Effects of the maternal social environment on the mating signals and mate preferences of adult offspring in Enchenopa treehoppers.

Much is known about how the maternal environment can shape offspring traits via intergenerational effects. It is less clear, however, whether such effects may reach adult offspring sexual traits, with potential consequences for sexual selection and speciation. Here, we report effects of adult female aggregation density on the mating signals and mate preferences of their offspring in an insect that communicates via plant-borne vibrational signals. We experimentally manipulated the density of aggregations experienced by egg-laying mothers, reared the offspring in standard densities, and tested for corresponding differences in their signals and preferences. We detected a strong effect in male signals, with sons of mothers that experienced low aggregation density signalling more. We also detected a weak effect on female mate preferences, with daughters of mothers that experienced low aggregation density being less selective. These adjustments may help males and females find mates and secure matings in low densities, if the conditions they encounter correspond to those their mothers experienced. Our results thus extend theory regarding adjustments to the social environment to the scale of intergenerational effects, with maternal social environments influencing the expression of the sexual traits of adult offspring.

Plant viruses exploit insect salivary GAPDH to modulate plant defenses.

Salivary proteins of insect herbivores can suppress plant defenses, but the roles of many remain elusive. One such protein is glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from the saliva of the Recilia dorsalis (RdGAPDH) leafhopper, which is known to transmit rice gall dwarf virus (RGDV). Here we show that RdGAPDH was loaded into exosomes and released from salivary glands into the rice phloem through an exosomal pathway as R. dorsalis fed. In infected salivary glands of R. dorsalis, the virus upregulated the accumulation and subsequent release of exosomal RdGAPDH into the phloem. Once released, RdGAPDH consumed H2O2 in rice plants owing to its -SH groups reacting with H2O2. This reduction in H2O2 of rice plant facilitated R. dorsalis feeding and consequently promoted RGDV transmission. However, overoxidation of RdGAPDH could cause potential irreversible cytotoxicity to rice plants. In response, rice launched emergency defense by utilizing glutathione to S-glutathionylate the oxidization products of RdGAPDH. This process counteracts the potential cellular damage from RdGAPDH overoxidation, helping plant to maintain a normal phenotype. Additionally, salivary GAPDHs from other hemipterans vectors similarly suppressed H2O2 burst in plants. We propose a strategy by which plant viruses exploit insect salivary proteins to modulate plant defenses, thus enabling sustainable insect feeding and facilitating viral transmission.

Nanoscale mesh acts as anti-adhesive surface against particulate contamination in eyes of whiteflies.

In many insects the surface of the eye is nanostructured by arrays of protuberances termed ommatidial gratings which provide the cuticle with anti-reflective, anti-wetting and self-cleaning properties. The hypothesised anti-contamination role of the gratings against dust and pollen results from theoretical predictions on grating geometry and experiments on synthetic replicas of ommatidia surfaces but has not yet been proven in an animal. Whiteflies are biological test beds for anti-contamination surfaces because they deliberately distribute wax particles extruded from abdominal plates over their entire bodies. The numerous particles protect the animal against water evaporation and radiation, but may severely impair vision. Using scanning electron microscopy (SEM) and CryoSEM, we here show that the cornea of whiteflies exhibits ~ 220 nm wide mesh-like structures forming hexagonal gratings with thin ~ 40 nm connecting walls. Quantitative measurements of wax particles on the eye show that the nanostructures reduce particle contamination by more than ~ 96% compared to other areas of the cuticle. Altogether, our study is the first description of a predicted optimized grating geometry for anti-contamination in an arthropod. The findings serve as evidence of the high effectiveness of nanostructured surfaces for reducing contact area and thus adhesion forces between biological surfaces and contaminating particles.

Insect ribosome-rescuer Pelo-Hbs1 complex on sperm surface mediates paternal arbovirus transmission.

