Showing papers on "Lepidoptera genitalia published in 2021"

Overview of Pest Status, Potential Risk, and Management Considerations of Helicoverpa armigera (Lepidoptera: Noctuidae) for U.S. Soybean Production

Abstract: Since its introduction and establishment in Brazil in 2013 and subsequent spread through most of Latin America, the Old World bollworm, Helicoverpa armigera (Hübner), has become an economically important pest of soybean, cotton, and other crops. Because this pest can migrate long distances aided by wind currents, it is expected to arrive and establish in the United States. There were reports of H. armigera moth incursions collected in pheromone traps from Puerto Rico and Florida, but no reports yet of field establishment in the United States. Although H. armigera is a polyphagous pest and poses threats to multiple crops, it has shown preference for and is considered a key pest of soybean and cotton in Brazil. Soybean and cotton in Mid-Southern states will be at greater risk for economic loss when this pest establishes in the United States due to similarities of H. armigera with the native sibling species, Helicoverpa zea (Lepidoptera: Noctuidae) (Boddie). Both are polyphagous, could damage the same crops, and have documented cases of resistance. Establishment of H. armigera in the United States presents uncertainty about how the two species may interact in U.S. agroecosystems. Management strategies for H. armigera consist of correct species identification, monitoring and early detection, and determining the susceptibility of populations to multiple control tactics to deploy effective management tools. Although it is expected to be a key pest of soybean and cotton, in this article, we discuss the overview of the potential threats which H. armigera poses to soybean production in Mid-Southern states when it establishes in the United States.

Damage characteristics and distribution patterns of invasive pest, Spodoptera frugiperda (J.E Smith) (Lepidoptera: Noctuidae) on maize crop in Bali, Indonesia

Abstract: Supartha IW, Susila IW, Sunari AAAAS, Mahaputra IGF, Yudha IKW, Wiradana PA. 2021. Damage characteristics and distribution patterns of invasive pest, Spodoptera frugiperda (J.E Smith) (Lepidoptera: Noctuidae) on maize crop in Bali, Indonesia. Biodiversitas 22: 3378-3387. The Fall Armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae) is a destructive crop pest native to North and South America which has now been reported to have spread to Indonesia. This study aims to ensure the attack and spread of invasive pests FAW on corn crops in Bali Province, Indonesia. In addition, it also studied population structure, age structure, and percentage of attacks on maize crops in high altitude areas in Bali. The research was conducted using survey methods. A sampling of plants is carried out in all districts and cities in the Bali by diagonal sampling. The sample unit size is 5 m × 5 m with the number of plants observed being 150 plants. The score of plant damage at the age of 4 weeks after planting (WAP) plants has a \"very heavy\" attack intensity value. Areas of upper leaves or young leaves most affected by S. frugiperda attack in the field. The results showed that pest FAW has been entering and attacking maize crops in Bali since January 2020 as the first report. At the beginning of the entry was only found in some lowland locations, especially in Tabanan and Jembrana regency, but within the next 4 months, it has spread evenly in all districts and cities in Bali. Adults populations and egg groups of FAW were found to peak by the time the corn crop was 2 weeks old after planting while the larval population reached its peak by the time the plant was 4 WAP The highest percentage of FAW attacks is in altitude areas below 250 meters above sea level (masl) with an average attack per observation plot of 47.84%. This research is the first to report on FAW attacks on maize crops in Bali since January 2020 and adds to our knowledge of FAW pests on maize crops in Bali.

