Insect Diseases Research Articles

Characterization of a cotton interspecific hybrid of American cotton with wild species G. armourianum

Wild species constitute a source of valuable genes for many adverse climatic conditions, disease and pests. To match up the level of quick depleting insect pest and disease resistance and fast evolving pests, it is the urge of the hour to broaden the resistance base. In order to achieve this goal in cotton, wide hybridization was performed between G. hirsutum (AADD) cv. MCU5, CO14 and CO17, and G. armourianum and interspecific hybrids developed were characterized for several morphological characters for obtaining an idea about the status of the various traits. Interspecific hybrid developed with all three G. hirsutum varieties are potential lines for future introgression programs of insect and disease resistance along with other useful traits. The F1 hybrid displayed intermediate expression for most of the traits. Traits like colour of the stem, leaf colour, position of stigma, nectarines of hybrid completely resembled wild parent-and are considered as dominant in expression. The petal spot was present in the hybrid similar to that wild parent, unlike the cultivated parent; this appeared with different levels of intensity in F1 along with other characters like colour of the anther, and filament colour. Hybrids had profuse flowering throughout the year with low pollen load and pollen of variable shape and size expressing sterility to partial fertility. Noteworthy differentiation was seen between the leaf size and size of other plant parts of the hybrid.

The relationship between vector insect populations, natural enemies, and disease incidence of tungro virus during wet and dry seasons

Abstract. Hutasoit RT, Jihad M, Listihani L, Selangga DGW. 2023. The relationship between vector insect populations, natural enemies, and disease incidence of tungro virus during wet and dry seasons. Biodiversitas 24: 4001-4007. Tungro virus is one of the most prevalent viruses affecting rice plants. The tungro virus is frequently found in rice plantations because its green planthopper vector is always present. This study aimed to determine the relationship between the population density of green planthoppers and its natural enemies with the incidence of tungro disease during the rainy and dry seasons in Lanrang, Sidenreng Rappang, South Sulawesi. The research method employed was field monitoring of the population density of green planthoppers, natural enemies, and the incidence of tungro disease. The presence of the tungro virus was confirmed by the molecular method using RTSV and RTBV-specific primers. The results showed three types of tungro vector insects: Nephotettix virescens, Nephotettix nigropictus, and Recilia dorsalis. Nephotettix virescens was the dominant vector insect, with the highest population in March and August of 101 and 51 individuals, respectively. During the dry season, the high population of the three vector insects in August was followed by a high incidence of tungro disease in September, reaching 29.38%. Symptoms of yellow leaves have been confirmed by molecular methods, which indicated that the infection was caused by RTSV and RTBV, as evidenced by the amplification of DNA bands measuring 787 bp and 1400 bp. Data on the population of vector insects and the incidence of tungro disease indicated the importance of determining the ideal time to plant to avoid the plant's susceptible phase during the peak vector population between March and August. The dominant natural enemies found during the observations included Araneus inustus, Tetragnatha maxillosa, Agriocnemis pygmaea, and Menochilus sexmaculatus. Increasing the population of natural enemies could suppress the population of vector insects.

Exposure to ultraviolet-B radiation increases the susceptibility of mosquitoes to infection with dengue virus.

By 2100, greenhouse gases are predicted to reduce ozone and cloud cover over the tropics causing increased exposure of organisms to harmful ultraviolet-B radiation (UVBR). UVBR damages DNA and is an important modulator of immune function and disease susceptibility in humans and other vertebrates. The effect of UVBR on invertebrate immune function is largely unknown, but UVBR together with ultraviolet-A radiation impairs an insect immune response that utilizes melanin, a pigment that also protects against UVBR-induced DNA damage. If UVBR weakens insect immunity, then it may make insect disease vectors more susceptible to infection with pathogens of socioeconomic and public health importance. In the tropics, where UVBR is predicted to increase, the mosquito-borne dengue virus (DENV), is prevalent and a growing threat to humans. We therefore examined the effect of UVBR on the mosquito Aedes aegypti, the primary vector for DENV, to better understand the potential implications of increased tropical UVBR for mosquito-borne disease risk. We found that exposure to a UVBR dose that caused significant larval mortality approximately doubled the probability that surviving females would become infected with DENV, despite this UVBR dose having no effect on the expression of an effector gene involved in antiviral immunity. We also found that females exposed to a lower UVBR dose were more likely to have low fecundity even though this UVBR dose had no effect on larval size or activity, pupal cuticular melanin content, or adult mass, metabolic rate, or flight capacity. We conclude that future increases in tropical UVBR associated with anthropogenic global change may have the benefit of reducing mosquito-borne disease risk for humans by reducing mosquito fitness, but this benefit may be eroded if it also makes mosquitoes more likely to be infected with deadly pathogens.

