Pest In Africa Research Articles

Compatibility of synthetic and biological pesticides with a biocontrol agent Phytoseiulus longipes (Acari: Phytoseiidae)

Phytoseiulus longipes is a predatory mite of Tetranychus evansi, which is an invasive pest in Africa and elsewhere. The introduction of this predator in Africa has considerable potential, but little is known about the compatibility of P. longipes with commonly used pesticides. Here, we examined lethal and sublethal effects of two pyrethroids (cypermethrin and deltamethrin), two organophosphates (dimethoate and chlorpyrifos), one nicotinoid (imidacloprid), two acaricides (propargite and abamectin), two naturally derived pesticides (oxymatrine and azadirachtin), and one entomopathogenic fungal-based formulation (Hirsutella thompsonii) on P. longipes eggs and adults. The pesticides were sprayed at their maximum recommended concentrations. Topical exposures to azadirachtin, imidacloprid, propargite, abamectin, oxymatrine, and H. thompsonii significantly reduced the net reproductive rate (R0), intrinsic rate of increase (r) and finite rate of increase (λ)of P. longipes. Pesticide lethal and sublethal effects on the predator were summarized in a reduction coefficient (Ex) for the classification based on IOBC toxicity categories. Results revealed that Azadirachtin and H. thompsonii were slightly harmful effects to adults. Imidacloprid, propargite, abamectin, and oxymatrine were moderately harmful to both eggs and adults. Residual persistence bioassays revealed that 4-day-old residue of azadirachtin had no harmful effect on the predator. Abamectin, oxymatrine, and H. thompsonii became harmless to it 10 days post-spraying, and propargite and imidacloprid were considered harmless after 20 days. Cypermethrin, deltamethrin, dimethoate, and chlorpyrifos were highly harmful to both eggs and adults, persistence remaining high even after 31 days of application. These findings provide valuable insights into decision-making when considering P. longipes for use in IPM programs.

Impact of Spodoptera frugiperda (Lepidoptera: Noctuidae), on maize yield in humid tropical zones of Central Africa.

Fall armyworm, Spodoptera frugiperda Smith, became the most important maize pest in Africa in 2016, with management based on chemical pesticides. High yield losses across the continent were predicted based on farmers' perceptions, but existing agroecological differences were not considered. In the Democratic Republic of Congo, experiments were conducted to assess fall armyworm damage and yield losses in maize farms with and without treatment. The study included 2 seasons in the Kipopo wetland in 2020 and 2021, one rainy season in Kanyameshi in 2021, 2 rainy seasons in Mulungu in 2020 and 2021, and one season in a wetland on the Bishibiru site in 2020. In addition, the research was also conducted at 4 sites in Cameroon from September to December 2020 and from March to July 2021. High levels of damage incidences were recorded, but the density of larvae per plant was low, with low to moderate levels of damage severities in different seasons and sites. Treatment significantly reduced the number of fall armyworm larvae and their damage severity. However, the high infestation levels did not significantly reduce yield. Cost-benefit ratios were either negative or, in most cases, less than 1. In the best case, the use of pesticides only allowed the recovery of the amount used for the intervention. We discussed the implications of these findings for fall armyworm management in humid tropical agroecology.

Occurrence and Pathogenicity of Indigenous Entomopathogenic Fungi Isolates to Fall Armyworm (Spodoptera frugiperda J. E. Smith) in Western Amhara, Ethiopia

The fall armyworm (FAW) (Spodoptera frugiperda J. E. Smith) is widely recognized as an invasive lepidopteran pest in Africa. Adoption of synthetic pesticides remains an option for emergency control of the FAW, but their large-scale use by small-scale farmers is costly and environmentally unsafe. Management options based on entomopathogenic fungi could minimize risks for health and the environment. In our study, the occurrence of entomopathogenic fungi in different habitats along with their pathogenicity to fall armyworm was examined. A total of 56 soil samples were collected from three locations. A standard isolation method, baited with the wax moth larvae (Galleria mellonella), was used for the isolation of entomopathogenic fungi from soil. Twelve entomopathogenic fungi were isolated from the total soil samples collected. It was observed that Metarhizium spp. was more frequent and widespread than Beauveria spp. and their occurrence was high in the forest habitat. Pathogenicity of indigenous entomopathogenic fungi isolates on fall armyworm larvae was tested by applying conidial suspension containing 1 × 108 spores/ml. All of the isolates tested were pathogenic to larvae of fall armyworm, with mortalities varying from 30 to 80% at 10 days posttreatment. Our results suggest that native entomopathogenic fungi could be integrated for the management of Spodoptera frugiperda larvae.