The Circadian Clock in Lepidoptera

Abstract: With approximately 160,000 identified species of butterflies and moths, Lepidoptera are among the most species-rich and diverse insect orders. Lepidopteran insects have fundamental ecosystem functions as pollinators and valuable food sources for countless animals. Furthermore, Lepidoptera have a significant impact on the economy and global food security because many species in their larval stage are harmful pests of staple food crops. Moreover, domesticated species such as the silkworm Bombyx mori produce silk and silk byproducts that are utilized by the luxury textile, biomedical and cosmetics sectors. Several Lepidoptera have been fundamental as model organisms for basic biological research, from formal genetics to evolutionary studies. Regarding chronobiology, in the 1970s Truman's seminal transplantation experiments on different lepidopteran species were the first to show that the circadian clock resides in the brain. With the implementation of molecular genetics, subsequent studies identified key differences in core components of the molecular circadian clock of Lepidoptera compared to the dipteran Drosophila melanogaster, the dominant insect species in chronobiological research. More recently, studies on the butterfly Danaus plexippus have been fundamental in characterizing the interplay between the circadian clock and navigation during the seasonal migration of this species. Moreover, the advent of Next Generation Omic technologies has resulted in the production of many publicly available datasets regarding circadian clocks in pest and beneficial Lepidoptera. This review presents an updated overview of the molecular and anatomical organization of the circadian clock in Lepidoptera. We report different behavioral circadian rhythms currently identified, focusing on the importance of the circadian clock in controlling developmental, mating and migration phenotypes. We then describe the ecological importance of circadian clocks detailing the complex interplay between the feeding behavior of these organisms and plants. Finally, we discuss how the characterization of these features could be useful in both pest control, and in optimizing rearing of beneficial Lepidoptera.

Museomics: Phylogenomics of the Moth Family Epicopeiidae (Lepidoptera) Using Target Enrichment

Abstract: Billions of specimens can be found in natural history museum collections around the world, holding potential molecular secrets to be unveiled. Among them are intriguing specimens of rare families of moths that, while represented in morphology-based works, are only beginning to be included in genomic studies: Pseudobistonidae, Sematuridae, and Epicopeiidae. These three families are part of the superfamily Geometroidea, which has recently been defined based on molecular data. Here we chose to focus on these three moth families to explore the suitability of a genome reduction method, target enrichment (TE), on museum specimens. Through this method, we investigated the phylogenetic relationships of these families of Lepidoptera, in particular the family Epicopeiidae. We successfully sequenced 25 samples, collected between 1892 and 2001. We use 378 nuclear genes to reconstruct a phylogenetic hypothesis from the maximum likelihood analysis of a total of 36 different species, including 19 available transcriptomes. The hypothesis that Sematuridae is the sister group of Epicopeiidae + Pseudobistonidae had strong support. This study thus adds to the growing body of work, demonstrating that museum specimens can successfully contribute to molecular phylogenetic studies.

Insects as Food and Feed

Abstract: Insects currently represent 70–75% of all animal species living on earth (Katayama et al. 2007). The class of invertebrates Insecta of the phylum Arthropoda consists of over one million known species, while approximately five million species are in fact thought to exist in total. There are currently about 23 different insect orders, amongst which Coleoptera (beetles), Diptera (flies), Hymenoptera (bees, ants and wasps), Lepidoptera (butterflies and moths) and Orthoptera (crickets and grasshoppers) (Evans et al. 2015).

Developmental stage variation in Spodoptera frugiperda (Lepidoptera: Noctuidae) low temperature tolerance: implications for overwintering

Abstract: The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae) is a very destructive polyphagous insect pest of cereal crops accounting for up to 100% yield losses. To survive winter low temperatures in the Americas, adults FAW are known to migrate south for warmer climates and then re‐invade northern USA and Canada the following summer. Since its African invasion, no studies have looked at its overwintering biology. Specifically, there is no information on in situ ontogenetic low temperature tolerance, despite its significance in explaining overwintering survival. Here, we thus investigated low temperature tolerance of FAW larvae (3rd, 4th, 5th and 6th) and adults from field populations through assessing basal stress tolerance (critical thermal minima [CTmin], supercooling point [SCP] and chill coma recovery time [CCRT]) and plasticity using standardized protocols. Our results showed significant life stage effects on low temperature tolerance, although all were chill‐susceptible. Adults had lower CTmin and CCRT than larvae (higher cold tolerance). However, early instar larvae had significantly depressed SCPs than later instars and adults. All larval instars tested showed no plastic responses to CTmin, while for adults, cold hardening appeared to come at a cost of CTmin. These results suggest ontogenetic differences in S. frugiperda cold hardiness albeit all are susceptible to chilling. Second, the absence or cost of hardening confirms FAW's maladaptation to low temperatures. However, Botswana microclimate records show that severe low temperature stress is limited, and thus, in situ overwintering is possible. These results are important in developing informed pest management options for effective management of FAW in Africa.

