Insect Pests Of Maize Research Articles

Postharvest Practices and Farmers' Knowledge in Managing Maize Pests in the Eastern Cape Province, South Africa.

This study aims to establish the pest management approach for pests of stored maize and determine the current control practices. Semi-structured questionnaires were administered to 77 smallholder farmers from 16 villages at King Sabata Dalindyebo local municipality in the Eastern Cape Province of South Africa. The results revealed that about 50% of the farmers had a formal education, the average farm size was 1 hectare, and they were predominantly cultivating yellow maize. Most farmers (57%) cultivated maize for human consumption, income generation, and livestock feeding. The results also showed that metal tanks tended to be the most preferred (81.82%) storage facility for storing maize. Furthermore, the study found that Sitophilus zeamais Motschulsky and Sitotroga cerealella (Olivier) were the major storage insect pests of maize. The storage pests were managed using synthetic pesticides (84.42%), namely aluminium phosphide. This pesticide is a solid formulation for generating gas phosphine for fumigation. The continued indiscriminate use of this pesticide in protecting stored maize in this region could be a health hazard to humans and may result in the development of pest resistance.

Adult Anomala denuda arrow 1819 (Coleoptera: Scarabaeidae) as nocturnal insect pest of maize in Côte d’Ivoire

Adult Anomala denuda arrow 1819 (Coleoptera: Scarabaeidae) as nocturnal insect pest of maize in Côte d’Ivoire

Farmers Survey to Assess of Yield Loss due to Insect Pests in Maize and their Management Strategies Adopted by Farmers of Baitadi District of Nepal

The loss due to insect-pests is one of the major constraints in crop cultivation. In order to assess the losses due to insect pests, a survey was conducted in Dashrath Chand municipality and Surnaya Rural Municipality of Baitadi district under Prime Minister Agriculture Modernization Project (PMAMP), Maize Zone, Baitadi. A total of 100 household heads were selected among the farmers of maize pocket areas of the Prime Minister Agriculture Modernization Project for interview using a semi-structured questionnaire. The descriptive and comparative analysis was done for the field survey data using Microsoft Excel (MS Excel), and ranking the problems using the Wilcoxon signed rank test using statistical tools Statistical Packages for the Social Sciences (SPSS). Additionally, indexing was used to rank the major insect pests found in the maize field. Results showed that the major problematic insects found in the maize field were fall armyworm (Spodoptera frugiperda), cutworm (Agrotis spp.), maize stem borer (Chilo partellus) and white grub (Phyllophaga spp.) respectively, as ranked by the farmers according to losses caused by them. The indexing identified fall armyworm infestation as the most crucial problem with an index value of 0.85 (I=0.85). Interestingly, the maximum loss was found 37.5% (local variety) and the minimum loss 8.33% (hybrid variety). Farmers responded that the average loss caused by the insect in local and improved varieties was 25.19% and 18.38%, respectively. Thus, it can be concluded that comparatively the local varieties are more affected by insect pests than the improved varieties. All the surveyed farmers were found to be practicing both the physical and cultural methods. However, some farmers (10%) were also found to be using biological method of insect control. None of the farmers in the selected areas were found to be using chemical pesticides. So this research is focused on identifying damage and various management practices that can be adopted to solve the yield loss caused by insect pests.

Intercropping in maize reduces fall armyworm Spodoptera frugiperda (J. E. Smith) infestation, supports natural enemies, and enhances yield