Studies on Nutrition, Utilization and Hosts Preference of Feeding Fall Armyworm Larvae, Spodoptera frugiperda on Some Vegetable Crops Leaves

Ouda, M.I. 2024. Studies on Nutrition, Utilization and Hosts Preference of Feeding Fall Armyworm Larvae, Spodoptera frugiperda on Some Vegetable Crops Leaves. Arab Journal of Plant Protection, 42(3): 269-274. https://doi.org/10.22268/AJPP-001259 The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith, 1797) (Lepidoptera: Noctuidae), appeared in 2016 on maize crop in the Americas. Thereafter, it was recorded as an invasive pest in Africa during 2017. In Egypt, this study was conducted during 2022 to investigate the nutritional indices and host preference of the 3rd and 5th instars of FAW larval stage on fifteen vegetable crops under laboratory conditions. Experiments were conducted under constant temperature in an incubator at 27±1°C, relative humidity of 65±5% and a photoperiod of 14:10 hrs (light: dark). The results obtained showed that the hosts Beta vulgaris L., Cichorium intybus L., Fragaria x ananassa L., Brassica rapa L. and Zea mays L. var. everta were significantly favoured as primary hosts for FAW development. These hosts had higher larval and pupal weight and feeding indices: consumption index (CI), approximate digestibility (AD), efficiency of conversion of ingested food into body matter (ECI), efficiency of conversion of digested food into body matter (ECD) and relative growth rate (RGR). Whereas the hosts Vigna unguiculata, Lactuca sativa, Brassica oleracea var. capitata, Brassica oleracear var. botrytis, Eruca vesicaria subsp. sativa, Pisum sativum and Vicia faba were favored as secondary hosts for FAW development, with lower values for larvae and pupae weight and feeding indices. However, the larvae did not prefer and did not complete feeding on the hosts Cucumis sativus, Solanum lycopersicum and Phaseolus vulgaris. Keywords: Spodoptera frugiperda, biology, nutritional indices, host preference.

Impact of Cowpea-maize Intercropping and Bio-rational Product on Fall Armyworm, Spodoptera frugiperda (JE Smith) in Fodder Maize

Background: A recent occurrence of fall armyworm (FAW), Spodoptera frugiperda (JE Smith) a new invasive pest in Africa attained epidemic form in 2016. Consequently, researchers probed various ecofriendly methods to manage the pest. The effect of intercropping cowpea [Vigna unguiculata (L.) Walp.] with fodder maize (Zea mays L.) on the incidence of FAW was investigated. Methods: The maize fodder was protected against FAW by intercropping with cowpea along with a biorational product, Brahamastra and compared with the recommended insecticide used to manage the insect by conducting field experiments during kharif 2020, 2021 and 2022 comprising the eight treatments viz. T1: Maize + Cowpea 1:1 ratio (unsprayed); T2: Maize + Cowpea 1:1 ratio (coragen @ 100 ml ha-1); T3: Maize + Cowpea 1:1 ratio (brahamastra @ 12.5 litre ha-1 sprayed); T4: Maize sole (brahamastra @ 7.5 litre ha-1 sprayed); T5: Maize sole (brahamastra @ 10.0 litre ha-1 sprayed); T6: Maize sole (Brahamastra @ 12.5 litre ha-1 sprayed); T7: Maize sole (coragen 18.5 SC @ 100 ml ha-1 sprayed as standard check) and T8: Maize sole (Unsprayed). The plot size for each treatment was 500 m2, demarcating 5 ´ 4 m2 for sampling with three replications in a completely randomized design (CRBD). Result: The treatments, Maize + Cowpea (1:1 row) (Coragen @ 100 ml ha-1 sprayed) and Maize sole (Coragen @ 100 ml ha-1 sprayed) though had significantly the lowest pooled pest incidence and the highest per cent reduction over control (PROC), the bio-rational applied on maize + Cowpea (1:1 row) (brahamastra @ 12.5 litre ha-1 sprayed) encounted the lowest pest incidence, the highest PROC combined with the highest fodder yield and economic returns without any statistical singnificant difference with Maize + Cowpea (1:1 row) (unsprayed).