Arboviruses can be paternally transmitted by male insects to offspring for long-term persistence, but the mechanism remains largely unknown. Here, we use a model system of a destructive rice reovirus and its leafhopper vector to find that insect ribosome-rescuer Pelo-Hbs1 complex expressed on the sperm surface mediates paternal arbovirus transmission. This occurs through targeting virus-containing tubules constituted by viral nonstructural protein Pns11 to sperm surface via Pns11-Pelo interaction. Tubule assembly is dependent on Hsp70 activity, while Pelo-Hbs1 complex inhibits tubule assembly via suppressing Hsp70 activity. However, virus-activated ubiquitin ligase E3 mediates Pelo ubiquitinated degradation, synergistically causing Hbs1 degradation. Importantly, Pns11 effectively competes with Pelo for binding to E3, thus antagonizing E3-mediated Pelo-Hbs1 degradation. These processes cause a slight reduction of Pelo-Hbs1 complex in infected testes, promoting effective tubule assembly. Our findings provide insight into how insect sperm-specific Pelo-Hbs1 complex is modulated to promote paternal virus transmission without disrupting sperm function.

Influence of weather conditions and plant growth on populations of the solenopsis mealybug (Phenacoccus solenopsis Tinsley) infesting maize plants.

The cotton or solenopsis mealybug, Phenacoccus solenopsis (Tinsley, 1898) (Hemiptera: Pseudococcidae), infests various host plants in Egypt. A study was conducted to observe the incidence of mealybugs and the possible influences of meteorological variables and plant age on the insect population of maize (single-hybrid 168 yellow maize cultivar) plants in Esna district, Luxor governorate, Egypt, in two consecutive seasons (2021 and 2022). P. solenopsis infested maize plants from the 3rd week of June to harvest, and had three peaks of seasonal incidence/season namely; in the 1st week of June in the 3rd/4th week of July, and the 2nd week of August. Similarly, there were three peaks in the percent of infestations per season. In the first season, the average population density of P. solenopsis per sample was 174.04 ± 16.93 individuals, and in the second season, 156.72 ± 14.28 individuals. The most favorable climate for P. solenopsis population increase and infestation occurred in August in the first season and in September in the second season, while June was less suitable in both growing seasons (as estimated by weekly surveys). The combined effects of weather conditions and plant age are significantly related to the estimates of P. solenopsis populations, with an explained variance (E.V.) of 93.18 and 93.86%, respectively, in the two seasons. In addition, their influences explained differences in infestation percentages of 93.30 and 95.54%, respectively, in the two seasons. Maize plant age was the most effective factor in determining changes in P. solenopsis population densities in each season. The mean daily minimum temperature in the first season and mean daily dew point in the second season were the most important factors affecting the percent changes in infestation. However, in both seasons, the mean daily maximum temperature was the least effective variable in population and infestation variation. This study paves the way for monitoring and early detection of mealybugs in maize; as well as the optimal climatic conditions for its development.

Identification and expression profiles of olfactory-related genes in the antennal transcriptome of Graphosoma rubrolineatum (Hemiptera: Pentatomidae).

Graphosoma rubrolineatum (Hemiptera: Pentatomidae) is an important pest of vegetables and herbs (e.g., Umbelliferae and Cruciferae) in China, Siberia, Korea, and Japan. Insects are highly dependent on their olfactory system to detect odorants. However, no molecular-mediated olfactory genes in G. rubrolineatum have yet been identified. In this study, we first established the antennal transcriptome of G. rubrolineatum and identified 189 candidate olfactory genes, including 31 odorant-binding proteins (OBPs), 15 chemosensory proteins (CSPs), four sensory neuron membrane proteins (SNMPs),94 odorant receptors (ORs), 23 ionotropic receptors (IRs), and 22 gustatory receptors (GRs). Additionally, phylogenetic trees were constructed for olfactory genes between G. rubrolineatum and other hemipteran insects. We also detected the expression profiles of ten OBPs, five CSPs, two SNMPs, five ORs, four IRs, and four GRs by real-time quantitative PCR. The results revealed that most genes (GrubOBP1/11/31, GrubCSP3/8, GrubSNMP1a/1b, GrubOrco/OR9/11/13, GrubGR1/4/22, GrubIR25/75h/76b/GluR1) were highly expressed in the antennae, GrubOBP13/31 and GrubCSP4/11/12 were highly expressed in the legs, while GrubOBP20 and GrubGR19 were highly expressed in the wings. Our results will enrich the gene inventory of G. rubrolineatum and provide further insight into the molecular chemosensory mechanisms of G. rubrolineatum.