Fall armyworm (FAW) is a multi-generational invasive insect pest of maize. Field experiments were conducted in diverse ecologies at Hyderabad, Telangana (Location 1); Dholi, Bihar (Location 2); Kolhapur, Maharashtra (Location 3) during the rainy season from July-November, 2023 to assess the impact of maize intercropping with legumes and leafy vegetables on FAW damage, abundance of beneficial insects, weed dynamics, and yield. In the present study, location-specific intercrops were selected for the experimentation. In location 1, maize intercropped with cowpea followed by groundnut reduced the level of FAW infestation compared to sole maize. The increased natural enemy population (coccinellids, spiders, earwigs); weed suppression, and higher yields were observed in maize when intercropped with cowpea followed by groundnut and red amaranthus. In location 2, maize intercropped with cowpea followed by green gram and black gram reduced the FAW damage and higher natural enemy population. Maximum yield was obtained in maize intercropped with black gram followed by green gram and cowpea. However, concerning weed suppression and cost-benefit ratio, green gram followed by black gram was found to be superior. Minimum FAW infestation, abundant natural enemy population, weed suppression, and improved economic returns were observed in maize when intercropped with cowpea followed by groundnut and fenugreek in location 3. Each intercrop had its advantages concerning pests, weed suppression, an abundance of natural enemy populations, and higher yields. Therefore, it is suggested that the selection of plants as intercrops with maize should be based on the location-specific importance of particular aspects to attain multifunctional benefits. The present results revealed that crop diversification with location-specific intercrops can reduce significant yield losses caused by FAW and promote higher yields in maize.

Philippine Traditional Maize with Resistance to Asian Corn Borer [Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae)] Leaf and Stalk Feeding Damage

Maize has been identified as an excellent alternative to rice as a staple food in the Philippines. The Asian corn borer (ACB; Ostrinia furnacalis Guenée), one of the most destructive insect pests of maize, damages plants throughout their vegetative and reproductive stages. Most open-pollinated varieties are threatened by pests and diseases. The CGUARD program investigated the potential of traditional Philippine maize as a source of resistance to major insect pests, including ACB. This paper evaluated the response of the selected 149 Philippine traditional maize accessions to ACB at vegetative and reproductive stages through laboratory bioefficacy procedures for potential resistance without the presence of Bt leaf and stalk-feeding resistance were determined through mean larval survival and mean tunnel length, respectively, after 5 d using laboratory- reared second-instar larvae. Improvements in screening procedures for laboratory assays are detailed in this report. Fourteen (14) accessions were identified to have promising leaf-feeding resistance, whereas 30 accessions were identified for stalk-feeding resistance. The resistance of APN 0088, a white glutinous type of maize from Palawan, to both leaf and stalk feeding of ACB was also validated. The results demonstrate the presence of natural resistance to ACB in traditional maize that has been exposed to the threat of the pest for decades. These promising accessions may be utilized to generate ACB-resistant or-tolerant maize, in addition to other breeding programs. Several pigmented varieties with ACB resistance were also identified, which may be further examined for their nutritional properties and potential as functional foods. By utilizing our traditional varieties, we are boosting local maize production that will benefit small-scale farmers and ultimately providing them with a high-performing variety that is crucial in this time of changing climate.

Comparative Study of Synthetic Insecticides with Biopesticides against Spotted Stem Borer, Chilo partellus (Swinhoe) on Maize (Zea mays L.)

Spotted stem borer, Chilo partellus (Lepidoptera: Pyralidae) regarded as one of the most significant and prevalent insect pests of maize and its mystic aspect of feeding makes it challenging to control. Hence current study aims to evaluate comparative study of synthetic insecticides with biopesticides against Chilo partellus. Eight treatments viz., azadirachtin 10,000ppm, neem oil 3%, karanj oil 3%, neem oil 3% + imidacloprid 17.5%SL, karanj oil 3% + imidacloprid 17.5%SL, imidacloprid 17.5%SL, spinosad 45%SC and untreated control were tested under field condition in randomized block design with three replications. Among the treatments, lowest larval population of Chilo partellus per plant were recorded in karanj oil 3% + imidacloprid 17.5%SL (1.99) followed by neem oil 3% + imidacloprid 17.5%SL (2.42), imidacloprid 17.5%SL (2.71), spinosad 45%SC (3.17), neem oil 3% (3.73), karanj oil 3% (3.95) and azadirachtin 10,000ppm (4.44) were found superior over the untreated control (7.24). The highest yield was recorded in karanj oil 3% + imidacloprid 17.5%SL with 39.20 q/hectare and most economic treatment was imidacloprid 17.5%SL with highest cost benefit ratio (1:2.2). The lowest cost benefit ratio was recorded in untreated control (1:1.4).