The History of Baculovirology in Africa.

Baculovirology has been studied on the African continent for the development of insect virus-based biopesticides and, to a much lesser extent, vaccine production and delivery, since the 1960s. In this review, we focus only on baculoviruses as biopesticides for agricultural pests in Africa. At least 11 species of baculovirus have been discovered or studied on the African continent, some with several distinct isolates, with the objective in most cases being the development of a biopesticide. These include the nucleopolyhedroviruses of Helicoverpa armigera, Cryptophlebia peltastica, Spodoptera exempta, Spodoptera frugiperda, Spodoptera littoralis, and Maruca vitrata, as well as the granuloviruses of Cydia pomonella, Plutella xylostella, Thaumatotibia (Cryptophlebia) leucotreta, Choristoneura occidentalis, and Phthorimaea operculella. Eleven different baculovirus-based biopesticides are recorded as being registered and commercially available on the African continent. Baculoviruses are recorded to have been isolated, researched, utilised in field trials, and/or commercially deployed as biopesticides in at least 13 different African countries. Baculovirus research is ongoing in Africa, and researchers are confident that further novel species and isolates will be discovered, to the benefit of environmentally responsible agricultural pest management, not only in Africa but also elsewhere.

Assessment of the effects of climate change on the occurrence of tomato invasive insect pests in Uganda

The shift in the geographical spread of invasive pests in Africa has rarely been linked directly to climate change. However, it is predicted that environmental changes play a significant role in spreading and expanding pests. The occurrence of new tomato invasive insect pests has been increasing in Uganda during the past century. Assessing the impact of temperature, rainfall, relative humidity, and windspeed on the occurrence of invasive tomato insect pests, gives a better understanding of managing and limiting the bio-invasion process sustainably. We used the Mann Kendall trend Test to establish trends in climate variables from 1981 to 2020 and to document the trend in the occurrence of new invasive pests. The relationship between climate variables and pests occurrence is analyzed using Pearson's correlation and the Generalized Linear Model (GLM-quasi-Poisson) in R-software. The results showed that temperature and windspeed have significantly increased in both Kampala and Namutumba by 0.049 °C, 0.005 m s−1and by 0.037 °C, 0.003 m s−1 per year respectively while in Mbale there was no change in wind speed pattern and a non-significant decrease in temperature. There was an overall rainfall increase in Kampala (p = 0.029) by 0.241 mm, Mbale (p = 0.0011) by 9.804 mm, and Namutumba (p = 0.394) by 0.025 mm. On the other hand, humidity has decreased both in Kampala (p = 0.001) by 13.3% and in Namutumba (p = 0.035) by 13.2% while there was a no significant change in Mbale. The results of GLM showed that each variable, taken individually, had a direct effect on the pests' occurrence in all three districts. However, with all these climate variables taken together, the effect on the pests' occurrence varied with each of the three districts; Kampala, Mbale, and Namutumba. This study demonstrated that pest occurrence is different from one agroecology to another. Our findings suggest that climate change is a driver that favors bio-invasion of tomato invasive insect pests occurrence in Uganda. It calls for awareness to policymakers and stakeholders to consider climate-smart pest management practices and policies to deal with bio-invasion.

Classical biological of key horticultural pests in Africa: successes, challenges, and opportunities.

Classical biological control (CBC) is considered a safer and more sustainable alternative for management of alien-invasive species. This review presents recent advances in CBC of key horticultural insect pests using parasitoids in Africa. Several CBC programs have been undertaken targeting different insect pests of both fruits and vegetables, largely yielding outstanding success. Key obstacles impeding CBC and opportunities that could promote CBC in Africa are outlined. Also, very brief highlights on recent scientific and technological advances in modeling, integrative taxonomy and molecular tools, and endosymbionts that relate to CBC are provided.

Mitochondrial genetic diversity of the Greater Cane rat (Thryonomys swinderianus) populations from the Eastern Arc Mountains ecosystem, Tanzania.

