Abstract: The life cycle of the invasive alien insect pest, fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), was studied using a colony established from field-collected larvae. Eggs, neonate larvae, and newly emerged adult moths were used in experiments to investigate the basic biology of the FAW. Adult females laid up to 1184 eggs with a mean of 469 ± 22 eggs per female. The incubation period of eggs and percentage hatchability were 2-3 days and 80–87%, respectively. The mean larval lengths from the first to the sixth instar were 4.63, 6.60, 9.76, 15.86, 25.13, and 27.81 mm, respectively. The mean larval weights were 0.003, 0.019, 0.045, 0.050, 0.060, and 0.067 g, respectively, for the six instars. The mean width of the head capsule of the sixth instar larva was 2.76 mm. The total larval duration throughout the six instar stages was 16–18 days, while the mean pupal weight was 0.25 ± 0.001 g and 0.35 ± 0.011 g for males and females, respectively. The mean pupal length was 14.3 ± 0.16 mm for males and 17.2 ± 0.14 mm for females. Pupal duration ranged from 8 to 14 days, with a mean of 10.35 ± 0.26 days, while the pupal emergence rate ranged from 60 to 94%, with a mean of 80.25 ± 1.28%. The life cycle of males lasted 33–44 days and that of females lasted 36–49 days under laboratory conditions. Adult copulation occurred between 8 and 11 pm, with the peak occurring at 9 pm. This study provides baseline information about the biology of the FAW. Apart from being an important reference point for future research on the FAW, the data provided would aid FAW management decision-making. PubDate: Sat, 29 Apr 2023 06:50:01 +000
Abstract: Free-ranging domestic cats (Felidae, Felis catus) can potentially play host to some life-threatening zoonotic pathogens including ectoparasites such as fleas, ticks, and lice. These ectoparasites are capable of transmitting zoonotic disease. Cats (Felis catus) were captured using baited cage traps with raw red meat from five parks in central areas of Tehran, Iran, in the summer of 2018. The collected cats were moved to the laboratory, and their ectoparasites were removed from their skin by forceps and combing for five minutes for each cat. Ectoparasites were stored in 70% ethanol and later mounted for identification of species, using species identification keys. Forty-one cats were collected from these study areas. Among all captured cats, 26 specimens (63.41%) were infected with 83 ectoparasites and the average infection rate was 3.19 in cats. Six arthropod species were identified, including four fleas (89.16%), one louse (8.43%), and one tick (2.41%). The four flea species included Ctenocephalides canis (39.76%), Ctenocephalides felis (18.07%), Xenopsylla nubica (16.87%), and Pulex irritans (14.46%). The one louse species was Trichodectes canis (8.43%), and the one tick species recovered was identified as Hyalomma spp. (2.41%). Based on the findings, Ctenocephalides canis was the most common ectoparasite species (39.76%). Fleas were the most prevalent ectoparasites on Felis catus cats, with the highest prevalence, observed for Ctenocephalides canis. Due to the large and growing population of cats and the high risk of transmission of common diseases between humans and cats, as well as the high contact and communication of people with cats, we were encouraged to study the ectoparasites of cats in five important parks in the city of Tehran. PubDate: Fri, 03 Mar 2023 07:20:00 +000
Abstract: Malaria is a mosquito-borne life-threatening parasitic disease of humans and the leading cause of mortality and morbidity in sub-Saharan Africa. Despite the major efforts made towards malaria control, it is facing challenges of development of parasite resistance towards antimalarial drugs coupled with Anopheles vector resistance towards insecticides being used in control. There is, therefore, a need to develop complementary control strategies that are economical and environmentally friendly. Biological control using entomopathogenic fungi against the immature malaria mosquito vectors presents an untapped opportunity. This study sought to isolate and characterize entomopathogenic oomycetes Lagenidium giganteum and L. ajelloi from wild Anopheles larvae from Ahero rice fields in western Kenya and test their pathogenicity against laboratory-reared Anopheles gambiae larvae. Laboratory-reared A. gambiae larvae (3rd and 4th instar) were exposed to five different concentrations of L. giganteum and L. ajelloi zoospores; 1000, 2000, 3000, 4000, and 5000 zoospores/mL, respectively. The larval mortality was recorded