'Candidatus Liberibacter brunswickensis' colonization has no effect to the early development of Solanum melongena.

This study is the first to investigate the presence and movement of the novel Liberibacter species 'Candidatus Liberibacter brunswickensis' (CLbr) in eggplant, Solanum melongena. The psyllid, Acizzia solanicola can transmit CLbr to eggplant and CLbr can be acquired by CLbr-negative A. solanicola individuals from CLbr-positive eggplants. In planta, CLbr can replicate, move and persist. Investigation into the early development of eggplants showed that CLbr titres had increased at the inoculation site at 14 days post inoculation access period (DPIAP). CLbr had become systemic in the majority of plants tested by 28 DPIAP. The highest bacterial titres were recorded at 35 DPIAP in all samples of the inoculated leaf, the roots, stems and the midrib and petiole samples of the newest leaf (the top leaf). This finding strongly suggests that CLbr movement in planta follows the source to sink relationship as previously described for 'Ca. Liberibacter asiaticus' (CLas) and 'Ca. Liberibacter solanacearum' (CLso). No symptoms consistent with Liberibacter-associated diseases were noted for plants colonised by CLbr during this study, consistent with the hypothesis that CLbr does not cause disease of eggplant during the early stages of host colonisation. In addition, no significant differences in biomass were found between eggplant colonised with CLbr, compared to those that were exposed to CLbr-negative A. solanicola, and to control plants.

Essential roles of histone lysine methyltransferases EZH2 and EHMT1 in male embryo development of Phenacoccus solenopsis.

Paternal genome elimination (PGE) is an intriguing but poorly understood reproductive strategy in which females are typically diploid, but males lose paternal genomes. Paternal genome heterochromatin (PGH) occurs in arthropods with germline PGE, such as the mealybug, coffee borer beetles, and booklice. Here, we present evidence that PGH initially occurs during early embryo development at around 15 h post-mating (hpm) in the cotton mealybug, Phenacoccus solenopsis Tinsley. Transcriptome analysis followed by qPCR validation indicated that six histone lysine methyltransferase (KMT) genes are predominantly expressed in adult females. We knocked down these five genes through dsRNA microinjection. We found that downregulation of two KMT genes, PsEZH2-X1 and PsEHMT1, resulted in a decrease of heterochromatin-related methylations, including H3K27me1, H3K27me3, and H3K9me3 in the ovaries, fewer PGH male embryos, and reduced male offspring. For further confirmation, we obtained two strains of transgenic tobacco highly expressing dsRNA targeting PsEZH2-X1 and PsEHMT1, respectively. Similarly, fewer PGH embryos and fewer male offspring were observed when feeding on these transgenic tobacco plants. Overall, we present evidence that PsEZH2-X1 and PsEHMT1 have essential roles in male embryo survival by regulating PGH formation in cotton mealybugs.

Chromosome-level genome assembly of the invasive pest Pseudococcus jackbeardsleyi (Hemiptera: Pseudococcidae).

Among over 2,000 species of mealybugs (Hemiptera: Pseudococcidae), only 13 genomes have been published so far, seriously limiting the researches on the phylogeny and adaptive evolution of this group. The continuous publication of mealybug genomes will significantly facilitate our exploration of the biological characteristics, detrimental attributes, and control strategies of the Pseudococcidae family. Jack Beardsley mealybug (Pseudococcus jackbeardsleyi) as one of the hazardous invasive pests, it could cause enormous losses to the fruit and vegetable industries worldwide. Herein, we combined Nanopore long-read, short-read Illumina and Hi-C sequencing, generating a high-quality chromosome-level genome assembly of P. jackbeardsleyi. The genome size was determined to be 334.818 Mb, which was assembled into 5 linkage groups with a N50 of 67.233 Mb. The BUSCO analysis demonstrated the completeness of the genome assembly and annotation are 95.7% and 92.8%, respectively. The developed high-quality genome will serve as an asset for delving into the genetic mechanisms underlying the invasiveness of P. jackbeardsleyi, thereby offering a crucial theoretical foundation for the prevention and management of Pseudococcidae pests.