Management of most herbivorous small mammal species considered to be pests in Africa is still challenging partly because of the paucity of information on their biological traits that would help to manage their destructive impacts. This gap also precludes the potential for tapping species with potential food-value to improving the economy of rural communities through, for example, sustainable game farming programs in Africa. This study investigates the genetic diversity and population demography of the African Greater Cane rat (AGC), a rodent pest of crops and game species inhabiting two isolated blocks of the Eastern Arc Mountains (EAMs), Tanzania to contribute to the species management and conservation. We used non-invasive sampling techniques and DNA sequencing of the D-loop region of MtDNA (515bp) from 46 cane rats (Thryonomys swinderianus) samples to characterize the genetic diversity and structure of the species and potential population threats faced in natural habitats. We found 25 haplotypes:15 from Uluguru and 9 from Udzungwa mountains populations, containing 49 polymorphic regions (32 parsimoniously informative and 17 singleton sites). Haplotype diversity (range: 0.849-0.995) did not differ substantially across populations but the median haplotype diversity for Udzungwa South was overall lower than for other populations. Nucleotide diversity averaged 0.00641, 0.01528, 0.0111 and 0.01313, respectively for Udzungwa South, Udzungwa North, Uluguru Rural and Uluguru Urban, suggesting high genetic diversity within the four populations. Analysis of molecular variance (AMOVA) indicated significantly high genetic differences between the four populations (FST = 0.16, p = 0.00098) whereas neutrality test (FU's Fs) values were negative, indicating historical population expansion. Similarly, the Bayesian skyline analysis indicated a recent demographic expansion suggesting limited bottlenecks in the recent past in this population. Our results show the AGC population in EAMs consists of four distinct populations which have experienced a recent population expansion, especially among the urban population due perhaps to influence of urbanization process that may have favored assisted species movements across the rural-urban landscapes. Future research should focus on understanding impact of geographical isolation on the genetic structure and diversity of this species.

Identification of entomopathogenic fungus Metarhizium rileyi infested in fall armyworm in the cornfield of Korea, and evaluation of its virulence.

The fall armyworm (FAW) Spodoptera frugiperda is an important invasive pest in Africa and Asia. It is a polyphagous pest with at least 353 recorded host plant species, including corn. Chemical control of this pest is unsuccessful because of a developed resistance and harmful effects on the environment. Entomopathogenic fungi are potential biological control agents for FAW. In this study, the native strain of Metarhizium rileyi (KNU-Ye-1), collected from a cornfield at Yeongcheon, Korea, was identified by morphological and molecular characterization. The susceptibility of the fourth-instar larvae of FAW to the native strain M. rileyi was examined in the laboratory. The results showed that the Korean strain of M. rileyi (KNU-Ye-1) was highly virulent to FAW larvae, causing 89% mortality 7 days posttreatment. Therefore, M. rileyi (KNU-Ye-1) identified in this study is highly valuable for the biological control of FAW in the field.

Biological control of pest cactus and cactus pests in Africa

Biological control of pest cactus and cactus pests in Africa

Literature Review on the Natural Enemies of Spodoptera Frugiperda J. E. Smith (Lepidoptera: Noctuidae) and the Effectiveness of Their Use in the Management of This Pest in Corn (Zea Mays L.)

The fall armyworm Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) is an important maize pests that threaten food security in sub-Saharan Africa. In order to evaluate the diversity of natural enemies and especially their effectiveness for a sustainable management of this pest in Africa, a literature review was carried out. It consisted in exploiting 35 scientific publications from the most highly rated journals, over the period 2015-2020 relating to the inventory of the natural enemies of S. frugiperda and their effectiveness in the world in general and more particularly in Africa. It emerges from this study that there is a large diversity of natural enemies of S. frugiperda in the world. In total, 66 species of natural enemies belonging to 21 families in 10 orders have been recorded. Parasitoids have been the most studied 43 (64.18%) and the most used in the control of S. frugiperda, followed by predators 13 (19.40%) and entomopathogens (13.42%). In Africa, 24 of the 67 species have been recorded in 9 countries. Parasitoids were also created with a rate of 26.86% or 75.00% at the African level. The main most effective parasitoids were Telenomus remus (Hymenoptera: Scelionidae), Chelonus insularis Cresson (Hymenoptera: Braconidae) and Cotesia marginiventris Cresson (Hymenoptera: Braconidae) with parasitism rates varying between 0.85 and 9.90% depending on the environments. In view of the results, since these species have been listed in Africa, they seem to be real candidates for future programs for the sustainable management of this caterpillar. Research is underway in Togo and probably in the rest of the countries of the continent for a better knowledge and development of these natural enemies.

