susceptible packaging material because it had maximum number of holes as a result penetrations by insects into them. Also, treatment the two types with packaging materials with different concentrations of nano silica protect the treated packaging materials from insect infestation and the protection increase with the increase of the concentration of silica nano particles

Insect meal is a new agricultural commodity that will be produced in huge quantities in the near future and will be treated as all traditional agricultural commodities, i.e., insects will be harvested, processed, transported and stored. As most agricultural commodities, insect meals may be prone to insect infestations during their “post-harvest stages.” However, no information is available at the moment on the susceptibility of insect meals to stored-product insect infestations. The objective of the present study was to evaluate the susceptibility of Tenebrio molitor larvae-meal to insect infestations during storage. Specifically, we investigated the population growth of major stored-product insects, i.e., T. molitor , Tribolium confusum , Alphitobius diaperinus and Trogoderma granarium on T. molitor larvae-meal, as well as on T. molitor meal-based substrates with different percentages of wheat bran (0, 25, 50, 75, 90, 95 and 100%). Our results show that T. molitor and T. confusum can infest 100% T. molitor meal and develop significant populations on this substrate. However, the speed of growth of both species in 100% T. molitor meal was considerably lower compared to the substrates that contained also wheat bran. In contrast, A. diaperinus and T. granarium did not grow at all on 100% T. molitor meal and both exhibited poor growth on the substrate containing 75% insect meal. In general, our results show the susceptibility of T. molitor larvae meal, as well as T. molitor meal-based substrates with different percentages of wheat bran, to infestations by major stored-product insects. To our knowledge, this is the first study on the susceptibility of insect meals to insect infestations.

Japanese chestnut ( Castanea crenata Sieb. et Zucc.) has a long juvenile phase, so breeders have to wait many years to evaluate nut traits. Molecular markers associated with genes of interest would accelerate selection in chestnut breeding programs. We evaluated five nut traits (nut harvest date, nut weight, pericarp splitting, insect infestation, and specific gravity) in 99 Japanese chestnut cultivars and selections. A wide range of phenotypic variation was observed for each of the traits, suggesting that the collection harbored sufficient genetic diversity for breeding. A Bayesian genome-wide association study was conducted using 162 simple sequence repeat markers and 741 single nucleotide polymorphism markers. To evaluate the potential of marker-assisted selection, we examined 12 molecular markers found to be associated with nut traits: 4 for nut harvest date, 4 for nut weight, 1 for pericarp splitting, and 3 for insect infestation. The percentages of phenotypic variance explained ranged from 4.8 to 37.1%. Although insect infestation showed only medium heritability (0.672), we obtained two quantitative trait loci (QTLs) with extremely high posterior probabilities (0.93 and 1.00). Out of the 12 molecular markers, 3 of the 4 markers for nut harvest time could be validated in a breeding population. Accuracies of genomic selection were extremely high for nut harvest date (0.841) and moderate for insect infestation (0.604), suggesting that genomic selection based on Bayesian regression would reduce the cost of phenotypic evaluation of these traits and possibly others.

The feasibility of non-destructive detection and classification of in-shell insect-infested almonds was examined by using multispectral imaging (MSI) technology combined with chemometrics. Differentiation of reflectance spectral data between intact and insect-infested almonds was attempted by using analytical approaches based on principal component analysis and support vector machines, classification accuracy rates as high as 99.1% in the calibration set and 97.5% in the prediction set were achieved. Meanwhile, the in-shell almonds were categorized into three classes (intact, slightly infested and severely infested) based on the degree of damage caused by insect infestation and were characterized quantitatively by the analysis of shell/kernel weight ratio. A three-class model for the identification of intact, slightly infested and severely infested almonds yielded acceptable classification performance (95.6% accuracy in the calibration set and 93.3% in the prediction set). These results revealed that MSI technology combined with chemometrics may be a promising approach for the non-destructive detection of hidden insect damage in almonds and could be used for industrial applications.

The influence of packaging materials on infestation by Tribolium castaneum (Herbst) in wheat flour was investigated under laboratory conditions at 27 ± 2and 75 ± 5% relative humidity. The tested packaging materials included vacuum-sealed plastic bags, aluminum foil bags, non-woven cloth bags, kraft paper bags, and plastic compound bags. When T. castaneum adults were released on packaged wheat flour, the degree of infestation varied depending on the packaging materials. The highest infestation was observed in refined wheat flour packaged with plastic compound bags (mean 46 ± 20 insects). For the flour packaged with non-woven cloth bag and kraft paper bags exposed to adults, insect infestation was nil or negligible (mean population < 3 ± 1 insects). For the flour packaged with aluminum foil bags and vacuum-sealed plastic bags exposed to adults, insect infestation was nil. Damage to the packaging materials along the edges or on the upper surfaces was observed in non-woven cloth bags and plastic compound bags. Aluminum foil bags and vacuum-sealed plastic bags offered the best protection against T. castaneum adults.

The interactions of vector–virus–plant have important ecological and evolutionary implications. While the tripartite interactions have received some attention, little is known about whether vector infestation affects subsequent viral transmission and infection. Working with the whitefly Bemisia tabaci, begomovirus and tobacco/tomato, we demonstrate that pre-infestation of plants by the whitefly vector reduced subsequent plant susceptibility to viral transmission. Pre-infestation by the cotton bollworm, a nonvector of the virus, likewise repressed subsequent viral transmission. The two types of insects, with piercing and chewing mouthparts, respectively, activated different plant signaling pathways in the interactions. Whitefly pre-infestation activated the salicylic acid (SA) signaling pathway, leading to deposition of callose that inhibited begomovirus replication/movement. Although cotton bollworm infestation elicited the jasmonic acid (JA) defense pathway and was beneficial to virus replication, the pre-infested plants repelled whiteflies from feeding and so decreased virus transmission. Experiments using a pharmaceutical approach with plant hormones or a genetic approach using hormone transgenic or mutant plants further showed that SA played a negative but JA played a positive role in begomovirus infection. These novel findings indicate that both vector and nonvector insect feeding of a plant may have substantial negative consequences for ensuing viral transmission and infection.