Minor root and tuber crops in Africa: Cocoyams (Colocasia esculenta and Xanthosoma sagittifolium)

Cocoyams [taro: Colocasia esculentum (L.) Schott and tannia: Xanthosoma sagittifolium (L.) Schott] are staple tuber crops in many countries in Africa, Asia and the Pacific. This review aims to present the value of cocoyam as a minor tuber crop and the extent and challenges of its production in Africa. Cocoyams are primarily grown for their edible corms or cormels, although other parts, such as stalks, leaves and inflorescence, are used for human consumption. Cocoyams are categorized as neglected food crops mainly grown for subsistence use. Taro is more widely grown than tannia globally. Taro is cultivated all over Africa, although West and Central Africa are the main producing regions. Tannia is mainly grown in West Africa where it is still less common than taro. Production of tannia is generally minimal and rarely appears in cocoyam output statistics for the continent. Africa is the main producer of cocoyam, accounting for over 70% of the global output; the bulk of production occurs in the West and Central African region. Despite the high production, food value and economic opportunities, African cocoyam is rarely sold in the international markets. The crop is cultivated to meet food security at small-scale and family farms. It is mostly consumed and marketed locally in fresh state. Cocoyams are commonly produced by resource-limited smallholder farmers who are mostly women. The crop is cultivated on marginal lands where primitive technologies with little inputs are employed. The crop receives little attention from mainstream research organizations in Africa. Other constraints limiting cocoyam production in Africa include a shortage of planting materials, lack of improved high-yielding cultivars, and paucity of information on the proper agronomic practices, and insect pests and diseases, among others. Industrial use and new product developments of cocoyam in Africa should be explored to enhance the crop's economic value, and by extension attract research attention

Potency of Secondary Metabolites from Salacca zalacca, Sonchus arvensis, and Carica papaya against Aedes aegypti L.

Dengue infection is still as a major public health in the world including Indonesia, wherein from January to June showed about 45,387 cases and 432 deaths. There are many prevention and control activities that have been carried out but have not given contented results despite using insecticides. Plants secondary metabolites are confirmed have biological activity and can protecting the plants from an insect pest and diseases. This study proposed that secondary metabolites in several plants have the potential as biolarvicide. This study aimed to determine the potency of secondary metabolites in Salacca zalacca, Sonchus arvensis, and Carica papaya as biolarvicide. Each extract was test in five concentrations of treatment and two controls, negative control using aquadest and positive control using temephos 1%. The third instar larvae of Ae. aegypti mosquito were used in biolarvicide test, with 10 larvae for each treatment and 3 replications for 24 hours. This study revealed that C. papaya extract showed the highest potency as biolarvicide compared to S. zalacca and S. arvensis. The LC50 and LC90 for 24 hours of C. papaya extract were 2.62% and 5.49% respectively.