Comparative analysis of knowledge and management practices of insect pests of maize among IPM adopters and non-adopters in Sindhupalchok, Nepal

Integrated pest management (IPM) is a decision-based approach that involves optimizing the pest population below the economic threshold by the coordinated use of multiple tactics in an economically and environmentally sound manner. The adoption of IPM in farming practices prevents long-term pest damage by combining biological control, modification of cultural practices, habitual manipulation, and use of resistant varieties. In Nepal, mostly in hilly regions, haphazard chemical pesticide application has inevitable effects on human health, the environment, and the ecosystem. The haphazard chemical pesticide application in Sindhupalchok, Nepal originated mostly due to a knowledge gap in the identification of the stages of the lifecycle of pests, and the distinction between beneficial and harmful insects. To compare the effectiveness of management practices between IPM adopters and non-adopters this study was framed for six months in Sangachokgadi municipality, Sindhupalchok, Nepal. The knowledge gap among the maize growers in Sindhupalchok was assessed using both primary and secondary data collection methods. For primary data collection a comprehensive and structured questionnaire, face-to-face interview, phone call interview, and Key Informant Interview was conducted. Similarly, secondary data was collected from various articles and publications from Maize Zone, the Ministry of Agriculture and Livestock Development (MoALD), Nepal Agriculture Research Council (NARC), and National Maize Research Program (NMRP). The collected data were then analyzed (descriptive statistics, chi-square test, and indexing) by using computer software packages i.e., Statistical Package for Social Science (SPSS) version 26, and Microsoft Excel 2010. The analyzed data revealed maize growers adopting IPM practices for crop management are known to have significantly better knowledge of the life cycle of pests, were able to distinguish between beneficial and harmful insects, and had knowledge of appropriate fertilizer doses. Further, the findings revealed IPM adopters had better knowledge of chemical pesticide handling which could minimize the chemical hazards among the farmers.

Mechanical stirring of bulk-stored maize in steel bins to suppress maize weevils and other beetle populations

This study investigates the effectiveness of periodic stirring as a non-chemical approach to suppress maize weevils, Sitophilus zeamais, and other beetle populations in large-scale grain storage bins. The research was conducted in a farm steel bin with a diameter of 9.8 m holding 127 Mg of maize, and a control bin of diameter 7.3 m holding 102 Mg of maize. Both bins were loaded with maize at 13% moisture and infested at a commercial tolerance rate of 2 weevils/kg of maize. Probe traps monitored beetle populations except for S. zeamais before stirring was initiated. Maize samples were collected at depths of 0, 0.9, 1.8 and 2.7 m with a vacuum-probe sampler prior to stirring and at 10, 20, 30 and 40 days of continuous stirring machine operation. Stirring achieved 100% control of live S. zeamais while the control bin experienced an increase in its S. zeamais population after 40 days. The stirring process also led to a significant reduction in dominant beetle populations such as hairy fungus beetles, Typhaea stercorea, and foreign grain beetles, Ahasuerus advena. Although the quality of maize in both bins changed at different depths and storage times, the treatment bin had higher bulk density (732.7 ± 3.98 kg/m3 to 768.9 ± 2.41 kg/m3), lower insect damage (0.02 ± 0.02% to 0.9 ± 0.28%), and higher allowable storage time (>249 days). Moisture content and molded kernels increased in the control bin, reaching 26.4 ± 1.29% and 3.2 ± 0.53%, respectively. The average percentage of broken corn and foreign material (BCFM) in the sweepings on the floor of the emptied treatment bin was 6.5 times higher than that in the control bin. Calculated packing factor values below 1.5 from the sweepings indicated that BCFM concentrations did not affect airflow. Stirring maize provides an alternative to the use of chemicals to control stored maize insect pests at a production scale.