Modeling human activity-related spread of the spotted lanternfly (Lycorma delicatula) in the US.

The spotted lanternfly (Lycorma delicatula) has recently spread from its native range to several other countries and forecasts predict that it may become a global invasive pest. In particular, since its confirmed presence in the United States in 2014 it has established itself as a major invasive pest in the Mid-Atlantic region where it is damaging both naturally occurring and commercially important farmed plants. Quarantine zones have been introduced to contain the infestation, but the spread to new areas continues. At present the pathways and drivers of spread are not well-understood. In particular, several human activity related factors have been proposed to contribute to the spread; however, which features of the current spread can be attributed to these factors remains unclear. Here we collect county level data on infestation status and four specific human activity related factors and use statistical methods to determine whether there is evidence for an association between the factors and infestation. Then we construct a network model based on the factors found to be associated with infestation and use it to simulate local spread. We find that the model reproduces key features of the spread 2014 to 2021. In particular, the growth of the main infestation region and the opening of spread corridors in the westward and southwestern directions is consistent with data and the model accurately forecasts the correct infestation status at the county level in 2021 with 81% accuracy. We then use the model to forecast the spread up to 2025 in a larger region. Given that this model is based on a few human activity related factors that can be targeted, it may prove useful to incorporate it into more elaborate predictive forecasting models and in informing management efforts focused on interstate highway transport and garden centers in the US and potentially for current and future invasions elsewhere globally.

Temporal resource continuity for egg parasitoids of Dalbulus maidis (Hemiptera: Cicadellidae) during winter on irrigated maize crops and edge grasses.

Little is known about winter-season parasitism of eggs of the corn leafhopper Dalbulus maidis DeLong (Hemiptera: Cicadellidae), an important pest of maize throughout the Americas. Our study, conducted in Mexico, aimed to characterize winter-season parasitism of corn leafhopper eggs on maize crops cultivated with drip irrigation and on wild grasses that grow on the edges of maize crops when maize is not present. Maize leaves baited with D. maidis eggs were used to trap the egg parasitoids in the field. In the first year (2022), parasitism of D. maidis eggs was investigated in maize fields planted contiguously on different dates (asynchronous planting). In the second year (2023), parasitism of D. maidis eggs was evaluated in edge grasses and in adjacent maize crops planted on the same date (synchronous). The highest percentage of parasitism (53%), percentage of emergence, and total abundance of egg parasitoids were found in asynchronous maize fields. Here, Anagrus virlai Triapitsyn (Hymenoptera: Mymaridae), Paracentrobia subflava (Girault) (Hymenoptera: Trichogrammatidae), and Pseudoligosita sp. (Hymenoptera: Trichogrammatidae) wasps were found parasitizing the D. maidis eggs, with P. subflava being the most abundant. In wild edge grasses, only P. subflava was found, showing low levels of parasitism, while in synchronous maize, P. subflava increased its percentage of parasitism (up to 37%), percentage of emergence, and abundance, during winter. These results suggest that P. subflava acts as an efficient biological control agent of D. maidis in irrigation-grown maize crops during the winter season, and that edge grasses are overwinter habitats for P. subflava.

Tomato yellow leaf curl virus manipulates Bemisia tabaci, MEAM1 both directly and indirectly through changes in visual and volatile cues.

The sweetpotato whitefly, Bemisia tabaci MEAM1, is one of the most devastating pests of row-crop vegetables worldwide, damaging crops directly through feeding and indirectly through the transmission of many different viruses, including the geminivirus Tomato yellow leaf curl virus (TYLCV). Y-tube olfactometer tests were conducted at different stages of TYLCV infection in tomatoes to understand how TYLCV affects B. tabaci behavior. We also recorded changes in tomato hosts' color and volatile profiles using color spectrophotometry and gas chromatography-mass spectrometry (GC-MS). We found that the infection status of B. tabaci and the infection stage of TYLCV influenced host selection, with uninfected whiteflies showing a preference for TYLCV-infected hosts, especially during the late stages of infection. Viruliferous B. tabaci attraction to visual targets significantly differed from non-viruliferous B. tabaci. Late-stage infected hosts had larger surface areas reflecting yellow-green wavelengths and higher emissions of methyl salicylate in their volatile profiles. These findings shed new light on several critical mechanisms involved in the viral manipulation of an insect vector and its economically important host.