Ways for the Prosperity of Farmers in Western Hills and Terai, Nepal

The Institute of Agriculture and Animal Science (IAAS) under Tribhuvan University (TU) has launched the internship programme me for their final semester students studying under-graduate level since 2014/15 in its all constituent and affiliated campuses. About 106 UPA mini-theses accomplished by 221 B.Sc. Ag. graduates from the Prithu Technical College (PTC) libraries were systematically arranged and categorized in chronological order based on the disciplinary subjects and thematic areas, and the technologies have been recommended to scale-out for the prosperity of the farmers in the western Tertian mid-hill agro-ecology of Lumbini and adjoining provinces in Nepal. The review revealed that the researches at PTC were concentrated majorly on major food grain crops with five major themes viz. varietal evaluation, crop management, soil nutrient, weed and insect pest management. The review further revealed that the adequate number of researches were in the vegetable crops specially in production packages and value-chain analysis followed by the control of insect pests and diseases both in on-farm and storage structures, suggesting to follow the integrated pest management (IPM) approach. Varietal testing in major field and vegetable crops, and economic survey of chamomile, marigold, honeybees, broiler chicken, cardamom and ginger and oyster mushroom cultivation practices are the newly defined arena to be adopted for harnessing the prosperity of the farmers of the western hills and Terai region in Nepal and its adjoining congenial agro-climatic environment. Future collaboration with the various agriculture related national and international organizations as adopted by PTC on these recent years has to be continued and strengthened further to extrapolate the UPA research innovations obtained from the graduate student’s mini-thesis works.

Frequency of occurrence and identification of nematodes among entomopathogenic organisms in agrocoenoses of Ukraine

The research objects were entomopathogenic organisms (Nematoda, Fungi, Bacteria, and Insecta) collected in agrocoenoses in different regions of Ukraine during 2016–2018 and 2020–2021. The following research materials were used: soil samples, soil live-traps, specimens of Galleria mellonella L., 1758 (Lepidoptera: Pyralidae) and potential host insects (Coleoptera: Elateridae, Tenebrionidae, Melolonthinae; Lepidoptera: Noctuidae). We analysed 312 samples (220 soil + 92 live-trap samples) and >100 specimens of potential host insects. Our data demonstrate that in soils of agrocoenoses, favourable conditions are created for the dispersal of entomopathogenic organisms. We report the frequency of occurrence of insect-pathogenic nematodes in agrocoenoses of Ukraine, and describe their identification and the specifics of pathology they cause to the insect Galleria mellonella in the context of other entomopathogenic organisms. The frequency of occurrence (% of samples) of entomopathogenic nematodes (genus Steinernema Travassos, 1927 and genus Heterorhabditis Poinar, 1976) in agrocoenoses was the highest among other organisms that caused infectious and parasitic diseases of insects and were found in 15% of the samples. Three species of entomopathogenic nematodes—Steinernema carpocapsae (Weiser, 1955) Wouts et al., 1982, Steinernema ex gr. ‘glaseri‘, and Heterorhabditis bacteriophora Poinar, 1976—have been identified. We have found 8% of samples to contain fungal disease-causing agents (genera Beauveria Vuill., 1912, Metarhizium Sorokin, 1879, and Akanthomyces Lebert, 1858). The frequency of occurrence (%) of all remaining causative agents of infectious and parasitic diseases of insects, namely bacterial diseases and myiasis (infection of a fly larva) (Diptera: Tachinidae) were 3% and 2%, respectively. A mixed infection was detected in 2.5% of the total number of analysed samples; nematodoses-mycoses mixed infections were most often recorded. We have recorded the phenomenon of hyperparasitism with nematodosis-entomosis co-infection inside dead G. mellonella larvae for the first time.

Evaluation of cytogenetic effect of pesticides in onion root meristem

Farmers use chemical insecticides, fungicides and herbicides to control insect pests, diseases and weeds. Extensive use of chemical pesticides is becoming hazardous to the environment and human and animal health. Biopesticides have been used as a safer alternative. Cytogenetic analysis is needed to determine the effects of chemical and biopesticides in plants if these are used frequently in an improper concentration. This investigation assessed the effects of a chemical systemic insecticide ‘Actara 25WG’ and a bioinsecticide ‘Bio Sona’ for seed germination and on root mitosis of five onion varieties. Three concentrations of Actara 25WG were used as seed treatment, viz., 25 g, 50g (recommended) and 75 g/kg seed. Similarly, Bio Sona was applied @ 2 %, 5 % (recommended) and 8 % concentrations. Depressing effects of the two pesticides were recorded in seed germination percentage except for Bio Sona 2% in variety Bhima Shakti. Actara 25WG and Bio Sona showed either mitoenhancing or cytotoxic effects depending on dose and variety. These pesticides also induced genotoxicity at recommended and higher doses on root tip cells as indicated by the frequency of total chromosomal aberrations like binucleate cells, clumps, stickiness, disturbed stage, laggards, bridges and fragments. Bio Sona at higher concentrations showed more aberrations than Actara 25WG. There were differential responses of the varieties to the pesticide treatment. More research must be done on the effects of chemicals and biopesticides in plants to assess their cytogenotoxicity.

