Distribution Of Phenacoccus Solenopsis Infesting Okra Plants: Evidence for Improving a Pest Scouting Method.

Understanding insect behavior is a prerequisite for establishing pest scouting tools for determining possible damage and implementing control measures for the cotton mealybug, Phenacoccus solenopsis (Hemiptera: Pseudococcidae) on okra plants. Field trials were conducted to estimate the distribution modalities of P. solenopsis on plants in different cardinal directions, plant strata, leaf surfaces, and field depth (spaces from field boundaries), in a private okra field (Balady cultivar) at Esna district, Luxor Governorate during two consecutive seasons (2021 and 2022). Results revealed that P. solenopsis attacked okra plants, were observed from the first week of March through the end of July during each season, and occurred on all okra field directions in all plant levels and on leaf surfaces, on all the dates of weekly inspections. During the two seasons, there were highly significant differences in population, as well as infestation percentages in various cardinal directions, and very significant changes between the various stratums of plant and on leaf surfaces, as well as between the various distances from field boarders. P. solenopsis favors the lower leaf surface of the top stratum of the plant, in the south and east aspects, where its population was constantly abundant throughout the season, and pests more highly attacked okra plants distant from the farm borders than close plants over each season. The current information can be used to help design mealybug monitoring and control programs on okra plants

Toxicity assessment of certain insecticides on the red soft scale insect, Pulvinaria tenuivalvata (Newstead) infesting sugarcane plants

Pulvinaria tenuivalvata (Newstead) (Hemiptera: Coccidae) red soft scale insect is one of the most prevalent insect pests that attacks sugarcane plants. Insecticidal efficiency of six selected insecticides (Malatox, Sulfar, Admiral, Nomolt, Tafaban and Biover) was evaluated for their impact against nymphs and adult females of P. tenuivalvata on sugarcane leaves using leave dipping methods. This investigation was carried out for two successive seasons (July 2021-2022) at the laboratory of the Plant Protection Research Department at the El-Mattana Agricultural Research Station, Luxor Governorate, Egypt. Obtained results showed that the tested insecticides varied in efficacy on the different stages of pest (nymphs and adult females). Moreover, the nymphal stage of P.tenuivalvata was more susceptible to the tested pesticides compared to the adult stage. Admiral and nomolt were the most toxic against the nymphal and adult female stages of P. tenuivalvata on sugarcane leaves, sulfar, however, was the least successful in controlling this pest

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Relationship between the population density of the white mango scale insect, Aulacaspis tubercularis (Newstead) (Hemiptera: Diaspididae) and the yield loss of mango trees in Luxor Governorate, Egypt

The main objective of this work is to estimate the relationship between the pest population, Aulacaspis tubercularis (Newstead), infestation through pest activity peaks in September, November, April and June on the yield loss of Goleck mango trees at the district of Esna, Luxor Governorate through two seasons (2016/2017 and 2017/2018). The results revealed that the  increment of population density and incidence infestation by the pest gradually decreased the yield of mango, consequently  increased the percentage of the yield loss when the data of the yield were colligated with the pest population peaks and its infestation incidence in September, November, April and June months through 2016/2017 and 2017/2018 seasons.Increasing one individual  of pest per leaf caused a reduction of the mango yield by 2.14, 1.56, 2.05 and 4.28 kg/tree and 2.08, 1.42, 2.46 and 1.31 kg/tree through the peaks of the two seasons, respectively. Subsequently, increased the yield loss percentages by 1.52, 1.12, 1.47 and 3.06% and 1.44, 0.98, 1.70 and 0.90% when the yield data were correlated with the population density of the pest in September, November, April and June peaks during the two connective seasons (2016/2017 and 2017/2018), respectively. These results confirmed that the pest population and the percentages of infestation incidence of A. tubercularis during the peak of April caused the least expected values in the yield of mango and the greatest loss in mango yield. On contrary, the peak during November was less effective, causing the highest expected values in mango yield and the lowest reduction in the yield of mango during the seasons of 2016/2017 and 2017/2018. Generally, the reduction in the yield of mango was a summation of different factors (time, level and variety ability to infestation)

The impact of maize irrigation intervals and potassium fertiliser rates on mealybug populations, vegetative growth, and resulting yield

The mealybug, Phenacoccus solenopsis (Hemiptera: Coccomorpha: Pseudococcidae), is one of the main pests attacking maize plants in Egypt. Field trials were carried out in the maize field to assess the influence of irrigation periods and potassium fertiliser rates on the mealybug (P. solenopsis) population estimates, vegetative growth, resulting yield, and its components for the maize cultivar (‘Single-Hybrid 168 Yellow’) in the Luxor Governorate, Egypt. Results revealed that unfertilised plants irrigated every seven days had higher pest population densities than other treatments over the two seasons. The fertilised treatments at 114 kg K2O∙ha -1 that received water every 10 days had the smallest population of P. solenopsis in every season. Data during the two seasons (2021 and 2022) revealed that the maize to which potassium fertiliser was added by 114 kg K2O∙ha -1 and irrigated every 10 days had vegetative growth (plant height, diameter, and number of green leaves per plant), yield and its components (average ear length, ear weight, number of grains per ear, weight of 1000 grains, and grain yield) significantly increased as compared to those of the plants that were irrigated every 7 days and without adding fertiliser. A higher dose of potassium fertiliser reduces the infestation of P. solenopsis but causes an increment of maize vegetative growth. This affects the final yield. This information aids farmers in comprehending the good agronomic techniques of maize plants to decrease the infestation of mealybugs and increase the yield