Particle Size Effect of Piper guineense in the Control of the ‘Sitophilus zeamais Motchulski’ on Maize

Sitophilus zeamais is perhaps the most important storage insect pest of maize. The negative health implication of synthetic pesticides necessitates research into botanicals. We investigated the efficacy of ground Piper guineense (particles sizes 150, 300, 600, 1180, and 2360 µm) in controlling S. zeamais. The botanicals were compared with pirimorphos methyl and control (untreated seeds). Completely Randomized Design was used with three replications. Each treatment was infested with 20 adult weevils. Weevils were withdrawn after 14 days and the experiment was observed for another 38 days to count emerged adult weevils, numbers of damaged grains and exit holes on seeds, and determine loss in seed weight. Progressive efficacy and significant differences were observed among the botanicals and Pirimorphos methyl from four days after treatment application (DAT) to 14 DAT (90%, 100%, 100%, and 46.67%for Pirimorphos methyl, 150, 300, and 2360 µm of Piper respectively) as the particle size decreases. Piper of 150 and 300 µm particle sizes produced no new adult weevil and no seed weight loss at 52 DAW compared to others. The efficacy of piper at different particle sizes from 4 DAT showed that graduating piper particle size has significant effects on its insecticidal activity. It was concluded that ground piper of particle size 150µm is the most effective and is therefore recommended for effective control of maize weevils in storage.

Population Fluctuations of Fall Armyworm (Spodoptera Frugiperda) and Physiomorphic Characterization of Maize Varieties Cultivated under Field Conditions in Punjab-Pakistan

Fall Armyworm, Spodoptera frugiperda, the most notorious insectpest of maize, has led to major crop losses globally. The experiment was conducted to study impact of three maize varieties on S. frugiperda populations and their losses assessment. The results revealed that variety YH-1898 had highest germination rate, larval infestation, pupal density, number of tassels, total grain yield, (84.06±2.14%), (15.41±0.61 larvae/plant), (12.44±0.93 tassels/plant) and (9324.71±266.63 kg/acre) standard week-03 to standard week-23, respectively. The variety, FH-2313 was found to be the tallest with plant height, leaf area index, leaf and node count, and internodal distance (67.13±3.71 cm), (70.96±3.97 cm2), (11.44±0.44 leaves/plant), (11.44±0.44 nodes/plant) and (4.33±0.22 cm) respectively. S. frugiperda females deposited 66.13±2.07 eggs/plant with grain yield 6434.06±361.84 kg/acre. Correlation between environmental factors and S. frugiperda population elucidated a positive impact with maximum and minimum temperature (0.766 and 0.679) and negative with relative humidity during morning and evening (0.790 and 0.525).

Progress in developing and deploying drought-tolerant and insect-pest resistant climate-resilient droughtTEGO® and TELA® maize varieties

Currently, drought stress and associated insect-pest damage pose a huge threat to food and nutrition security for over 300 million people in Africa who depend on maize as their main food source. Recurrent drought events cause an annual 17 to 25 percent yield loss of maize in Africa [1]. Compounding the impact of drought, is the ravaging effect of insect-pests infestation on maize production, especially for pests whose population pressure is highly triggered under dry conditions. The crop under weakened conditions created by drought stress and pest effect further becomes constrained biologically and physiologically, thus limiting the crop’s ability to use already limited water and nutrients from the soil. The major insect pests of maize in Africa are fall armyworm (FAW, Spodoptera frugiperda) and various stem borer species (Spotted stem borer (Chilo partellus), African stem borer (Busseola fusca), and the pink stemborer (Sesamia Calamistis). For instance, in Kenya alone, an average of 13 percent or 400,000 tons of maize is lost to stem borer, which is equivalent to the annual maize imports, valued at USD 90 million [2]. The FAW, a transboundary pest, first observed in the continent in 2016, is a maize pandemic that if not controlled adequately, could potentially destroy up to 20 million metric tons of maize annually, enough to feed 100 million people in Africa [3].

A dual-subcellular localized β-glucosidase confers pathogen and insect resistance without a yield penalty in maize.