FH-444: A HIGH YIELDING AND SUPERIOR FIBER QUALITY UPLAND COTTON VARIETY SUITABLE FOR COTTON GROWING AREAS OF PUNJAB, PAKISTAN

FH-444 is a new Bt cotton variety which was released during the year 2020-21 by Cotton Research Station, Ayub Agricultural Research Institute, for irrigated areas of Punjab, Pakistan to maintain fiber quality and production through gradually replacement of existing cotton cultivars to avoid the yield losses caused by insect, pest and unexpected disease attacks. The FH-444 possesses drought tolerance and very good combination of traits to meet the requirements of the farmers, pickers, ginners, spinners and textile industry. The evaluation of this promising line was started during 2011-12 in different yield tests viz: preliminary & advance yield trials, Provincial Coordinated Cotton Trial (PCCT), National Coordinated Varietal Trial (NCVT), Distinctness, Uniformity and Stability (DUS) Trial, Agronomic trials, 1.25 Acre trials etc. In preliminary yield trials, FH-444 showed 45.96% increase in yield (3592 kg/ha) over standard variety FH-113 (2461 kg/ha) during 2011-12 while in advanced yield trials, FH-444 exhibited 23.61% increase in yield (3408 kg/ha) over standard variety FH-113 (2757 kg/ha) during 2013-14. It was also found that the effects of Cotton Leaf Curl Disease (CLCuD) were low (1.7 %) in FH-444 during growing season of 2014-15, while FH-142 showed increased incidence of attack (4.9%). FH444 demonstrated significant resistance with respect to thrips, whitefly, jassid and pink bollworm infestation. In present study it was found that the variety FH-444 possesses higher yield potential and will contribute to improve cotton yield and production under different stress conditions.

I. L. Serbinov: milifaceted personality of a scientist

The article is dedicated to the 150th anniversary of the outstanding Ukrainian scientist Ivan Lvovich Serbinov (1872–1925). The life and activity of the researcher took place during a rather difficult time. It includes several revolutions, the First World and civil wars, fundamental changes in social and political spheres. But despite all the difficulties, this period was also marked by significant scientific achievements, emerging a large number of outstanding scientists, in particular, in the field of biology. Having studied the scientific heritage of the investigator, it is possible to prove the exceptional versatility of his activity. I. L. Serbinov worked in the field of mycology, microbiology, phytopathology, studied insect and fish diseases. He wrote more than 100 works and twice as many essays and abstracts dedicated to phytopathology. However, the biggest breakthrough in science is his research on bacterial plant diseases. Serbinov developed a method of studying plant bacteriosis; described and studied causative agents of diseases on potatoes, beets and other garden plants, fruit trees and grapes; discovered new species of bacteria parasitic on plants. Formulated by Serbinov’s doctrine on mixed infection is a valuable contribution to the theoretical and practical achievements in microbiology. In addition to the research field, the authors emphasize the lecturing and popularizing activities of the scientist. The main directions of research in various periods of Serbinov’s life such as St. Petersburg, Crimea and Odesa are also analyzed. It is noted that the scientist’s priority in many fields of biological science was recognized not only by his contemporaries – A. A. Yachevsky, M. S. Voronin, A. S. Bondartsev, but also the following generations of researchers, among which were M. V. Horlenko, K. H. Beltyukova, R. I. Hvozdyak etc.