Approaches to conservation of Nesidiocoris tenuis for biological control of pests in field-grown tomato in Senegal

Conservation biological control is a promising approach to natural pest control in both open field and protected crops. In sub-Saharan Africa, tomato crops are commonly damaged by several arthropod pests but can also host the predatory mirid bug, Nesidiocoris tenuis. Unfortunately, farmers do not currently take full advantage of this zoophytophagous and generalist biocontrol agent. We conducted field investigations in the Niayes area of Senegal, combined with laboratory experiments, to determine how to enhance natural regulation services provided by this natural enemy. We found that strong full-plant watering and insecticidal sprays, both conventionally applied in the Niayes area, had a detrimental effect on N. tenuis. We identified Sesamum radiatum (false or black sesame) as a promising insectarium plant that could also serve as a leaf vegetable and medicinal plant. This plant supports good N. tenuis development and reproduction, even without alternative food sources. Y-tube olfactometry indicated no attraction to odors of Sesamum radiatum, suggesting that N. tenuis would not abandon tomato plants for this insectarium plants when present in tomato fields. Our results suggest potential approaches to improve conservation of N. tenuis for biological control of Tuta absoluta and other tomato pests in Africa.

Transgenerational responses to heat and fasting acclimation in the Angoumois grain moth

Transgenerational plasticity (TGP) is a physiological mechanism where environmental experiences of parents affect phenotypes of the offspring, and potentially facilitates organisms' survival in stressful environments. The Angouimois grain moth, Sitotroga cerealella (Olivier), is a dominant primary grain pest in Africa, particularly affecting sorghum and maize staples. Despite its widely known economic significance, little is known on its thermal responses, particularly how acclimation in one generation impacts fitness in successive generations. We tested how heat (acute and dynamic) as well as fasting acclimation in one generation affects physiological tolerance (i.e., critical thermal maxima [CTmax] and heat knock down time [HKDT]) using laboratory-reared S. cerealella populations. Specifically, we assessed whether pre-exposure to heat or fasting stress confers fitness costs or benefits in subsequent generations (i.e., through TGP). Results showed acclimation had significant effects in interaction with temperature ramping rates on CTmax. Moderate acute heat (34 °C) and dynamic temperature (28–38 °C) acclimations reduced F1 CTmax and HKDT, particularly at low ramping rates (for CTmax). We did not find fasting acclimation to significantly affect CTmax, indicating a lack of evidence for cross tolerance and/or susceptibility. For HKDT, all acclimation treatments (including fasting) showed significantly lower HKDT compared to controls, and mostly so, for the 38 °C and dynamic acclimation (28–38 °C) treatments, indicating a transgenerational fitness cost of acclimation. This is the first report of the costs of transgenerational plasticity in a stored product pest of economic significance and has implications in designing heat-based phytosanitary grain treatments.

Bioactive Volatiles From Push-Pull Companion Crops Repel Fall Armyworm and Attract Its Parasitoids

Fall armyworm, Spodoptera frugiperda, is a serious invasive pest in Africa but “Push-Pull” companion cropping can substantially reduce infestation. Here, we elucidate the underpinning chemical ecology mechanisms. We hypothesized that companion crop volatiles repel herbivores (push) while attracting natural enemies (pull). Headspace volatiles collected from companion plants (Desmodium intortum, Desmodium uncinatum, Brachiaria Mulato II) were used in bioassays and electrophysiological recordings with S. frugiperda and parasitoid wasps. Insect populations, plant damage and herbivore parasitism were assessed in field plots. Coupled GC-electroantennogram (GC-EAG) recordings showed robust responses to certain aromatic and terpenoid volatile compounds. In wind tunnel bioassays, maize volatiles mixed with Desmodium volatiles were less attractive to moths than maize alone. In oviposition bioassays, S. frugiperda laid significantly fewer eggs on maize when Desmodium volatiles were present. Conversely, in an olfactometer bioassay, parasitoid wasps were attracted to the scent of both Desmodium spp. (intercrop) and the Brachiaria border crop. Our data provide evidence of the mechanisms underpinning reduced S. frugiperda infestation in the Push-Pull companion cropping system, i.e., volatiles from companion crops repel S. frugiperda while attracting its parasitoid natural enemies. These findings explain why Push-Pull field plots had fewer S. frugiperda larvae and lower crop damage than monocropped maize.

