In vitro insecticidal effect of commercial fatty acids, ß-sitosterol and rutin against the sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae)

The sugarcane aphid, Melanaphis sacchari Zehntner (Hemiptera: Aphididae), is the main pest of sorghum, Sorghum bicolor L. Moench (Poaceae), in Mexico. To control this insect, farmers currently use synthetic chemical insecticides, which are toxic to humans and biodiversity. However, natural products are a promising potential source of safer alternative means to control different agricultural pests. The main objective of this study was to evaluate the insecticidal effect of contact by fumigation of pure molecules of four commercial fatty acids (palmitic, stearic, pentadecanoic and linoleic acids), the phytosterol ß -sitosterol, and the flavonoid rutin. The results showed that fatty acids were the most effective against M. sacchari ; the highest mortality rate (85%) was produced by linoleic acid and the LC 50 was 1,181 ppm, followed by stearic and palmitic acids with mortality percentages of 74 and 63%, respectively, at a concentration of 2,500 ppm at 72 h. The positive control, imidacloprid, had 100% mortality in 24 h and the tween 20 negative control exhibited 4% mortality in 72 h. Our results show that commercial fatty acids are effective against adults of M. sacchari , and can be considered an environmentally friendly alternative to the frequent use of synthetic chemical insecticides.

Microbiome analyses of 12 psyllid species of the family Psyllidae identified various bacteria including Fukatsuia and Serratia symbiotica, known as secondary symbionts of aphids

Background Psyllids (Hemiptera: Psylloidea) comprise a group of plant sap-sucking insects that includes important agricultural pests. They have close associations not only with plant pathogens, but also with various microbes, including obligate mutualists and facultative symbionts. Recent studies are revealing that interactions among such bacterial populations are important for psyllid biology and host plant pathology. In the present study, to obtain further insight into the ecological and evolutionary behaviors of bacteria in Psylloidea, we analyzed the microbiomes of 12 psyllid species belonging to the family Psyllidae (11 from Psyllinae and one from Macrocorsinae), using high-throughput amplicon sequencing of the 16S rRNA gene. Results The analysis showed that all 12 psyllids have the primary symbiont, Candidatus Carsonella ruddii (Gammaproteobacteria: Oceanospirillales), and at least one secondary symbiont. The majority of the secondary symbionts were gammaproteobacteria, especially those of the family Enterobacteriaceae (order: Enterobacteriales). Among them, symbionts belonging to “endosymbionts3”, which is a genus-level monophyletic group assigned by the SILVA rRNA database, were the most prevalent and were found in 9 of 11 Psyllinae species. Ca. Fukatsuia symbiotica and Serratia symbiotica, which were recognized only as secondary symbionts of aphids, were also identified. In addition to other Enterobacteriaceae bacteria, including Arsenophonus, Sodalis, and “endosymbionts2”, which is another genus-level clade, Pseudomonas (Pseudomonadales: Pseudomonadaceae) and Diplorickettsia (Diplorickettsiales: Diplorickettsiaceae) were identified. Regarding Alphaproteobacteria, the potential plant pathogen Ca. Liberibacter europaeus (Rhizobiales: Rhizobiaceae) was detected for the first time in Anomoneura mori (Psyllinae), a mulberry pest. Wolbachia (Rickettsiales: Anaplasmataceae) and Rickettsia (Rickettsiales: Rickettsiaceae), plausible host reproduction manipulators that are potential tools to control pest insects, were also detected. Conclusions The present study identified various bacterial symbionts including previously unexpected lineages in psyllids, suggesting considerable interspecific transfer of arthropod symbionts. The findings provide deeper insights into the evolution of interactions among insects, bacteria, and plants, which may be exploited to facilitate the control of pest psyllids in the future.

Foraging and nest maintenance activity of the leafcutter ant Acromyrmex lobicornis (Hymenoptera: Formicidae) in an organic vineyard in the Monte desert of Mendoza, Argentina

Exclusive to the Neotropical region, leaf cutter ants are considered agricultural pests, although they can also have a positive effect on plants. In Mendoza vineyards, vegetal biodiversity is minimal, therefore they cut off this plant as a feeding resource. Acromyrmex lobicornis Emery it is mostly nocturnal and forages according to temperature. Foraging and maintenance activity was measured monthly in 14 colonies, throughout a full day at fourhour intervals, from October 2019 to March 2020. Acromyrmex lobicornis showed different seasonal patterns of foraging activity. Foraging intensity was highest throughout January and February, intermediate during December, and lowest in October and November. A bimodal feeding pattern was observed, foraging both day and night avoiding the hottest hours. The maximum collection of fragments was observed in the range of 10 and 19 °C, less between 20 - 39 °C, minimum between 40 - 49 °C and null between 0 - 9 °C. The nest - maintenance activity was maximum between 20 - 29 °C, less between 30 - 39 ° C, minimum between 40 - 49 °C and null between 0 - 20 °C.