Genetic diversity analysis of Saccharosydne procerus in Hunan region, China.

BACKGROUND: Saccharosydne procerus serves as a significant alternative host for parasitoids of the important rice pest, rice planthoppers. Rearing S. procerus on the water bamboo plants near rice field can provide a parasitic site for parasitic wasps during the idle period of rice fields, thereby stabilizing the number of parasitoids and suppressing the number of rice planthoppers in the field. However, limited understanding of genetic diversity of S. procerus restricts its application. Therefore, this study aims to analyze the genetic diversity of S. procerus in Hunan region. METHODS: In this study, 16 geographical populations of the S. procerus from the Hunan region were used. After screening, ISSR primers were employed for polymorphism detection. POPGENE32 software was used for genetic diversity analysis, and UPGMA clustering was applied for statistical analysis of different geographical populations to generate an evolutionary tree. RESULTS: Eleven ISSR primers were screened, resulting in the detection of 194 amplification locus, of which 126 were polymorphic. The average percentage of polymorphic locus was 64.95%. The mean Nei's gene diversity (H) was 0.2475, the mean Shannon's Information index (I) was 0.3708, and the Genetic diversity index among populations (Gst) was 0.3800. Cluster analysis identified three groups, with most populations concentrated in the second group, indicating no clear genetic structure. This suggests that the 16 populations of S. procerus exhibit high levels of genetic diversity.

Elucidation of ejaculatory bulb proteins in Bemisia tabaci Asia-1 and Asia II-1 and confirmation of their mating transfer via RNAi.

BACKGROUND: Bemisia tabaci, a significant agricultural pest in Asia, contains distinct genetic groups, Asia-1 and Asia II-1. Understanding its reproductive biology, particularly the role of ejaculatory bulb proteins (EBPs) in mating, is crucial. However, EBPs in B. tabaci were not well characterised until this study. METHODS AND RESULTS: The EBPs have been characterised in the Asia-1 and Asia II-1 genetic groups of the whitefly B. tabaci, prevalent in Asia. The transcriptomic analysis yielded over 40,000,000 and 30,000,000 annotated transcripts, respectively, from Asia II-1 and Asia-1. Differential gene expression revealed the presence of 270 upregulated and 198 downregulated genes, with significant differences between these two genetic groups. Orphan genes (1992 numbers) were identified in both genetic groups. We report, for the first time, full-length sequences of EBP genes from B. tabaci. The 10 EBPs each deduced in B. tabaci Asia-1 and Asia II-1 are structurally akin to chemosensory proteins having four conserved cysteine residues. Additionally, we did domain analysis, protein structure prediction, mapping of these EBPs in the chromosomes of B. tabaci, and phylogenetic analysis to track their evolutionary lineage. We have specifically demonstrated the transfer of EBPs from males to females during mating using qPCR and further validated the transfer of EBPs through RNAi. Specifically, we targeted the highly expressed EBPs (EBP-3, 7, and 8 in BtAsia1; EBP-8, 9, and 10 in BtAsia II-1) through feeding bioassays of dsRNAs. Tracking by qPCR revealed that the females, when mated with dsRNA-treated males, did not show expression of the specific EBP, suggesting that the silencing of these genes in males hinders the transfer of EBP to females during mating. CONCLUSION: Our findings provide novel insights into the genomic contours of EBPs in B. tabaci and underscore the potential of RNAi-based strategies for pest management by disrupting the reproductive processes.

Beet curly top virus affects vector biology: the first transcriptome analysis of the beet leafhopper.