First report of potential egg parasitoid Telonomus spp (Hymenoptera : Scelionidae), on invasive pest, Spodoptera frugiperda (J. E. Smith) in maize (Zea mays) from Indian subcontinent

The fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is an insect native to the tropical and subtropical Americas that has recently spread to Africa. where it predominately attacks maize, sorghum and other plant species. The fall armyworm, Spodoptera frugiperda, is a lepidopteran pest that feeds on many economically important cereal crops such as corn, rice, sorghum, and sugarcane. Native to the Americas, it has become a serious invasive pest in Africa and Asia. Biological control is an environmentally friendly way of combatting the pest and contributes to an integrated pest management approach. Thus studies on the occurrence of Fall Army Worm (FAW) S. frugiperda and its natural enemies were conducted during 2020–21 at MARS, Dharwad, Karnataka, India in fixed plots to record potential natural enemies on FAW in maize ecosystem. Egg mass collected was observed for the number of adult parasitoids that emerged from egg mass, and the percentage parasitisation were recorded. The present study reports new associations of natural enemies on fall armyworm in India with reference to the northern Karnataka. Study revealed that the egg parasitoid, Telonomus spp. (Hymenoptera: Scelionidae) was noticed; as potential egg parasitoid on FAW which accounted for 10–11% parasitisation at field level. Study on species level description is under process, specimen was collected has been sent to experts for their identification. Further identification of natural enemies and preserving the existing ones, through eco-friendly practices and judicial use of pesticides, allowing them to function effectively, which leads to effective management of FAW.

Development of a Species Diagnostic Molecular Tool for an Invasive Pest, Mythimna loreyi, Using LAMP.

Simple SummaryMythimna loreyi is a serious pest of grain crops and reduces yields in maize plantations. M. loreyi is a native species in East Asia for a long time. However, this species has recently emerged as a migration (or invasive from other Asian countries) pest of some cereal crops in Korea. Little is known about its basic biology, ecology, and it is difficult to identify the morphologically similar species, Mythimna separate, which occur at the cornfield in the larvae stage. Species diagnosis methods for invasive pests have been developed and utilized for this reason. Currently, the molecular biology method for diagnosing M. loreyi species is only using the mtCO1 universal primer (LCO1490, HCO2198) and process PCR and sequencing to compare the degree of homology. However, this method requires a lot of time and effort. In this study, we developed the LAMP (loop-mediated isothermal amplification) assay for rapid, simple, and effective species diagnosis. By analyzing the mitochondrial (mt) genome, the species-specific sequence was found at the coding region of the NADH dehydrogenase subunit 5 gene. A broad range of DNA concentration was workable in LAMP assay, in which the minimum detectable DNA concentration was 100 pg. DNA releasing method was applied, which took five minutes of incubation at 95 °C without the DNA extraction process, and only some pieces of tissue from larvae and adult samples were needed. The incidence of invasive pests is gradually diversifying. Therefore, this simple and accurate LAMP assay is possibly used in the intensive field monitoring for invasive pests and integrated management of Mythimna loreyi.The Mythimna loreyi (Duponchel) is one of the well-known invasive noctuid pests in Africa, Australia, and many Asian countries. However, it is difficult to identify the invasive and morphologically similar species, Mythimna separate, which occur at the cornfield in the larvae stage. Currently, the molecular biology method for diagnosing M. loreyi species is only using the mtCO1 universal primer (LCO1490, HCO2198), which requires a lot of time and effort, such as DNA extraction, PCR, electrophoresis, and sequencing. In this study, the LAMP assay was developed for rapid, simple, effective species identification. By analyzing the mitochondrial genome, the species-specific sequence was found at the coding region of the NADH dehydrogenase subunit 5 gene. Based on this unique sequence, four LAMP primers and two loop primers were designed. The F3 and B3 primers were able to diagnose species-specific, in general, and multiplex PCR and specifically reacted within the inner primers in LAMP assay. The optimal incubation condition of the LAMP assay was 61 °C for 60 min with four LAMP primers, though additional loop primers, BF and LF, did not significantly shorten the amplification time. The broad range of DNA concentration was workable in LAMP assay, in which the minimum detectable DNA concentration was 100 pg. DNA releasing method was applied, which took five minutes of incubation at 95 °C without the DNA extraction process. Only some pieces of tissue of larvae and adult samples were needed to extract DNA. The incidence of invasive pests is gradually diversifying. Therefore, this simple and accurate LAMP assay is possibly applied in the intensive field monitoring for invasive pests and integrated management of Mythimna loreyi.