Application of Allelopathy in Crop Production

Need for food production has been increasing greatly in recent years throughout the world. The interest on the supply of quality of food has also increased, but a significant loss of crop production was observed annually, especially the main cereal crops, including rice, wheat and maize, due to the presence of weeds accompanying them in the growing season. Allelopathy has emerged as an alternative approach to solve problem agriculture that including: crop rotations, intercropping, crop residue incorporation and aqueous extracts all that used to explore allelopathy for pest management, enhancement of growth and crop production. As will allelopathic consider as weeds, insect and diseases natural control. Secondary metabolites biosynthesis of at high rates have a great role in provides defense against abiotic stresses. In plant rhizosphere allelochemicals exuded improve nutrient acquisition through the processes of solublization; biological nitrification; chelation and selected retention. In this chapter, application of the allelopathic phenomenon in crop production is discussed and his roller in managing agricultural pests and improving the productivity of agricultural systems. It was found that allelochemicals promote plant growth and production at low concentration; however it can suppress the growth if applied at high concentrations, for that can be used allelopathic compounds for weed control by used high concentrations of plant residues or aqueous extracts of plant.

Identification and Characterization Analysis of Transient Receptor Potential Mucolipin Protein of Laodelphax striatellus Fallén

Transient receptor potential mucolipin (TRPML) protein in flies plays a pivotal role in Ca2+ ions release, resulting in membrane trafficking, autophagy and ion homeostasis. However, to date, the characterization of TRPML in agricultural pests remains unknown. Here, we firstly reported the TRPML of a destructive pest of gramineous crops, Laodelphax striatellus. The L. striatellus TRPML (Ls-TRPML) has a 1818 bp open reading frame, encoding 605 amino acid. TRPML in agricultural pests is evolutionarily conserved, and the expression of Ls-TRPML is predominately higher in the ovary than in other organs of L. striatellus at the transcript and protein level. The Bac–Bac system showed that Ls-TRPML localized in the plasma membrane, nuclear membrane and nucleus and co-localized with lysosome in Spodoptera frugiperda cells. The immunofluorescence microscopy analysis showed that Ls-TRPML localized in the cytoplasm and around the nuclei of the intestine cells or ovary follicular cells of L. striatellus. The results from the lipid-binding assay revealed that Ls-TRPML strongly bound to phosphatidylinositol-3,5-bisphosphate, as compared with other phosphoinositides. Overall, our results helped is identify and characterize the TRPML protein of L. striatellus, shedding light on the function of TRPML in multiple cellular processes in agricultural pests.

Source Regions of the First Immigration of Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae) Invading Australia

Fall armyworm is recognized as one of most highly destructive global agricultural pests. In January 2020, it had first invaded Australia, posing a significant risk to its biosecurity, food security, and agricultural productivity. In this study, the migration paths and wind systems for the case of fall armyworm invading Australia were analyzed using a three-dimensional trajectory simulation approach, combined with its flight behavior and NCEP meteorological reanalysis data. The analysis showed that fall armyworm in Torres Strait most likely came from surrounding islands of central Indonesia on two occasions via wind migration. Specifically, fall armyworm moths detected on Saibai and Erub Islands might have arrived from southern Sulawesi Island, Indonesia, between January 15 and 16. The fall armyworm in Bamaga most likely arrived from the islands around Arafura Sea and Sulawesi Island of Indonesia, between January 26 and 27. The high risk period for the invasion of fall armyworm is only likely to have occurred in January–February due to monsoon winds, which were conducive to flight across the Timor Sea towards Australia. This case study is the first to confirm the immigration paths and timing of fall armyworm from Indonesia to Australia via its surrounding islands.

Chitosan in modern agriculture production

In the perspective of return to nature, using scientific and technical progress for improved living standards, people began to search for solutions to alleviate environmental pollution. Researchers intend to make clean, affordable products that are gentle yet effective. Chitosan derived from the exoskeleton of crustaceans, cuticles of insects, cell walls of fungi, and some algae are renowned for many decades to exhibit biotic properties, especially anti-microbial characteristics. Here we review each ingredient for sourcing organic chitosan, with clean raw materials that can make pure, rich, and powerful products working naturally. Our study elaborates advances and utilisation of chitosan for industrial control-release fertilisers by physical, chemical, and multifaceted formulations such as water-retaining super absorbent, polyacrylic acid, and resins. Plant growth-promoting properties of chitosan as a growth regulator, pest/disease resistance, signalling regulation, effect on nuclear deformation, and apoptosis. Chitosan can improve the plant defence mechanism by stimulating photochemistry and enzymes related to photosynthesis. Furthermore, electrophysiological modification induced by chitosan can practically enable it to be utilised as a herbicide. Chitosan has an excellent role in improving soil fertility and plant growth as well as plant growth promoters. It is concluded, chitosan can play a key role in modern agriculture production and could be a valuable source promoting agricultural ecosystem sustainability. Future suggestions will be based on current achievements and also notable gaps. In addition, chitosan has a huge contribution to reducing fertilisers pollution, managing agricultural pests and pathogens in modern-day agriculture.