after 24, 48, 72, and 96 hours post-exposure, until all larvae were dead. The results obtained showed that L. giganteum was not pathogenic to A. gambiae larvae after 24 and 48 hours post-exposure to all concentrations. Larval mortality was recorded at 72 and 96 hours. There were no significant differences observed in the mortalities from all treatments. No mortalities were observed in deionized water (negative control) whereas 100% mortality was recorded in larvae exposed to Bti (positive control). Probit analysis showed that LC50 after 72 hours and 96 hours was 2.32 × 104 and 3.51 × 103 zoospores/ml, respectively. L. ajelloi caused larval mortalities at all the 5 test concentrations after 24-, 48-, 72- and 96-hours post-exposure with LC50 values of 1.18 × 105, 1.43 × 104, and 6.05 × 102, and 27.08 zoospores/ml, respectively. This study isolated and tested two species of Lagenidium from field collected larvae. Lagenidium ajelloi recorded greater pathogenicity than that of L. giganteum against A. gambiae larvae, making them potential candidates for use in the development of bio-larvicide for the control of Anopheles larvae. PubDate: Mon, 27 Feb 2023 07:35:01 +000
Abstract: Entomopathogenic fungi (EPF) of different genera are known to have the potential to engage in fungus-plant interactions as fungal endophytes. This hidden endophytic interaction offers several advantages to host plants, such as insect pest management. Hence, this study aimed to explore the endophytic potential and virulence of EPF collections after artificial inoculation. A total of 27 EPF isolates from the genera Beauveria and Metarhizium were screened for virulence. Two inoculation methods (leaf and seed dressing) were used to study the endophytic colonisation potential of the selected isolates. There was a significant variation among the tested isolates in their ability to kill C. partellus larvae. Lower mean percentage mortality was recorded for isolates B4, DS-51-21, and B1,9 which scored 28.01%, 32.29%, and 34.58%, respectively. All the screened EPF isolates were able to colonise maize tissues after artificial inoculation, except for APPRC-34GM. The percent colonisation of maize tissues varied with strains, and delivery methods ranged from a minimum of 0% to a maximum of 53%, where the maximum was recorded by S#10H. Larval mortality after feeding maize leaves inoculated with EPF ranged from 18% to 60%. The findings of this study indicated that Beauveria spp. and Metarhizium spp. have the potential to colonise maize after artificially inoculating and translocating from the site of infection. Hence, the potential to move from the site of infection and larvicidal activity after colonisation may give the advantage to manage insect pests acting on the different parts of maize. PubDate: Wed, 21 Dec 2022 13:50:01 +000
Abstract: From April to July 2019, an experiment was conducted in Khumaltar, Lalitpur (27°39.312′N, 85° 19.586′E, and 1322 m above sea level) to assess the effectiveness of plant materials on maize weevil (Sitophilus zeamais Motsch.) control under laboratory conditions (maintained room temperature of 28.5 ± 2°C, and relative humidity of 72 ± 5%) treatments were Acorus calamus (rhizome powder) @ 5 g·kg−1, Melia azadirach (rhizome powder) seed) @ 5 g·kg−1, Curcuma domestica (rhizome powder) @ 5 g·kg−1, mustard oil @ 2 mL·kg−1, Gingiber officinalis (rhizome powder) @ 5 g·kg−1, rice husk ash @ 5 g·kg−1, and an untreated control. These treatments were evaluated in a completely randomized design (CRD) with three replications. At four months, the grains treated with Acorus calamus had the least weight loss (6.66%), and grain damage (1.23%). Grain damage (18%), and weight loss (62.33%) were the highest in the control treatment. Similarly, grains treated with Acorus calamus had the fewest number of exit holes (3.10 per 100 g of maize seed), while the control treatment had the largest number of exit holes (45.10 per 100 g of maize seed). There was a significantly higher number of weevils in the control treatment (55.80 per 250 g maize grains), but only a few numbers of weevils in the Acorus calamus-treated grains (2.50 per 250 g maize grains). In contrast with other plant materials treated grains, the maize weevil showed a reduced preference for Acorus calamus- treated grains with low weight loss, and grain damage. These findings can be used to promote locally accessible botanicals for maize weevil control in Nepal. PubDate: Wed, 26 Oct 2022 08:05:02 +000