Effects of Climate Change on Poultry Production in Ebonyi State, Nigeria

Three agricultural zones of Ebonyi State, Nigeria, were considered for this study. Using Pearson Product Moment Correlation (PPMC) to establish the relationship between the variables and how one independent variable influences the dependent variables. The study aimed at examining the effects of climate change on poultry production. The study's primary objectives were to assess the socioeconomic characteristics of poultry farmers, ascertain the extent of climate awareness, determine the effect of climate change on poultry production, determine climate change adaptation strategies for coping with it, and identify the constraints encountered in poultry production. Four local government areas in the state of Ebonyi were the locations of data collection from September to October 2021. A multistage sampling procedure was used for the collection of respondents. The study found that 56.9% of the respondents were female, 42.2% were in their active age 30 to 40, 54.9% had a Bachelor’s degree, 64.7% had spent more than years of farming experience, and 29.4% were managers of their poultry production. Farm size had little effect on poultry production; climate change had an effect on feed consumption and has caused the spread of pests and diseases and the death of young ones. According to the study's findings, the respondents were in agreement that changing to intensive livestock management and collecting runoff water in ditches during periods of drought constituted adaptation to climate change. It was determined that climate change had an enormous and negative effect on poultry production through insect infestation and disease outbreak. Therefore, relevant Nigerian government agencies should offer financial assistance to poultry farmers along with adaptation training.

Diseases of black soldier flies Hermetia illucens L. a future challenge for production?

Pathogens are a challenge for all biological production systems. For producers of insects for food and feed, they can result in extensive production and economic losses. Black soldier flies (BSF) are considered very robust and resistant to insect diseases, however, emerging diseases may suddenly appear in the future. Insects can become infected by many types of pathogens such as bacteria, fungi, nematodes and viruses. BSF have been experimentally infected by fungal, bacterial and nematode entomopathogens in the laboratory and recent bioinformatics studies have revealed evidence of the presence of past and present viruses in BSF samples. Mitigation of emerging BSF pathogens, will require further research and development that include collaboration between scientists, laboratories specialised in insect pathology as well as with the industry.

A meta-analysis on rootstock-induced effects in grafted watermelon (Citrullus lanatus var. lanatus)

Sweet watermelon (Citrullus lanatus var. lanatus) grafting with complementary rootstocks is necessary for new variety design and to enhance product profiles, including fruit yield and quality and tolerance to biotic and abiotic stresses.. Integrated selection of successful watermelon grafts using multiple traits ensures breeding and economic gains. Therefore, the objective of this study was to undertake a meta-analysis on the responses of watermelon when grafted with contrasting rootstocks involving cucurbit species or interspecific hybrids using agronomic, physiological and quality traits, and insect pest and disease reactions for rootstock selection, variety development and deployment. A meta-analysis was conducted involving 65 studies, and data were analysed using various statistical methods. Results indicated significant (p < 0.05) variations among watermelon varieties for economic traits when grafted onto different cucurbit rootstock species. Interspecific hybrid [Cucurbita maxima × C. moschata] and Lagenaria siceraria (Molina) Standl rootstocks induced high and variable effects on fruit yield and related traits of grafted watermelon.. Watermelon/L. siceraria graft combinations showed high phenotypic variation on sugar profiles. Lycopene content of grafted watermelon was highly variable when grafted onto C. lanatus var. citroides and C. maxima × C. moschata rootstocks. Graft combinations involving L. siceraria and C. maxima × C. moschata were significantly (p < 0.05) differentiated for fruit flesh firmness and color. C. lanatus var. citroides rootstock enhanced low and variable infections for root-knot nematodes, whereas C. maxima × C. moschata rootstock induced high and variable resistance to Fusarium and Verticillium wilt in grafted watermelon. Fruit yield and quality traits of grafted watermelon positively and significantly (p <0.05; p <0.001) correlated with root and photosynthetic parameters useful in selection programs. Overall, the meta-analysis revealed the need to integrate root traits (e.g., increased root weight and total root length, higher root surface area and average root diameter), high photosynthetic efficiency, fruit yield and quality in selecting desirable rootstock in the development of market preferred watermelon varieties.