Genomic signatures and insights into host niche adaptation of the entomopathogenic fungus Metarhizium humberi

The genus Metarhizium is composed of species used in biological control programes of agricultural pests worldwide. This genus includes common fungal pathogen of many insects and mites and endophytes that can increase plant growth. Metarhizium humberi was recently described as a new species. This species is highly virulent against some insect pests and promotes growth in sugarcane, strawberry, and soybean crops. In the present study, we sequenced the genome of M. humberi, isolate ESALQ1638, and performed a functional analysis to determine its genomic signatures and highlight the genes and biological processes associated with its lifestyle. The genome annotation predicted 10633 genes in M. humberi, of which 92.0% are assigned putative functions, and ∼17% of the genome was annotated as repetitive sequences. We found that 18.5% of the M. humberi genome is similar to experimentally validated proteins associated with pathogen-host interaction. Compared to the genomes of eight Metarhizium species, the M. humberi ESALQ1638 genome revealed some unique traits that stood out, e.g.,, more genes functionally annotated as polyketide synthases (PKs), overrepresended GO-terms associated to transport of ions, organic and amino acid, a higher percentage of repetitive elements, and higher levels of RIP-induced point mutations. The M. humberi genome will serve as a resource for promoting studies on genome structure and evolution that can contribute to research on biological control and plant biostimulation. Thus, the genomic data supported the broad host range of this species within the generalist PARB clade and suggested that M. humberi ESALQ1638 might be particularly good at producing secondary metabolites and might be more efficient in transporting amino acids an organics compounds.

Integrated Management of the Cattle Tick Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) and the Acaricide Resistance Mitigation

Resistance to insecticides is one of the major obstacles to the control of agricultural pests, as well as species important to human and veterinary health. The World Health Organization has called insecticide resistance “the great little obstacle against vector-borne diseases”. Rhipicephalus (Boophilus) microplus is one of the most important vector, transmitting diseases to cattle such as anaplasmosis and babesiosis. These diseases cause great economic losses that significantly increased because of the appearance of tick populations resistant to acaricides, as a result of the intensive use of pesticides. Resistance to ixodicides in Latin America is a growing problem, since control of disease-transmitting ticks, depends heavily on the use of pesticides. In Mexico, the resistance of R. microplus to organophosphate compounds, pyrethroids, and recently amidines, has been detected in some areas, affected by multiple acaricide resistance to the three families of ixodicides. The cattle tick R. microplus in addition to the great ecological impact represents the most expensive pest for livestock in Mexico, since the producers are directly affected by this tick, due to the decrease in the production of meat, milk and damage to the skin, as well as the indirect damage, such as the transmission of diseases, including Anaplasmosis and Babesiosis, which, in turn, represents a serious limitation for the introduction of specialized cattle in endemic areas. Therefore, the use of integrated management programs is a mandatory issue that should be implemented in all those areas affected by this parasite.

Predation capacity and larval development of Ceraeochrysa claveri (Neuroptera: Chrysopidae) fed with Raoiella indica (Acari: Tenuipalpidae)

Ceraeochrysa claveri Navás (Neuroptera: Chrysopidae) is a predator found in several agricultural ecosystems and feeds on insects and phytophagous mites. Its high reproductive potential and forage capacity makes it a candidate for biological control of agricultural pests. Raoiella indica Hirst (Acari: Tenuipalpidae) is an important pest that can damage several species of palms, in particular, Cocos nucifera L. Given the scarcity of available knowledge about the biological aspects of Chrysopidae fed with phytophagous mites, the present work aimed to study the larval development of C. claveri fed mainly with R. indica, in order to obtain information that would be of help in the integrated management of this pest. The evaluation was performed in the F0 generation. Larva 3 is the instar that consumes the most mites (F value = 32.99; P > 0.0001) (L3: 46.80 ± 10.12 a; L2: 9.80 ± 1.23 b; L1: 9.40 ± 1.58 b). C. claveri did not complete larval development when fed only with R. indica. Larval instars L1, L2 and L3 lived 7.4 ± 2.2, 7.6 ± 1.9 and 9.0 ± 3.9 days, respectively. The larvae that reached the pupal stage failed to grow further. When adding Sitotroga cerealella Olivier (Lepidoptera: Gelechidae) eggs to the diet, the development lasted 7.9 ± 0.2, 7.4 ± 0.8, 6.5 ± 0.9 and 13.6 ± 0.9 days for L1, L2, L3 and pupae, respectively. The adults lived on average 6.7 ± 4.9 days. The sexual ratio was rt = 0.42. According to the conditions under which the experiment was carried out, it can be inferred is that C. claveri cannot complete its development by feeding only on R. indica, and that it thus consumes this mite as an occasional prey. Highlights: Ceraeochrysa claveri is a predator found in various agricultural ecosystems and feeds on insects and phytophagous mites. Raoiella indica is an important mite that can damage several species of palms, in particular Cocos nucifera Ceraeochrysa claveri does not complete its biological cycle by feeding only on indica. By adding another protein source to L3, it can reach the adult stage in 35.4±2.8 days. Ceraeochrysa claveri does not complete its cycle by feeding only on R. indica and consequently takes this mite as occasional prey.