Curly top disease, caused by beet curly top virus (BCTV), is among the most serious viral diseases affecting sugar beets in western USA. The virus is exclusively transmitted by the beet leafhopper (BLH, Circulifer tenellus) in a circulative and non-propagative manner. Despite the growing knowledge on virus-vector interactions, our understanding of the molecular interactions between BCTV and BLH is hampered by limited information regarding the virus impact on the vector and the lack of genomic and transcriptomic resources for BLH. This study unveils the significant impact of BCTV on both the performance and transcriptome response of BLHs. Viruliferous BLHs had higher fecundity than non-viruliferous counterparts, which was evident by upregulation of differentially expressed transcripts (DETs) associated with development, viability and fertility of germline and embryos in viruliferous insects. Conversely, most DETs associated with muscle movement and locomotor activities were downregulated in viruliferous insects, implying potential behavioural modifications by BCTV. Additionally, a great proportion of DETs related to innate immunity and detoxification were upregulated in viruliferous insects. Viral infection also induced notable alterations in primary metabolisms, including energy metabolism, namely glucosidases, lipid digestion and transport, and protein degradation, along with other cellular functions, particularly in chromatin remodelling and DNA repair. This study represents the first comprehensive transcriptome analysis for BLH. The presented findings provide new insights into the multifaceted effects of viral infection on various biological processes in BLH, offering a foundation for future investigations into the complex virus-vector relationship and potential management strategies for curly top disease.

Baseline of susceptibility, risk assessment, biochemical mechanism, and fitness cost of resistance to dimpropyridaz, a novel pyridazine pyrazolecarboxamide insecticide, in Bemisia tabaci from China.

Bemisia tabaci is one of the most destructive agricultural insect pests around the world, and it has developed high levels of resistance to most pesticides. Dimpropyridaz, a novel insecticide developed by BASF, displays excellent activity against piercing-sucking insect pests. In this study, baseline of susceptibility showed all tested field populations of B. tabaci are susceptible to dimpropyridaz. After continuous selection with dimpropyridaz in the lab, a B. tabaci strain (F12) developed 2.2-fold higher level of resistance compared with a susceptible MED-S strain, and the realized heritability (h2) was estimated as 0.0518. The F12 strain displayed little cross-resistance to afidopyropen, cyantraniliprole, sulfoxaflor, or abamectin, and significantly increased activity of cytochrome P450 monooxygenase (P450). The fitness cost of dimpropyridaz resistance was evident in F12 strain, which had a relative fitness of 0.95 and significantly lower fecundity per female compared with MED-S strain. Taken together, B. tabaci displays high susceptibility to dimpropyridaz in the field, and low risk of developing resistance to dimpropyridaz under successive selection pressure. Little cross-resistance to popular insecticides was found, and fitness cost associated dimpropyridaz resistance was observed. Higher activity of cytochrome P450 in the F12 strain, may be involved in the process of detoxifying dimpropyridaz in whitefly.

Differential expression of "Candidatus Liberibacter solanacearum" genes and prophage loci in different life stages of potato psyllid.

Psyllid species, including the potato psyllid (PoP) Bactericera cockerelli (Sulc) (Triozidae) serve as host and vector of "Candidatus Liberibacter spp." ("Ca. Liberibacter"), which also infects diverse plant hosts, including citrus and tomato. Psyllid transmission of "Ca. Liberibacter" is circulative and propagative. The time of "Ca. Liberibacter" acquisition and therefore vector life stage most competent for bacterial transmission varies by pathosystems. Here, the potato psyllid-"Ca. Liberibacter solanacearum" (CLso) pathosystem was investigated to dissect CLso-prophage interactions in the tomato plant and PoP-psyllid host by real-time quantitative reverse transcriptase amplification of CLso genes/loci with predicted involvement in host infection and psyllid-CLso transmission. Genes/loci analyzed were associated with (1) CLso-adhesion, -invasion, -pathogenicity, and -motility, (2) prophage-adhesion and pathogenicity, and (3) CLso-lysogenic cycle. Relative gene expression was quantified by qRT-PCR amplification from total RNA isolated from CLso-infected 1st-2nd and 4th-5th nymphs and teneral adults and CLso-infected tomato plants in which CLso infection is thought to occur without SC1-SC2 replication. Gene/loci expression was host-dependent and varied with the psyllid developmental stage. Loci previously associated with repressor-anti-repressor regulation in the "Ca Liberibacter asiaticus"-prophage pathosystem, which maintains the lysogenic cycle in Asian citrus psyllid Diaphorina citri, were expressed in CLso-infected psyllids but not in CLso-infected tomato plants.

