Haemonchus contortus affect small ruminants all over the world. Anthelmintics cause resistance, contamination, and a risk of public health. Prosopis laevigata is a plant used as a home remedy against many diseases in Mexico. This study arose from a preliminary study where a P. laevigata hydroalcoholic extract (Pl-hae) showed anthelmintic activity (aa) against H. contortus. Searching for bioactive compounds (bac) with high aa, the Pl-hae was fractioned obtaining an aqueous (Aq-F) and an ethyl acetate fraction (EtAc-F), and a flavonoid with aa identified as isorhamnetin was obtained from EtAc-F. Both fractions were in vitro assessed by the egg hatch test (eht) and larval mortality (lm) assays. The bac obtained from EtAc-F were characterised by NMR analysis. The highest aa were recorded with EtAc-F, resulting in 100% eht and 80.45% lm at 0.75 and 30 mg/mL, respectively. Alterations in eggs and larvae attributed to isorhamnetin were recorded by environmental scanning electron microscopy, confocal laser scanning and by high-resolution digital-coupled camera. This flavonoid caused 100% eht at 0.07 mg/mL after 48 h and 100% lm at 7.5 mg/mL after 72 h exposure. Isorhamnetin has promising potential as an anthelmintic against sheep haemonchosis.

Pithecellobium dulce (Robx.) Benth is an arboreal legume used in traditional medicine for the treatment of several ailments, including a number of intestinal disorders, and as a natural deworming. The objective of this study was to evaluate the ovicidal activity of a hydroalcoholic extract (HA-E) and its fractions (aqueous, Aq-F and organic, EtOAc-F) from P. dulce leaves, as well as subfractions (C1F1–C17) obtained from EtOAc-F against Haemonchus contortus eggs. The HA-E, Aq-F, and EtOAc-F were assessed at 0.03–5.00 mg/mL and subfractions (C1F1–C17) were assessed at 0.06–1.00 mg/mL. The HA-E and Aq-F showed an ovicidal activity close to 100% at 2.5 mg/mL, and EtOAc-F displayed the highest anthelmintic effect (100% at 0.25 mg/mL). Meanwhile, the sub-fractions with the highest ovicidal effect were C1F6, C1F9, C1F10, C1F11, and CIF13. The main compounds identified in the most active fractions (C1F9, C1F11, and C1F13) were kaempferol (1), quercetin (2), coumaric acid (3), ferulic acid (4), luteolin 7-O-rhamnoside (5), quercetin 3-O-rhamnoside (6), and a caffeoyl derivate (NI). The results indicate that P. dulce leaves exhibit a potent anthelmintic activity and contain bioactive compounds able to inhibit egg hatching in H. contortus. Therefore, this plant could be used for the control of gastrointestinal nematodes in small ruminants.

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.

The nematocidal activity of an Oxalis tetraphylla hydroalcoholic extract against the nematode Haemonchus contortus (Hc) was assessed in vitro and the major compounds associated with nematocidal activity were identified. One hydroalcoholic extract was obtained from O. tetraphylla stems and leaves (Ot HE-SLE). The in vitro lethal concentrations (LC50 and LC90) against both eggs and exsheathed Hc infective larvae (L3) were assessed. Ot HE-SLE showed a potent ovicidal activity (LC50 = 0.213 mg/mL; LC90 = 0.71 mg/mL) and larvicidal effect (LC50 = 28.01 mg/mL; LC90 = 69.3 mg/mL). Later on, the extract was bipartitioned to obtain an ethyl acetate phase (EtOAc-Ph) and an aqueous phase (Aq-Ph). Both phases were assessed against Hc eggs at 0.25 and 1.0 mg/mL concentrations. The results with EtOAc-Ph showed 93.6% ovicidal activity, while 96.6% was recorded with Aq-Ph at 48 h post-confrontation (PC). In the case of larvicidal activity, both phases were assessed at 28 mg/mL; Aq-Ph showed >80% larvicidal activity 24 and 72 h PC, while EtOAc-Ph did not show important activity. HPLC analysis showed the presence of coumaric acid and flavonols. Flavonol compounds were the major compounds and were associated with the nematocidal activity. Additionally, the Aq-Ph that showed the highest activity was purified, and the fraction F3 showed the highest nematocidal activity.

This is the first record of the fungus Flavocillium subprimulinum in Mexico. The isolate was taxonomically characterised and cultured in potato dextrose broth (PDB), Czapek–Dox broth (CzDoxB), and sweet potato dextrose broth (SPDB) to obtain its filtrates (FLCF). The nematocidal activity (NA) of three FLCF concentrations was assessed against Haemonchus contortus L3. Protease activity (PA) was assessed with SDS-PAGE, followed by a zymogram. The NA of the FLCF reached 94.43% in PDB and 95.82% in CzDoxB, respectively, at 100 mg/mL. Lower mortality (64%) was found in SPDB at 100 mg/mL. SDS-PAGE showed bands (in PBS) of ~25, ~40, and ~55 kDa. The zymogram showed protein bands (PBs) with PA in the media, including PBs of ~14, ~40, and ~55 kDa. This study establishes the basis for exploring the potential use of this fungus against H. contortus, which is considered the most pathogenic parasite affecting lambs.