The European honey bee, Apis mellifera L., is the bee species with the largest geographic distribution in the world. It is considered a pollinator generalist of wild plants and agricultural crops, as well as honey bee products as honey, beeswax, and propolis. For this reason, it plays an extremely important role in the world’s ecosystems, economy, and food security. However, Apis mellifera is facing population declines due to biotic and abiotic factors, such as climate change, habitat loss, agrochemical use, and emerging pests and diseases. Pests and diseases are directly associated with a phenomenon known as colony collapse disorder (CCD), which is linked with the loss of millions of bee colonies annually worldwide. One particularly important pest is the varroa mite, which is already widely distributed and is considered the major threat to apiculture. In this review, we compile documentation of the presence and distribution of pests and diseases reported to affect Apis mellifera in Mexico. Surveys demonstrate that the following pests are present: Varroa destructor, Acarapis woodi, Aethina tumida, Galleria mellonella, as well as the diseases caused by Melissococcus plutonius, Paenibacillus larvae, Vairimorpha (Nosema) apis, V. ceranae, Ascosphaera apis and several viruses. It should be noted that the distribution and presence of European bee pathogens throughout the beekeeping states of Mexico is not very well defined, due to the lack of current bee health studies in apiaries or nationwide databases to quickly update information on their distribution and incidence.

The mining activity has left mine tailings with high quantities of heavy metals and metalloids. Due their extreme toxicity, they represent a hostile environment for microbial colonization; however, there are metalotolerant bacteria in these mining wastes, and this is attributed to mechanisms of bioaccumulation and biotransformation of metals. The native bacteria from El Fraile mine tailings have developed adaptation mechanisms that allow them to persist in a toxic environment, thus, the objective of this study was to isolate and identify bacteria with the ability to tolerate, bioaccumulate or biotransform heavy metals. Our study was based on descriptive observations, we isolated 141 strains from water, leachate, soil, and rhizosphere and stems of plants from El Fraile mine tailings, Guerrero, Mexico. Bacterial tolerance was determined by the minimum inhibitory concentration in different metallic salts, the capacity of bioaccumulation of Ag, Pb, Cr, and Cd, and by the biotransformation of As (III) and Cr6+; in addition, representative bacteria were identified using 16S rRNA gene sequences. The results of the 141 strains analyzed showed ascending tolerance to Cd2+ 2 mM, Cu2+ 5 mM, Pb2+ 9 mM, Zn2+ 9 mM, Ag2+ 10 mM, As3+ 30 mM, and As5+ 45 mM. Only 9.24 and 39% of the strains bioaccumulated Zn2+, Pb2+ and Ag2+. In regard to biotransformation, 9% oxidized As3+ to As5+, and 7 and 24% reduced As5+ to As3+ and Cr6+ to Cr3+, respectively. The genera that prevailed were Chryseobacterium sp., Staphyloccoccus sp., Stenotrophomonas sp., Acinetobacter sp., Bacillus sp., Serratia sp., and Enterobacter sp. These results showed that in El Fraile mine tailings, there are bacterial strains capable of bioaccumulating and biotransforming heavy metals and metalloids; therefore, further studies must be conducted to know their potential in the processes of bioremediation of areas polluted with metals.

Aphids (Hemiptera: Aphididae) are cosmopolitan generalist pests of many agricultural crops. Their ability to reproduce rapidly through parthenogenesis allows them to quickly reach population sizes that are difficult to control. Their damage potential is further exacerbated when they act as vectors for plant pathogens, causing diseases in plants. Aphids are typically managed through the widespread use of insecticides, increasing the likelihood of short-term insecticide resistance. However, for the past few decades, entomopathogenic bacteria have been used as an alternative management strategy. Entomopathogenic bacteria have demonstrated their effectiveness for biologically suppressing insect pests, including aphids. In addition to identifying bacterial species that are pathogenic to aphids, research has been conducted on toxins such as Cry, Cyt, Vip, recombinant proteins, and other secondary metabolites with insecticidal activity. Most studies on aphids have been conducted in vitro, exposing them to an artificial diet contaminated with entomopathogenic bacteria or bacterial metabolites for periods ranging from 24 to 96 h. The discovery of new bacterial species with insecticidal potential, as well as the possibility of biotechnological applications through the genetic improvement of crops, will provide more alternatives for managing these agricultural pests in the future. This will also help address challenges related to field application.

Melanaphis sorghi is a pest that is native to Africa but is now distributed worldwide. In 2013, its destructive capacity was demonstrated when it devastated sorghum crops in the United States and Mexico, making it a new pest of economic importance in North America. At the time, the phytosanitary authorities of both countries recommended the use of pesticides to control the outbreak, and biological control products for the management of this pest were not known. In response to the outbreak of M. sorghi in North America, several field studies have been performed in the last decade on sorghum crops in the USA and Mexico. Works have focused on assessing resistant sorghum hybrids, pesticide use, and recruitment of associated aphid predators and entomopathogens for natural control of M. sorghi populations. The objective of this review is to compile the information that has been generated in the past decade about indigenous enemies affecting M. sorghi naturally in the field, as well as the search for biological control alternatives and evaluations of interactive effects of resistant sorghum hybrids, pesticides, and natural enemies. To date, different predators, parasitoids, fungi, and bacteria have been evaluated and in many cases found to affect M. sorghi populations in sorghum agroecosystems or laboratory bioassays, and the use of resistant sorghum varieties and pesticides did not have clear toxic effects on natural enemy populations. Many of the macroorganisms and microorganisms that have been evaluated as potential biological controls have shown potential as alternatives to synthetic pesticides for keeping M. sorghi population densities below economic damage thresholds and are compatible with integrated management of sorghum aphids. While most tests of these biological alternatives have shown that they have aphidicidal potential against sorghum aphids, it is crucial to take into account that their effectiveness in the field depends on a number of abiotic and biotic factors, including soil texture, temperature, humidity, and natural enemies.

Aphids (Hemiptera: Aphididae) are cosmopolitan generalist pests of many agricultural crops. Their ability to reproduce rapidly through parthenogenesis allows them to quickly reach population sizes that are difficult to control. Their damage potential is further exacerbated when they act as vectors for plant pathogens, causing diseases in plants. Aphids are typically managed through the widespread use of insecticides, increasing the likelihood of short-term insecticide resistance. However, for the past few decades entomopathogenic bacteria have been used as an alternative management strategy. Entomopathogenic bacteria have demonstrated their effectiveness for biologically suppressing insect pests, including aphids. In addition to identifying bacterial species that are pathogenic to aphids, research has been conducted on toxins such as Cry, Cyt, Vip, recombinant proteins, and other secondary metabolites with insecticidal activity. The discovery of new bacterial species with insecticidal potential, or the possibility of biotechnological applications through genetic improvement of crops, will provide more alternatives for managing these agricultural pests in the future.

Nomamyrmex esenbeckii, commonly known as the legionary ant, belongs to the group of army ants. This social insect employs a cooperative hunting method that is considered more evolved than solitary hunting ants. Their main preys are other ants and termites. However, in this article, we report for the first time in Mexico the predatory behavior of N. esenbeckii on Apis mellifera colonies.