Chemo-prospecting Cleistanthus collinus, Lantana camara and Strychnos nux-vomica for rice pest management under laboratory conditions

Cleistanthus collinus Roxb., Lantana camara L. and Strychnos nux-vomica L. are abundantly available in tropical countries and are being used for pest management as an Indigenous Technical Knowledge. The present study decoded the biochemical constituents of these species and tested the efficacy of these plant products against major rice insect pests and diseases. Significantly higher phenol content and antioxidant activity (2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2-Azinobis (3-ethyl-benzothiazoline-6-sulfonic acid (ABTS) assay) were found in C. collinus water extract, whereas S. nux-vomica extract had higher flavonoids. The major chemical constituents of C. collinus, L. camara and S. nux-vomica were 1,2,3-Benzenetriol, β- Phellandrene and Phytol, respectively. Water extract of C. collinus had significantly reduced the insect pests (brown planthopper, Nilaparvata lugens Stål and gall midge, Orseolia oryzae Wood-Mason) and diseases (brown spot, Helminthosporium oryzae and bacterial leaf blight, Xanthomonas oryzae pv. oryzae). In contrast, S. nux-vomica water extract was most effective against the pathogens causing blast, Magnaporthe oryzae and sheath blight disease, Rhizoctonia solani in rice. The secondary metabolites, namely, 1,2,3-Benzenetriol, Neophytadiene, n-Hexadecanoic acid, Phytol etc. present in C. collinus extract reported to have biocidal activities against number of crop pests. As C. collinus has been listed as ‘vulnerable’ in the International Union for Conservation of Nature (IUCN) red list, it can be promoted as a viable component in Integrated Pest Management (IPM) of rice for its conservation and economic utilization.

Hybrid insect protection and fungicide application for managing ear rots and mycotoxins in silage corn

AbstractMycotoxins in silage corn (Zea mays L.) accumulate due to ear rot infections by certain ascomycete fungi and cause health issues in livestock. Fungal infections intensify with increase in ear‐damaging insect injury and favorable environment in the US Great Lakes region. Therefore, evaluating strategies such as hybrid insect protection and fungicide decisions to manage insects, ear rots, mycotoxin, and silage quality is crucial. Field trials were conducted in randomized complete block design at 11 Michigan site‐years across 2019–2021 using three hybrid insect protection levels under two levels of prothioconazole fungicide (treated and non‐treated). Hybrids (two per level) included: conventional (non‐Bt); Bt with Cry1F and Cry1Ab (BtE), protection only against European corn borer (ECB); and Bt with Cry1F and Vip3A (BtEW), protection against both ECB and western bean cutworm (WBC). Insect injury and ear rot index were 80%–90% and 75%–90% lower, respectively, in BtEW hybrids than non‐Bt hybrids. Strong correlation between insect injury and ear rot severity was observed when insect pressure was high. Mycotoxin levels, particularly deoxynivalenol (DON), was also lowest in BtEW hybrids. Weak correlations were observed between ear injury and mycotoxin concentration. Under low disease pressure, a 50%–70% reduction was observed in fungicide treated plots for both ear rot incidence and DON concentration. However, fungicide application did not reduce ear rot infections driven by high insect injury. Treatments had negligible impact on forage quality. Overall, results indicated that incorporating insect protection in hybrid selection decisions reduced insect feeding, disease occurrence, and mycotoxins, especially under high insect pressure.

Colonization and endophytic effect of Beauveria bassiana (Bals.-Criv.) Vuill. UHSB-END1 against Myzus persicae (Sulzer) and Plutella xylostella (L.) in cabbage