Abstract: The quality of feed plays an important role in the growth and development of silkworms and eventually in the economic traits of cocoons. This study was conducted to evaluate ten castors (Ricinus communis L.) genotypes and their feeding values on the rearing performance of Eri Silkworm (Samia cynthia ricini Boisduval) (Lepidoptera: Saturniidae) at Tepi, southwest Ethiopia. A total of ten castor genotypes were evaluated in a randomized complete block design (RCBD), and the suitability of castor genotypes as feed for a mixed strain of Eri-silkworm was also evaluated in a completely randomized design (CRD) under laboratory conditions. A hundred worms were used in each replication. Castor genotypes showed significant differences in fresh leaf yield. Among the castor genotypes tested, genotype 219645 recorded 439 g of ten fresh leaf yields. Results of Eri-silkworm rearing performance depict that a shorter larval period (22 days), a higher effective rate of rearing (94.54%), and a shorter life cycle (58 days) were observed in Eri-silkworm fed on leaves of the 200390 genotype, while a higher larval weight (6.16 g) was recorded in the Abaro genotype. However, higher cocoon weight (3.26 g), pupal weight (2.46 g), shell weight (0.45 g), and silk ratio (13.80%) were found in Eri-silkworms fed on leaves of genotype 219645. Hence, based on silkworm rearing performance, genotype 219645 showed relatively superior results and is recommended for future development work. Further studies should continue giving more emphasis to the multilocation study of genotype 219645 to understand its performance in the diverse growing environment. PubDate: Mon, 03 Oct 2022 03:05:02 +000
Abstract: The use of larvicides, especially in endemic regions, is recommended for malaria control. However, due to the excessive use of synthetic larvicides, resistance in mosquitoes and environmental pollution have been challenges. In the current study, nanoliposome containing clove and cinnamon essential oils and their major ingredients, i.e., eugenol and cinnamaldehyde, were first prepared; particle size and successful loading were investigated using DLS (Dynamic Light Scattering) and ATR-FTIR (Attenuated Total Reflection-Fourier Transform InfraRed) analysis. Larvicidal effects of the nanoliposomes and nonformulated samples were then investigated against Anopheles stephensi. The best-observed efficacy (LC50 5.4 μg/mL) was related to nanoliposomes containing eugenol with a particle size of 109 ± 4 nm. However, LC50 values of the other three nanoformulations were also around 10 μg/mL; all four prepared nanoformulations were thus introduced as natural larvicides for further investigations in the field conditions. PubDate: Fri, 16 Sep 2022 12:20:01 +000
Abstract: The spatial distribution and seasonal dynamics of the spotted lanternfly (Lycorma delicatula) on tree of heaven (Ailanthus altissima) were studied in Pennsylvania through weekly sampling of 30 trees (6 sites, 5 trees/site) from 27 July to 8 November 2020. Adults found on each tree were separated into six within-tree positions (lower trunk, middle trunk, upper trunk, first branch, second branch, and above second branch) by four directions (East, South, West, and North). In total, 78,796 adults were counted at the six study sites during the 15-week period. Significant differences in total adult count were found among trees, with a mean of 2,627 (254–12,023) adults/tree. Study site, tree diameter, and cardinal direction had no significant impact on adult spatial distribution. However, significantly more adults were found on the middle (1077), the lower (865), and the upper trunk (337) compared with the first (194), the second (93), and above second branches (60). Most adults were congregated on the lower and middle trunks. Seasonal dynamics followed adult development and migration patterns in the field, with peak populations observed in weeks 35 (24–30 August) and 37 (7–13 September) before declining. Female-based sex ratios ranged from 77.3 to 100% according to weekly monitoring of the lower 1 m trunk of 10 trees at 2 sites (5 trees/site) for 12 weeks from 17 August to 8 November, with 7,356 females and 197 males counted, respectively. Impact factors such as attack patterns, intraspecific congregation, adult seasonality, and sexual dimorphism in host selection are discussed. PubDate: Tue, 30 Aug 2022 12:20:02 +000