Effect of entomopathogenic fungi introduced as corn endophytes on the development, reproduction, and food preference of the invasive fall armyworm Spodoptera frugiperda

Fall armyworm (FAW), Spodoptera frugiperda, is a migratory polyphagous pest that causes major damage to economically important cultivated grasses, such as corn. Native to the neotropics in America but recently reported as an invasive pest in Africa and Asia, FAW imposes a serious threat to food security and sustainable crop productivity due to lack of effective management. In this study, the introduction of entomopathogenic fungi as endophytes was explored as an alternative more sustainable management strategy against FAW in corn. The study determined (1) the effect of isolates and inoculation methods on the ability of entomopathogenic fungi to colonize corn plants, and (2) the effect of colonized plants on S. frugiperda survival, development, reproduction, and food preference. Although all tested isolates (twelve of Beauveria bassiana and one each of Metarhizium anisopliae and Metarhizium robertsii) colonized inoculated plants, there was a highly significant interaction between isolates and inoculation methods. Highest plant colonization was obtained by Beauveria bassiana isolate (LPSc 1098) using foliar spray. Endophytic B. bassiana caused significant reductions in larval and pupal survival, length of different developmental stages, total S. frugiperda lifespan, and leaf area consumed by third instar larvae. Plant colonization also significantly reduced female longevity, fecundity, and fertility. This is the first report for the negative effects of endophytic B. bassiana on S. frugiperda growth, reproduction, and food preference. Our results highlight the promising potential of incorporating entomopathogenic fungi as endophytes in integrated pest management practices to protect corn against FAW if their efficacy is also confirmed under field conditions.

Fall-armyworm invasion, control practices and resistance breeding in Sub-Saharan Africa.

Fall armyworm [Spodoptera frugiperda (J.E. Smith); FAW] invasion has exacerbated maize (Zea mays L.) crop yield losses in sub‐Saharan Africa (SSA), already threatened by other stresses, especially those that are climate‐change induced. The FAW is difficult to control, manage, or eradicate, because it is polyphagous and trans‐boundary, multiplies fast, has a short life cycle and migrates easily, and lacks the diapause growth phase. In this study, FAW and its impact in Africa was reviewed, as well as past and present control strategies for this pest. Pesticides, cultural practices, natural enemies, host‐plant resistance, integrated pest management (IPM), and plant breeding approaches were examined as possible control strategies. It was concluded that an IPM control strategy, guided by cultural approaches already being used by farmers, and what can be adopted from the Americas, coupled with an insect‐resistance management strategy, is the best option to manage this pest in Africa. These strategies will be strengthened by breeding for multi‐trait host‐plant resistance through stacking of genes for different modes of control of the pest.

KASP Genotyping as a Molecular Tool for Diagnosis of Cassava-Colonizing Bemisia tabaci.

Bemisia tabaci is a cryptic species complex that requires the use of molecular tools for identification. The most widely used approach for achieving this is the partial sequencing of the mitochondrial DNA cytochrome oxidase I gene (COI). A more reliable single nucleotide polymorphism (SNP)-based genotyping approach, using Nextera restriction-site-associated DNA (NextRAD) sequencing, has demonstrated the existence of six major haplogroups of B. tabaci on cassava in Africa. However, NextRAD sequencing is costly and time-consuming. We, therefore, developed a cheaper and more rapid diagnostic using the Kompetitive Allele-Specific PCR (KASP) approach. Seven sets of primers were designed to distinguish the six B. tabaci haplogroups based on the NextRAD data. Out of the 152 whitefly samples that were tested using these primer sets, 151 (99.3%) produced genotyping results consistent with NextRAD. The KASP assay was designed using NextRAD data on whiteflies from cassava in 18 countries across sub-Saharan Africa. This assay can, therefore, be routinely used to rapidly diagnose cassava B. tabaci by laboratories that are researching or monitoring this pest in Africa. This is the first study to develop an SNP-based assay to distinguish B. tabaci whiteflies on cassava in Africa, and the first application of the KASP technique for insect identification.