Maize is one of the most important crops for food, cattle feed and energy production. However, maize is frequently attacked by various pathogens and pests, which pose a significant threat to maize yield and quality. Identification of quantitative trait loci and genes for resistance to pests will provide the basis for resistance breeding in maize. Here, a β-glucosidase ZmBGLU17 was identified as a resistance gene against Pythium aphanidermatum, one of the causal agents of corn stalk rot, by genome-wide association analysis. Genetic analysis showed that both structural variations at the promoter and a single nucleotide polymorphism at the fifth intron distinguish the two ZmBGLU17 alleles. The causative polymorphism near the GT-AG splice site activates cryptic alternative splicing and intron retention of ZmBGLU17 mRNA, leading to the downregulation of functional ZmBGLU17 transcripts. ZmBGLU17 localizes in both the extracellular matrix and vacuole and contribute to the accumulation of two defence metabolites lignin and DIMBOA. Silencing of ZmBGLU17 reduces maize resistance against P.aphanidermatum, while overexpression significantly enhances resistance of maize against both the oomycete pathogen P. aphanidermatum and the Asian corn borer Ostrinia furnacalis. Notably, ZmBGLU17 overexpression lines exhibited normal growth and yield phenotype in the field. Taken together, our findings reveal that the apoplastic and vacuolar localized ZmBGLU17 confers resistance to both pathogens and insect pests in maize without a yield penalty, by fine-tuning the accumulation of lignin and DIMBOA.

Engineered Expression of Vip3A in Green Tissues as a Feasible Approach for the Control of Insect Pests in Maize.

Genetic engineering technology offers opportunities to improve many important agronomic traits in crops, including insect-resistance. However, genetically modified (GM) exogenous proteins in edible tissues of transgenic crops has become an issue of intense public concern. To advance the application of GM techniques in maize, a Cre/loxP-based strategy was developed for manipulating the transgenes in green tissues while locking them in non-green tissues. In the strategy, the site-specific excision can be used to switch on or off the expression of transgenes at specific tissues. In this work, two basic transgenic maize, named KEY, carrying the Cre gene, and LOCK, containing the Vip3A gene with a blocked element, were obtained based on their separate fusion gene cassettes. The expression level and concentration of Vip3A were observed with a high specific accumulation in the green tissues (leaf and stem), and only a small amount was observed in the root and kernel tissues in the KEY × LOCK hybrids. The insect resistance of transgenic maize against two common lepidopteran pests, Ostrinia furnacalis and Spodoptera frugiperda, was assessed in the laboratory and field. The results indicate that the hybrids possessed high resistance levels against the two pests, with mortality rates above 73.6% and damage scales below 2.4 compared with the control group. Our results suggest that the Cre/loxP-mediated genetic engineering approach has a competitive advantage in GM maize. Overall, the findings from this study are significant for providing a feasible strategy for transgenes avoiding expression in edible parts and exploring novel techniques toward the biosafety of GM plants.

First Report of Nezara viridula (Hemiptera: Pentatomidae) as an Emerging Insect Pest of Maize in India

The green stink bug Nezara viridula (Linnaeus) (Hemiptera: Pentatomidae) is an economic insect pest of many cultivated plants around the world.Recently, high population of green stink bug were observedin maize crop during March–May 2020 in Bihar, a leading state of maize production in India. The population changes, damage symptoms, morpho-variants of N. viridula on maize were studied during 2020 and 2021 and presented in this report. For this study, 1 m2 area were randomly selected at three places in the maize field grown at Dumraon, Bihar to record the population of N. viridula at weekly during crop period in the year 2020 and 2021. Also number of maximum adults per plants and per cobs were recorded. The adults of N. viridula were first recorded in maize field during third week of March 2020 and in the same period of year 2021. The mean maximum adults’ population of N. viridula was 43adults/ m2and 34.33 adults/ m2 observed during April 2020 and 202, respectively onmaize crop. The high population densities of the pest may be due to the migration of bugs from other field crops and native vegetation to the cultivated maize crop. During the course of the investigation, maximum 18 adult bugs per plant and 13 adult bugs per corn were recorded during fourth week of April 2020, whereas, maximum 12 adults per plant and 8 adults per cob were recorded during April 2021.The bugs were damage standing maize plants and corn by sucking saps and hindering the growth of plants, cobs as well as the developing kernels. Considering the high population densities, regular appearance of the pest and damage caused to maize crop in the state created an alarming situation for thepest management researchers of the country to develop suitable integrated pest management strategies for the management of N. viridula on maize in the near future.