Seasonal dynamics and spatial distribution of lepidopterans in selected locations in Mordovia, Russia

Abstract: . Ruchin AB. 2021. Seasonal dynamics and spatial distribution of lepidopterans in selected locations in Mordovia, Russia. Biodiversitas 22: 2569-2575. The research was conducted in 2019-2020 in the Republic of Mordovia (European part of Russia). In order to collect Lepidoptera, beer traps were used where beer served as bait. The field surveys were carried out from April to October in various forest habitats. The air temperature was recorded. To elucidate the spatial distribution of Lepidoptera, various habitats were examined in two study plots. In total, more than 23 thousand Lepidoptera specimens were examined. The largest number of Lepidoptera was collected in oak forests in contrast to the four other forest habitats. In all habitats, population dynamics were similar and characterized by the same trends of decrease and increase. During the season, there were three peaks of abundance for this group. A moderate first peak was recorded in the second half of May, while the maximum peak occurred in the first half of July. Autumn population peaks depend on temperature, while spring and summer peaks are associated with the flight of imagos and an increase in the lepidopteran abundance in habitats. In open habitats, the abundance of Lepidoptera was lower. On forest edges, the number of Lepidoptera considerably exceeded one in open habitats (river sandbanks, willow thickets, forest glades, and floodplain meadows) and closed habitats (inside the forests). Forest edges are a hotspot of Lepidoptera abundance and biodiversity in forest habitats. According to the vertical gradient, the number of lepidopterans was higher at the height of 7.5 m than at the height of 1.5 m. At the lower height, the number of Lepidoptera did not vary as considerably as at higher heights

An illustrated catalogue of the type specimens of Lepidoptera housed in the Zoological Museum Hamburg (ZMH): Part II. superfamily Papilionoidea

Abstract: We provide an updated catalogue of the type material of the lepidopteran superfamily Papilionoidea deposited in the Zoological Museum of Hamburg (ZMH). We report 414 specimens labelled as “types” belonging to nine species (all of valid names), 74 subspecies (44 valid names and 30 synonyms), 59 invalid infrasubspecific names under the ICZN code, and 23 specimens of 16 “in litteris” (= unavailable) names. Out of the 414 specimens labelled as “types”, 171 specimens are primary types (8 holotypes/lectotypes and 163 syntypes) and 80 are secondary types; 120 specimens are infrasubspecific and hence invalid and are considered as “original specimens”; and 43 specimens are treated here as “Non-type” specimens (topotype). We present a full bibliography of the original descriptions and illustrations for all of these taxa, aiming to provide a comprehensive taxonomic guide to this collection.

The mitochondrial genome of Qinghuang_1, the first modern improved strain of Chinese oak silkworm, Antheraea pernyi (Lepidoptera: Saturniidae)

Abstract: Chinese oak silkworm, Antheraea pernyi Guerin-Meneville 1855 (Lepidoptera: Saturniidae), is a traditional edible insect in China and is considered the edible insect with the highest potential. Info...

Preliminary characterisation of known pesticide resistance alleles in Spodoptera frugiperda (Lepidoptera: Noctuidae) in its invasive Australian range

Abstract: Fall armyworm (Spodoptera frugiperda) has recently been detected in Australia. Globally, S. frugiperda is reported to be resistant to insecticides, including those permitted for its control by the Australian Pesticides and Veterinary Medicines Authority. Consequently, an understanding of the insecticide resistance status of newly migrated S. frugiperda into Australia, as well as an ability to accurately identify newly hatched larvae, would facilitate sustainable management. To aid identification, we developed a real‐time polymerase chain reaction diagnostic assay that can identify S. frugiperda species, irrespective of life stage, and distinguish between the rice and corn strains. We then screened S. frugiperda individuals from Queensland, Western Australia, the Northern Territory and New South Wales for mutations causing target site insensitivity in the acetylcholinesterase (AChE) gene, the voltage‐gated sodium channel gene and the ryanodine receptor gene. In the populations tested, we found that mutation at positions A210S and F290V in AChE were common. These mutations are known to be associated with carbamate and organophosphate resistance in S. frugiperda outside Australia. In contrast, no mutation was found in gene voltage‐gated sodium channel causing pyrethroid resistance or the ryanodine receptor gene associated with diamide resistance. As S. frugiperda is new to Australia, the wide distribution of mutations in the AChE gene associated with organophosphate/carbamate resistance suggests that the original migrated S. frugiperda moths may have carried the mutations from outside Australia. As resistance genes have been detected, it is important to continue to monitor the resistance status of Australian S. frugiperda and further integrate complementary bioassay when available. Finally, as pesticide resistance is possible, it should be additionally considered when making pest management decisions and any spray failure should be followed by a pesticide from a different chemical group.