BackgroundFungal microbial biocontrol agent playing an important role in sustainable pest management with low cost. Conidial contact with cuticle is sufficient to cause disease in insects by entomopathogenic fungi (EPF) compared to bacteria and viruses which required ingestion of contaminated food. The field level application of fungi resulted inconsistent in their efficacy against insects as they withstand in the agroecosystem with adverse environmental conditions. To overcome this bottleneck, endophytic EPF, Beauveria bassiana (Bals.-Criv.) Vuill. (Cordycipitaceae: Hypocreales), is well-studied for the management of insects of cultivated crops and got promising results. The colonization of endophytic isolates varied from one host plant to another and virulence against insects too. Hence, the study was undertaken to know the colonization of indigenous B. bassiana UHSB-END1 isolate in cabbage plant and its efficacy against major insects of cabbage.ResultsThe indigenous isolate of B. bassiana UHSB-END1 was able to colonize cabbage in all the methods of inoculations (seed treatment, seedling root dip, soil drenching, foliar spray and combination treatment) at 30, 45 and 60 days of post-inoculation (dpi). However, the colonization of the fungus inside the cabbage was restricted to tissues of inoculation, and movement from the site of inoculation to other parts of the plant was poor. In the present study, colonization was the highest at 30 dpi in all methods of colonization with restricted colonization to the site of exposure of fungus. Further, in vivo and in planta assay confirmed the effectiveness of B. bassiana UHSB-END1 colonized cabbage against Myzus persicae (Sulzer) and Plutella xylostella (Linnaeus). Under in vivo conditions the maximum mortality of M. persicae and P. xylostella was recorded at 30 dpi. It was decreased slightly at 45 dpi, and the lowest morality was recorded at 60 dpi. In planta experiment also proved better efficacy against both the test insects. Wherein mortality of M. persicae ranged from 22 to 36% five days after release (DAR), it was increased to 48–68% at 10 DAR and reached highest mortality rate at 15DAR (72–96%). Similarly, mortality of P. xylostella ranged from 14 to 24% after five DAR, and it was 27–44% at 10 DAR, and maximum mortality rate of larvae were recorded at 15 DAR (64–96%).ConclusionThe present study reported 100% colonization of cabbage plant by indigenous B. bassiana UHSB-END1 at 30 dpi in combination of treatment and showed a maximum efficacy in managing the population of major insects of cabbage. Introducing this indigenous isolate will pave a ray of hope in managing the both key insects (P. xylostella and M. persicae) in cabbage agroecosystem without disturbing the environment and further helps in production of cabbage with minimum pesticide residue for consumers.

Sex-typing of ingested human blood meal in Anopheles stephensi mosquito based on the amelogenin gene.

Identifying the sex of human hosts of insect disease vectors, using PCR amplification of the amelogenin gene (AMEL) from the ingested blood meal is an increasingly useful technique for epidemiological studies of vector-borne diseases, as well as within the criminal justice system. Detection of DNA from ingested blood is influenced by the choice of DNA extraction method, genomic target region, type and length of PCR, and rate of degradation in the DNA samples over time. Here, we have tested two types of PCR (i.e. conventional and nested), producing differently-sized PCR products, in time-course assays targeting the human AMEL gene in Anopheles stephensi mosquitoes that were fed on human male and female blood. The fed female mosquitoes were allowed to digest at 28°C for times ranging from 0 to 120h. Three AMEL primer pairs were used to amplify three sequences that were 977, 539, and 106 bp for the X chromosome and 790, 355, and 112 bp for Y. We found that time since feeding had a significant negative effect on the success of PCR amplification. The shortest fragments (106 and 112 bp) were amplified for the longest time after blood feeding (up to 60h), whereas the medium and longest loci were not amplified by conventional PCR even at 0h. However, the nested PCR protocol, targeting the medium sequence, could detect small amounts of human DNA up to 36h (1.5 days) after the blood meal. The shortest PCR assay standardized herein successfully detected small amounts of human DNA in female mosquitoes up to 60h after the blood meal. This assay represents a promising tool for identifying the sex of the human host from the blood meal in field-collected female mosquitoes.

Characterization of fruit production and market performance in northwest Ethiopia