Abstract: In a symbiosis, each participant gains more fitness benefits than is paid in maintenance costs for the symbiosis. The mugwort aphid, Macrosiphoniella yomogicola, is ant-associated, and the host mugwort Artemisia montana is a genet-producing plant that has clonal aboveground shoots. M. yomogicola infests most A. montana shoots from spring to midsummer, and attending ants also repel leaf-eaters of the host plant. However, most aphid colonies become extinct after budding of A. montana inflorescence after early August. A few surviving aphid colonies (1∼3 per genet) produce sexuparae in mid-October. The shoots on which the sexuparae emerged lost most of their fitness because the aphids strongly suppress budding and growth of inflorescence. However, as the shoots are genetic clones of each other, the appearance of stem mothers in the next spring may result in early spreading of the aphids and attending ants to clonal shoots, which would protect the host from leaf-eaters. Here, we show that all shoots on a genet with stem mothers are occupied by aphids and ants much faster than those on a genet without stem mothers. The attending ants repel leaf-eaters to unimportant leaves for the host. Our results suggest that, as the shoots of a genet are all clones, sustaining the aphids on a few shoots may be beneficial to a genet as a whole through kin selection. PubDate: Tue, 31 May 2022 04:20:03 +000
Abstract: West Nile (WN) virus has been detected in Morocco in 1996, 2003, and 2010. One WN human case and 94 equine cases with 42 deaths were reported in the first outbreak. The second and the last epizootics were in Kénitra and Mohammedia regions, respectively. Culex pipiens mosquitoes were strongly suspected as WN vectors during these epizootics in Morocco. To help propose the first insecticide resistance management strategy in Morocco, we provide baseline data on the resistance status of C. pipiens mosquitoes to insecticides most used in public health in Morocco. We investigated the resistance intensity of C. pipiens and the role of monooxygenases in pyrethroids resistance using the synergist piperonyl butoxide (PBO) in three prefectures of central Morocco: Mohammedia, Benslimane, and Skhirate. Bioassays were carried out using WHO (World Health Organization) diagnostic test kits for adult mosquitoes, with DDT 4%; deltamethrin 0.05%, 0.25%, and 0.5%; bendiocarb 0.1%, 0.5%, and 1%; and malathion 5%. The synergist PBO 4% was used to check for the involvement of detoxification enzymes in pyrethroids resistant populations. Mosquito populations tested displayed high resistance intensity to pyrethroids and carbamates in Mohammedia and moderate resistance intensity in Skhirate. In Benslimane, the resistance intensity of C. pipiens was high to carbamate and moderate to pyrethroids. The pre-exposure to PBO restored full or partial susceptibility to pyrethroids in the different regions. According to our finding, Mohammedia and Benslimane are at risk level 3 of control failure, while Skhirate is at risk level 2 of it. The employment of IRM is therefore imperative in all study sites. PubDate: Thu, 28 Apr 2022 10:50:03 +000
Abstract: Rapid development of resistance in vector mosquitoes to synthetic insecticides is a major challenge for malaria control. The use of plant-derived essential oils (EOs) is an attractive strategy in controlling mosquito populations because they are environmentally safe and may have a lower chance of developing resistance. This study assessed the larvicidal activities of EOs from Lantana camara, Lippia multiflora, Lippia chevalieri, and Cymbopogon schoenanthus against Anopheles funestus and Culex quinquefasciatus. The 3rd–4th instar larvae were tested using a World Health Organization (WHO)-modified protocol to evaluate larval mortality 24 h after exposure to EOs and their binary combinations. Culex quinquefasciatus larvae were more susceptible to EOs than An. funestus larvae. For Cx. quinquefasciatus, the lethal concentrations at 50% mortality (LC50s) of EOs from C. schoenanthus, L. multiflora, L. camara, and L. chevalieri were 23.32, 27.24, 38.54, and 54.11 ppm, respectively; whereas for An. funestus, the EO LC50s were 120.5, 67.5, 49.21, and 105.74 ppm, respectively. Synergistic effects were observed using EOs from C. schoenanthus + L. multiflora (LC50 = 44.05 ppm) on An. funestus, while L. camara + L. chevalieri (LC50 = 33.16 ppm), L. chevalieri + C. schoenanthus (LC50 = 12.08 ppm), and L. multiflora + L. chevalieri (LC50 = 20.61 ppm) were synergistic for Cx. quinquefasciatus. These results indicate the potential of EOs derived from local plants and their binary combinations as botanical larvicides. The EOs could be used as future ecofriendly agents to control these vectors. PubDate: Tue, 08 Mar 2022 06:35:01 +000
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