Moth (Insecta: Lepidoptera) fauna of Sariska Tiger Reserve, Rajasthan, India

Abstract: Survey to assess moth diversity was carried out in Sariska Tiger Reserve of Rajasthan in 2019 from June to November. Total 16 species were recorded under 15 genera, belonging to 5 families for the first time from Sariska Tiger Reserve. Of these, 12 species viz. Eudocima materna Linnaeus, 1767; Eudocima phalonia Linnaeus, 1763; Dysgonia stuposa (Fabricius, 1794); Euproctis divisia Walker, 1855; Achaea janata Linnaeus, 1758; Acherontia styx Westwood, 1847; Daphnis nerii Linnaeus, 1758; Hippotion rosetta (Swinhoe, 1892); Agrius convolvuli Linnaeus, 1758; Nephele hespera Fabricius, 1775; Theretra oldenlandiae (Fabricius, 1775); Caligula lindia Moore, 1865 were first time reports from the state. Moth species were collected with the help of a light sheet system operated every night from 9:00 pm to 2:00 am. Ethyl acetate fumes were used to kill collected speciemens and processed as per standard strategies in Lepidopterology. The identification of moths was carried out with the help of identification keys, standard reference keys. Family Erebidae and Sphingidae are represented by six species each, followed by Saturniidae represented by two species, Noctuidae and Crambidae represented by one species each. This study will improve our understanding of Sariska’s biodiversity and be used to develop strategies for the conservation of moth diversity.

The immatures of Peridroma saucia (Hübner, [1808]) (Lepidoptera: Noctuidae) revisited: redescription of external morphology of Neotropical populations

Abstract: (Hubner, [1808]) or ‘variegated cutworm’ is a cosmopolitan owlet moth pest resilient and abundant in agroecosystems. However, the morphology of their immatures is only briefly described, and inform...

The coffee leaf miner, Leucoptera coffeella (Lepidoptera: Lyonetiidae): identification of the larval instars and description of male and female genitalia

Abstract: The coffee leaf miner Leucoptera coffeella (Guerin-Meneville & Perrottet) is a key pest in coffee producing countries. During their development, the larvae feed on the palisade parenchyma of the leaves, forming mines and necrotic areas. As a result, the photosynthetic area of the plant decreases, affecting coffee production. Despite the severity of the damage caused by coffee leaf miner (CLM), morphological aspects of the larval development and the adult genitalia remain unknown. This work presents the first morphological description of the four larval instars and the adult genitalia of L. coffeella. In each larval instar, we measured the Mean ± SD (mm) of the cephalic capsules (1st 0,14±0,03; 2nd 0,25±0,04; 3rd 0,32±0,03; 4th 0,42±0,03) and observed the following morphological details: primary setae, prolegs, crochets and ecdysial line of the cephalic capsule. In the adults, we show how to differentiate adult sexing and observed the sexual structures present in both genitalia: male - bulbus ejaculatorius, valva, gnathos and aedeagus, and female - ovipositor, sclerite and corpus bursae.

Effects of temperature, age and stage on testis development in diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae)

Abstract: In Lepidoptera, it is known that larval and pupal testes enlarge in volume and then decrease in size over various phases of the pupal stage. After adult emergence, testis shrinkage continues. In the present study, the effects of temperature, age and stage on testis development were investigated in the diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae). Laboratory experiments indicated that in the adult stage, testis shrank markedly with age and with increasing temperatures, when males were reared at 15, 20, 25 or 30 °C during the larval and pupal stages and then transferred to other temperatures. When kept at 15, 20, 25 or 30 °C throughout their entire life (larva, pupa and adult), the higher the temperature, the smaller the testis volume at any given adult age, indicating that larval and/or pupal rearing temperatures also affected testis development. Field experiments carried out in Tokyo showed that testis volume in wild adult males of diamondback moth was quite varied, suggesting that this population had both young and old males at each survey time. The lower the larval and pupal rearing temperature, the larger the adult, as measured by forewing length. Since larger adults tended to have larger testis at adult emergence, adult testis volume should be compensated based on the forewing length. Mating reduced the testis size. Our results suggest that adult age of diamondback moths in wild populations can be estimated roughly from the data on testis volume, temperature and forewing length.