Diversity of Storage Insect Pests of Maize (Zea mays L.), their Damage and Losses Causes to Maize in Gabilay District, Somaliland

Maize is one of the foremost cereals cultivated today, and it is a queen of cereals. Maize is threatened by a wide range of post-harvest insect pests. Therefore, a survey was conducted in Gabilay District, Somaliland in 2021 to determine the status of storage pests. During the survey a total of 60 maize storage structures were assessed in three villages of Gabilay District namely; Galloley, Ijaara, and Boqor. Data on storage structures, infestation status, grain damage, and weight loss were collected and analyzed by SPPS version 20 and interpreted using descriptive statistics. The result showed that a locally constructed bit was the major storage structure followed by sacks while iron tank is used at the lowest level. Results found also indicated that all storage structures were infested by two major insect pests, i.e., Maize weevil (S. zeamais) and Angoumois grain moth (S. cerealella) at the highest level and by molds and rats to a lesser extent. Galloley site was infested only by maize weevil, while Boqor and Ijaara sites were infested by both maize weevil and angoumois grain moth. Maize weevil accounted for the lion's share of the infestation compared to angoumois grain moth. The highest grain damage was recorded at the bottom position of the storage structure from the Ijaara area followed by Galloley and Boqor. Likewise, grain weight loss was also highest at the bottom position that showed 12.0%. These findings provide benchmark information for developing sustainable management methods for the storage of insect pests of maize in the study area. It is also recommended training on storage methods, management of storage pests and healthy maize preparation should be practiced.

Spesies Serangga Hama Padi dan Jagung serta Intensitas Serangannya di Kabupaten Lahat

Insect pest attack on rice (Oryza sativa L.) and maize (Zea mays L.) could be potential in decrease production. This study aims to determine the insect pest species of rice and maize and attack intensity in Lahat District. This study was conducted using survey methods. The systematic random sampling methodology was adopted for sample population identification. Surveys were conducted in 3 subdistricts (Jarai, Pajar Bulan and Sukamerindu). Found three rice insect pests species. The third species was rice stem borer (Scirpophaga incertulas), leaf folder (Cnaphalocrosis medinalis) and rice bug (Leptocorisa sp). Found one maize insect pest species was fall armyworm (Spodoptera frugiperda). S. incertulas has attacked in 7 locations with low-intensity, Leptocorisa sp has attacked in 2 locations with low-intensity, C. medinalis has attacked in 1 location with low-intensity and S. frugiperda has attacked in 4 locations with low-intensity. Rice stem borer and fall armyworm can attack crop from the vegetative to generative phase.

Electrophysiological and Behavioral Responses of Spotted Stem Borer, Chilo partellus, to Sex Pheromone Components and Their Blends

The spotted stem borer, Chilo partellus (Lepidoptera: Crambidae) is the major insect pest of maize and sorghum crops during the rainy season. The pheromone released by adult virgin females has been reported to consist of (Z)-11-hexadecenal (Z11-16:Ald) as major component and (Z)-11-hexadecenol (Z11-16OH) as minor component. The latter has been reported to reduce the efficiency of major component to trap the male moths. We studied the electrophysiological and behavioral response of male C. partellus moths to Z11-16:Ald, Z11-16OH, their E-isomers (E)-11-hexadecenal and (E)-11-hexadecen-1-ol, and blends. Electroantennogram (EAG) studies revealed that male C. partellus antennae elicited significantly greater responses to both (Z)-11-hexadecenal and (Z)-11-hexadecenol compared to their respective E-isomers. Behavioral response studies through wind tunnel and cage bioassay showed that blends of Z11-16:Ald and Z11-16OH in the proportion of 100:100 and 100:95 elicited significantly higher responses from male moths. The attractiveness of these pheromone components and blends in field also revealed that traps baited with 100:100 proportion was most effective. Our studies clearly showed that the minor alcohol component Z11-16OH is important for enhancing attractiveness of the pheromone and provides a more effective blend for monitoring of this pest.

Co-Transcriptomic Analysis of the Maize-Western Corn Rootworm Interaction.