BackgroundIn Ethiopia, fruits pose a significant production and marketing challenge for farm households that significantly affect their farm profitability due to their perishability and unpredictable seasonal pricing. For instance, seasonally, market prices vary depending on the quality and quantity of fruit products available on the market. Stemming from this logical ground, this study is initiated with the objective of characterizing production systems and market performance of fruits in Ethiopia, focusing on apple and mango crops.MethodsA random sampling approach was used for producers and snowball sampling for traders when selecting survey participants. A pre-tested survey questionnaire was used for data collection. Descriptive statistics and market margins were used for statistical analysis.ResultsPost-harvest wastage is preventing farmers from receiving anticipated revenue, implying that approximately 31.8 and 26.1% of the total mango and apple produce was lost, respectively. According to the survey results, there was no measurement consistency among farmers, local collectors, and small retailers. District level collectors received a higher margin share (42.66 and 40.18% of apple and mango, respectively) than other actors in the chain, which was unjustified given their contribution to the market chain. Farmers were comparatively hampered by the market since they earned the lowest share (33.34 and 15.08% of apple and mango, respectively) of consumer prices indicating that the apple and mango market chain performance is poor. As a consequence, these all deter farmers from producing in large quantities, quality, and also uncertainty (fair failure in the mind of farmers) in the marketing of apples and mangoes.ConclusionsThe awareness of small-scale farmers about most of the agronomic practices including insect pests and diseases were very low. Hence, this study recommended that there is an urgent need from district agricultural offices to improve mango and apple production and marketing systems in the study districts.

Genomic and cytogenetic analysis of the Ceratitis capitata temperature-sensitive lethal region.

Genetic sexing strains (GSS) are an important tool in support of sterile insect technique (SIT) applications against insect pests and disease vectors. The yet unknown temperature-sensitive lethal (tsl) gene and the recently identified white pupae (wp) gene have been used as selectable markers in the most successful GSS developed so far, the Ceratitis capitata (medfly) VIENNA 8 GSS. The molecular identification of the tsl gene may open the way for its use as a marker for the development of GSS in other insect pests and disease vectors of SIT importance. Prior studies have already shown that the tsl gene is located on the right arm of chromosome 5, between the wp and Zw loci (tsl genomic region). In the present study, we used genomic, transcriptomic, bioinformatic, and cytogenetic approaches to characterize and analyze this genomic region in wild-type and tsl mutant medfly strains. Our results suggested the presence of 561 genes, with 322 of them carrying SNPs and/or insertion-deletion (indel) mutations in the tsl genomic region. Furthermore, comparative transcriptomic analysis indicated the presence of 32 differentially expressed genes, and bioinformatic analysis revealed the presence of 33 orthologs with a described heat-sensitive phenotype of Drosophila melanogaster in this region. These data can be used in functional genetic studies to identify the tsl gene(s) and the causal mutation(s) responsible for the temperature-sensitive lethal phenotype in medfly, and potentially additional genes causing a similar phenotype.

GENETIC DIVERSITY, PRODUCTION, AND TRADE OF CHILI WITH SPECIAL REFERENCE TO NEPAL

Chili is a popular spice crop in Nepal, a country with countless genetic diversity and a wider distribution covering areas from the tropics to the warm temperate regions. However, the exploitation of chili’s genetic potential to improve yield has faced challenges by different factors. An analytical study on genetic diversity, production challenges, and marketing opportunities of chili was still lacking in Nepal. This study aims to provide information on chili diversity, its distribution, and uses in Nepal, discussing the potential role of chili in Nepalese agriculture. Mainly, the study is a desk review complemented with a field study. Total chili production increases with an increasing area under cultivation over the years. In 2021, chili production covered 23,083 ha, 13% higher than in 2020. Per capita chili consumption is estimated at 9.8 kg in 2021. Diversity in chili phenotypes grown in the study area of Nepal has been noted. On a nine-point scale, higher variations showed in fruit traits (5 ± 1.5), floral morphology (4 ± 0.8 distinct types of flowers), leaf size (3 ± 0.7), plant height (3 ± 0.8), and maturity (3 ± 0.8) among chili genotypes in the area studied. Insect pests (15.6%) and diseases (16.4%) emerged as the main problems in chili cultivation, followed by drought stress (14.8%) and a shortage of fertilizers (10.1%). Marketing-related issues shared 2.7% among the 12 main concerns, particularly farmers who suffered more from inadequate market information. In addition, estimates on seed requirements, seed sources, existing chili varieties, and market segments also gained focus. The need for demand-based action research to strengthen Nepalese chili production and marketing proves imperative to fulfill the growing domestic demand and export potential.