Microsatellite variation in Helicoverpa gelotopoeon (Lepidoptera: Noctuidae) populations from Argentina

Abstract: Helicoverpa gelotopoeon (Dyar) (Lepidoptera: Noctuidae) is a polyphagous pest that has been reported causing damage in many agricultural crops such as soybean, chickpea and cotton. This species, together with Helicoverpa zea (Boddie), Helicoverpa armigera (Hübner) and Chloridea virescens (Fabricius), belongs to the Heliothinae complex of economic importance in Northwestern Argentina. Many species in the Heliothinae subfamily have developed resistance to insecticides and insecticidal proteins from Bacillus thuringiensis (Bt). Managing resistance to these control tactics in H. gelotopoeon is of high importance and dependant on knowledge of population genetics of this species. The objective of this study was to evaluate the genetic variability and structure of H. gelotopoeon populations from different host plants and geographic regions of Argentina. Towards this goal, six microsatellite loci were screened across 196 individuals. The results obtained revealed high genetic diversity and lack of clear structure among the populations of H. gelotopoeon studied. This genetic homogeneity between populations from different geographical regions and hosts could be attributed to the long‐range migratory capacity of Heliothinae and the generalist behaviour of H. gelotopoeon.

DNA barcoding and morphology reveal a new cryptic species of Nagiella (Lepidoptera, Crambidae, Spilomelinae) from Japan.

Abstract: Nagiella tristalis Matsui & Naka, sp. nov. is described from Japan, based on DNA barcoding and morphological evidence. The two species previously known from Japan, N. quadrimaculalis and N. inferior , are diagnosed. Photographs of adults, including male and female genitalia of the three species, are provided.

Fall Cankerworm (Lepidoptera: Geometridae), a Native Defoliator of Broadleaved Trees and Shrubs in North America

Abstract: The fall cankerworm, Alsophila pometaria (Harris), is a species endemic to North America that feeds on broadleaf trees and shrubs. Fall cankerworm is a generalist folivore and larvae feed on a wide range of deciduous trees and smaller woody plants. Common hosts include oak, maple, cherry, ash, apple, beech, and birch. This pest is prone to repeated outbreaks over large areas, can cause extensive defoliation throughout hardwood forest stands, and can be a public nuisance in developed or highly populated areas. Fall cankerworm defoliation can lead to reduced tree health and impact ecosystem function, carbon sequestration, wildlife habitat, and temperature regulation, especially in urban areas. Elevated populations often occur in areas where host trees are stressed or a high density of a preferred host species is present. Fall cankerworm management is often necessary due to their impacts on the local tree canopy and nuisance to the public. Tree banding and the use of the biological insecticide Bacillus thuringiensis (Bt) are the common management tactics used to reduce fall cankerworm populations. Here we review fall cankerworm distribution, life stages, host plants, damage, scouting and sampling procedures, management options, and discuss commonly associated and co-occurring defoliator species.

Tachinids associated with lepidopteran pests in agricultural crops in south-central region of Goiás, Brazil

Abstract: Lepidopterans are among the most important groups of pests for crops in central Brazil. Fortunately, there is a significant diversity of natural enemies acting in the natural regulation of these pests. Among them, the parasitoids of the family Tachinidae (Diptera) are often found parasitizing the larval phase of Lepidoptera pests in Brazilian agricultural crops. However, little is known about the diversity of these parasitoids in crops in central Brazil, which is one of the main grain-producing regions. Knowing the diversity of tachinid associated to lepidopteran pests is the first step to future studies on conservative and applied biological control. Therefore, we studied the existing diversity of this family of parasitoids associated with several species of lepidopteran pests in soybean and corn crops in the state of Goias (Brazil) and neighboring municipalities. Nine species of Lepidoptera larvae were collected, of which approximately 18.9% were parasitized by tachinids. We identified three species and 25 morphospecies of this parasitoid family, belonging to 14 genera and nine tribes from three of the four existing subfamilies of tachinid. Strong associations between some tachinid species and hosts species were observed, e.g., Archytas incertus (Tachinidae: Diptera) and Helicoverpa armigera (Noctuidae: Lepidoptera), Gonia sequax (Tachinidae: Diptera) and Spodoptera frugiperda (Noctuidae: Lepidoptera). These species have great potential to be studied as applied biological control agents. This is the first recorded occurrence of the genus Atactosturmia (Tachinidae: Diptera) and the species G. sequax in Brazil.