Investigating the second whitefly population outbreak within a decade in the cotton growing zone of North India.

The whitefly, Bemisia tabaci (Gennadius), is a polyphagous and major pest of cotton worldwide. Both adults and nymphs of B. tabaci affect the crop by causing direct and indirect damage. A severe whitefly outbreak was experienced during 2015 on cotton in North India and this was followed by a profound infestation during 2022. The present research rigorously examined whether the proliferation in the whitefly population was an outbreak or the result of a multi factor resurgence. During 2015, whitefly counts remained above the economic threshold level (ETL) between 28th and 35th Standard Meteorological Week (SMW). However, during 2022 above ETL population was observed in 27th SMW and it persisted until 36th SMW. The peak incidence of the whitefly was noticed during 31st and 29th SMW in 2015 and 2022, respectively. The early pest build up in 2022 and longer persistence (≥10 weeks) over the cotton season resulted in more damage to cotton crop. Additionally, pest survillence across the zone on the farmers' fields during 2022 revealed 44.4 per cent spots (585 out of 1,317 locations) above ETL while the corresponding locations in 2015 was 57% (620 out of 1,089). Thus, in 2022 infestation was not uniform in the entire zone wherein only few blocks of Punjab, Haryana and Rajasthan states of India experienced severe infestations of the whitefly. This study reports the complex of factors including weather, delayed sowing, use of tank mixtures/ subleathal doses of insecticides, pest resurgence etc. that might have possibly contributed to these upsurges in whitefly on cotton in north India.

Exploring Phylogenetic Relationships of the Mecocephala Group (Hemiptera: Pentatomidae) Using Continuous and Discrete Characters, with Notes on Taxonomy.

The Mecocephala group comprises about 50 species, restricted to the Neotropics and with the highest species richness in Neotropical South America. Several species use rice as host plants and their identification is facilitated by the presence of exaggerated head proportions and a unique male genitalic morphology. The taxonomy of the group has been extensively explored, but inferring its monophyly and especially its internal phylogenetic relationships has been challenging. Here, we inferred the phylogenetic relationships for the group assembling the most complete taxonomic sampling to date, analyzing discrete and continuous morphological characters through equal and implied weighted parsimony analyses. The monophyly of the group was recovered, but internal relationships varied slightly according to the dataset tested. Thus, we propose internal arrangements for the group and provide a formal description of the Mecocephala group, diagnoses for each genus, a dichotomous key to identify its genera, and illustrations of the morphological characters and type species.

Improved control of Trialeurodes vaporariorum using mixture combinations of entomopathogenic fungi and the chemical insecticide spiromesifen.

Greenhouse whitefly (Trialeurodes vaporariorum) is a major global pest, causing direct damage to plants and transmitting viral plant diseases. Management of T. vaporariorum is problematic because of widespread pesticide resistance, and many greenhouse growers rely on biological control agents to regulate T. vaporariorum populations. However, these are often slow and vary in efficacy, leading to subsequent application of chemical insecticides when pest populations exceed threshold levels. Combining chemical and biological pesticides has great potential but can result in different outcomes, from positive to negative interactions. In this study, we evaluated co-applications of the entomopathogenic fungi (EPF) Beauveria bassiana and Cordyceps farinosa and the chemical insecticide spiromesifen in laboratory bioassays. Complex interactions between the EPFs and insecticide were described using an ecotoxicological mixtures model, the MixTox analysis. Depending on the EPF and chemical concentrations applied, mixtures resulted in additivity, synergism, or antagonism in terms of total whitefly mortality. Combinations of B. bassiana and spiromesifen, compared to single treatments, increased the rate of kill by 5 days. Results indicate the potential for combined applications of EPF and spiromesifen as an effective integrated pest management strategy and demonstrate the applicability of the MixTox model to describe complex mixture interactions.