The Western corn rootworm (WCR; Diabrotica virgifera virgifera) is an economically important belowground pest of maize. Belowground feeding by WCR is damaging because it weakens the roots system, diminishes nutrient uptake, and creates entry points for fungal and bacterial pathogens and increases lodging, all of which can significantly suppress maize yields. Previously, it was demonstrated that belowground herbivory can trigger plant defense responses in the roots and the shoots, thereby impacting intraplant communication. Although several aspects of maize-WCR interactions have been reported, co-transcriptomic remodeling in the plant and insect are yet to be explored. We used a maize genotype, Mp708, that is resistant to a large guild of herbivore pests to study the underlying plant defense signaling network between below and aboveground tissues. We also evaluated WCR compensatory transcriptome responses. Using RNA-seq, we profiled the transcriptome of roots and leaves that interacted with WCR infestation up to 5 days post infestation (dpi). Our results suggest that Mp708 shoots and roots had elevated constitutive and WCR-feeding induced expression of genes related to jasmonic acid and ethylene pathways, respectively, before and after WCR feeding for 1 and 5 days. Similarly, extended feeding by WCR for 5 days in Mp708 roots suppressed many genes involved in the benzoxazinoid pathway, which is a major group of indole-derived secondary metabolites that provides resistance to several insect pests in maize. Furthermore, extended feeding by WCR on Mp708 roots revealed several genes that were downregulated in WCR, which include genes related to proteolysis, neuropeptide signaling pathway, defense response, drug catabolic process, and hormone metabolic process. These findings indicate a dynamic transcriptomic dialog between WCR and WCR-infested maize plants.

Cellular immune responses of the yellow peach moth, Conogethes punctiferalis (Lepidoptera: Crambidae), to the entomopathogenic fungus, Beauveria bassiana (Hypocreales: Cordycipitaceae)

The yellow peach moth (YPM), Conogethes punctiferalis, is a destructive insect pest of maize in eastern China and adapts to diverse environments, especially against pathogens. In insects, innate immunity comprising both humoral and cellular defense responses, is the primary defense against invading microbial pathogens. In this study, we identified five types of circulating hemocytes from the hemolymph of YPM larvae and analyzed their alterations and functions in immune responses to the infection of Beauveria bassiana, an entomopathogenic fungus infesting many lepidopteran species. The identified hemocytes included prohemocytes, plasmatocytes, granulocytes, spherulocytes and oenocytoids. Significant decreases of total and differential hemocyte counts were recorded over time in larvae, after they were injected with B. bassiana conidia. Additionally, hemocyte-mediated phagocytosis and nodulation were initiated in the hemolymph of larvae from the B. bassiana conidia challenge. The introduction of DEAE-Sepharose Fast Flow beads stained with Congo red also induced a strong encapsulation response in the larval hemolymph. Our observations unravel the occurrence of phagocytosis, nodulation and encapsulation in the hemocoel of YPM larvae to fight against the fungal infection, and offer the first insight into the YPM immune system.

​​Identification of Insect Pests of Maize (Zea mays L.) in Girar Jarso and Hidebu Abote Districts, North Shewa Zone, Oromia, Central Ethiopia

Background: Maize is the most important staple food crops in sub-Saharan Africa, including Ethiopia, predominantly produced and consumed directly by the smallholder farmers. Insect pests are the serious pests causing yield loss of maize in field at different growth stages. Methods: The field survey was carried out during 2019-2020 crop growing season. Purposive sampling technique was used for selecting the districts based on the potential producers of maize and a random sampling technique was used to select the kebeles and the stakeholders. Result: The major identified insect pests of maize in the two districts were grass hopper (Hieroglyphus nigrorepletus), maize leaf hopper (Cicadulin ambila), maize pod borers (Helicoverpa armigera, Etiella), maize stem borers (Chilopartellus Swinhoe), Hairy caterpillar (Amsacta albistriga Walker), Black cut worm (Agrotis ipsilon Hufnagal), Maize leaf Aphid (Rhopalosiphum maidis Fitch), Army worm (Mythimna separata Walker), Fall armyworm (Spodoptera frugiperda), Pink stem borer (Sesamiain ferens Walker), Corn Earworm (Helicoverpa zea Boddias), Chafer beetle (Chiloloba acuta Wiedmann), Shoot bug (Peregrinus maidis Ashamed), White grub (Holotrichia consanguinea) and shoot fly (Atherigona soccata).