Bioactivity of azadirachtin against Scrobipalpa ocellatella Boyd. (Lepidoptera: Gelechidae) on sugar beet

Abstract: The use of environmentally friendly bio-pesticides is crucial for higher root and sugar yield in sugar beets. The economic importance of beet moth [Scrobipalpa ocellatella Boyd. (Lepidoptera: Gelechidae)] losses in the field and storage highlight the need for evaluation of appropriate, environmentally friendly methods for pest control. The aims of the present study were to i) assess azadirachtin (AZN) effects on the life cycle and activity of the pest, and ii) manage the beet moth on roots under laboratory conditions. For the experiments, the main concentrations were prepared on the basis of the field-recommended dose of this pesticide (1–1.5 l/1000 l water). The LC50 was estimated for 3rd instar larvae. Later, at sublethal concentrations, the relative time for the emergence of each developmental stage was determined. The mean female fecundity was 37% (±4) for treated tests at the lowest AZN concentration (0.5 ml · l–1). Assess azadirachtin at 0.5 ml · l–1 concentration resulted in 62 (±4) deposited eggs per plant for the treated roots and 326 (±1) for roots in the control test. Mortality increased in response to increased AZN concentrations. The results revealed that after 72 h, the highest AZN concentration (2.5 ml · l–1) caused 100% repellency and 82% (±1.38) mortality on 3rd instar larvae. According to our findings, a concentration of 2 ml · l–1 AZN (20 gr active ingredient per 1 hectare) after 4 days affected 1st instar larvae and the larvae with no further development had 92.2% (±1.2) mortality. In conclusion, the results revealed that AZN as a biorational pesticide can significantly minimize the losses of S. ocellatella on sugar beet crops.

Fungi Recorded on Folivorous Lepidoptera: High Diversity Despite Moderate Prevalence.

Abstract: The knowledge about the diversity and ecological role of entomopathogenic fungi is primarily based on agroecosystems whereas information derived from natural insect populations is much more limited. To contribute to filling this gap, we recorded the prevalence of fungal infections in laboratory rearing experiments with five species of Lepidoptera, and in a field rearing experiment including one of these moths. The diversity of detected fungi was found to be high; we isolated 25 species of fungi from insects that had died in the course of these experiments. Six species belonged to the family Cordycipitaceae known to include unambiguous insect pathogens. The trophic niche of the representatives of other taxa is less clear and requires further studies. Regarding the most abundant species, Cordyceps farinosa, in which this question could be addressed, there was no indication of specialization on particular insect hosts, whereas several of the less common species may have been recorded from lepidopteran hosts for the first time. Across the subsets of the data, the prevalence of fungal infections generally remained below 5%. Our results are thus consistent with the idea that entomopathogenic fungi are always present in insect populations but rarely reach epizootic levels. The detected species richness shows that much is to be gained from mapping the diversity of fungal species associated with folivorous insects in natural populations.

The use of several maize varieties by farmers and the infestation of Spodoptera frugiperda (Noctuidae: Lepidoptera)

Abstract: The use of plant varieties can affect the presence and extent of pest attacks. Resistant varieties will cause a lower attack rate compared to susceptible varieties. It is not yet known which varieties of maize are resistant to Fall armyworm (S. frugiperda) (FAW) in the field, because this pest is an invasive pest and entered Indonesia one year ago. Research has been carried out to study the distribution, population, and level of S. frugiperda attack on maize varieties planted by farmers in the field. The research was conducted at the first location this pest was reported in West Pasaman district, West Sumatra, Indonesia. Survey on farmers’ corn with a sampling method: purposive random sampling. Samples were taken from different varieties of corn and showed signs of S. frugiperda attack. Observations were made on the varieties planted by farmers, symptoms, larvae population, and S. frugiperda attack rate. The results of the observations were that several trademarks of maize varieties grown by farmers were: Pioneer 32, Pertiwi, Bisi 18, NK7328, and NK212. The symptoms of this pest attack were the same for all varieties of maize, while the attack rate was significantly different at the 5% level. The attack rate ranged from 6.0 to 96.0%. The lowest attack percentage was on variety Bisi18, and the highest was on variety NK212. The population of S. frugiperda larvae was found in all varieties of maize with an average of 0.70 larvae per stem.

New subdivision of cotton production area of Côte d’Ivoire based on the infestation of main arthropod pests

Abstract: Variations in populations of arthropod pests, under the influence of climate change, compromise the effectiveness of the cotton phytosanitary protection strategy in Cote d'Ivoire. This study aims to establish a new classification of cotton production areas, on the basis of predominant pests. A monitoring was therefore carried out from 2016 to 2019 in 400 farmers' fields. In these fields, surveys were conducted weekly, from the 30th to the 122nd day after emergence. Data analysis, through Principal Component Analysis, identified four groups of localities. The first group includes the northeastern localities (4°W to 5°W: 8°N to 10.5°N) such as Kong, Ouangolodougou, Sordi, Tiekpe, Kaouara. This area is characterized by high infestations of most pests (jassid, white flies, exocarpic lepidoptera, endocarpic lepidoptera, phyllophagous lepidoptera and mites). The second group is intermediate between northeast and central (5.5°W to 6.2°W: 8.3°N to 10.5°N). This area is characterized by infestations of jassid, white flies and exocarpic lepidoptera (H. armigera and D. watersi). It remains less infested by endocarpic lepidoptera (T. leucotreta and P. gossypiella). The third area is located in the South (4.5°W to 8.5°W: 6°N to 8.5°N). It is essentially infested by endocarpic lepidoptera T. leucotreta and P. gossypiella. Jassid and whitefly infestations are less important in this part, compared to the northern part. The fourth and last area extends from the center to the west (6°W to 8°W: 8°N to 10.5°N). Pest infestations are lower in this area compared to other areas.

The effectiveness of Samia ricini Drury (Lepidoptera: Saturniidae) and Attacus atlas L. (Lepidoptera: Saturniidae) cocoon extracts as ultraviolet protectants of Bacillus thuringiensis for controlling Spodoptera litura Fab. (Lepidoptera: Noctuidae)

Abstract: Bacillus thuringiensis var. kurstaki (Bt.) is a bioinsecticide that is often used as an alternative for controlling tobacco cutworm, Spodoptera litura Fab. (Lepidoptera: Noctuidae). However, this bioinsecticide might easily degraded by ultraviolet (UV) from the sun light. This study aimed to determine the effectiveness of eri, Samia ricini Drury (Lepidoptera: Saturniidae) and atlas moth, Attacus atlas L. (Lepidoptera: Saturniidae) cocoon extracts as UV B protectants for Bt. against the larval stage of tobacco cutworm. Cocoon extracts of 0, 0.5, 1, 2, and 2.5% of eri and atlas sericin was added respectively to make Bt. suspensions at 10LC95 (2 × 108 spores/ml). After that, the suspensions then exposed under UV B lights at laboratory conditions for 1, 2, 3, and 4 weeks. Then, the pathogenicity was tested against 25 individuals of 1st larval instar of tobacco cutworm using three replicates. The results showed that the mortality percentage of tobacco cutworm treated with cocoon added Bt. were significant difference compared to Bt. alone. At the 1st week of UV B exposure, the mortality of tobacco cutworm in Bt. alone, Bt. + eri, and Bt. + atlas was 31.67, > 90, and > 75% respectively. Whereas, at the 4th week, the mortality of each treatment was 46.67, > 81, and > 75% respectively. The pathogenicity results implied that the addition of eri and atlas silk moths cocoon extracts significantly improved the Bt. toxicity by 1.75 – 1.86 and 1.6 – 2.1 fold, respectively, even after four weeks of UV B exposure. Based on this research, it can be concluded that the addition of eri and atlas silk moths sericin extracts show high potential for the UV B protectants for Bt. to enhance its persistence for future formulations.