Natural enemies associated with some economic pests in Egyptian agro-ecosystems

Abstract No doubt, there are changes in insect pest problems facing the farmers in the newly reclaimed land as well as in the old valley in Egypt due to different reasons, e.g., pesticide misuse and pest resistance, secondary pest outbreaks, absence or inefficient presence of natural enemies, and climate changes. Since the 1990s, the Ministry of Agriculture and Land Reclamation emphasizes to spread the philosophy of integrated pest management (IPM) among the farmers to utilize all suitable means, techniques, and approaches for maintaining pest population levels below those causing economic losses. Among these means is understanding the role of natural enemies in the agro-ecosystem to preserve and encourage their presence and enhance their role in suppressing pest populations as a main factor among the IPM strategies. Thus, it is of essential need to know more about the existing natural enemies associated with the key pests of the economic crops representing different agro-ecosystems in Egypt to develop a successful utilization of biological control agents within the frame of such IPM programs. Thus, it was found necessary to update their recent status as natural resources in various agro-ecosystems. These data are considered a review article eagerly needed for strategies of IPM of serious insect and mite pests in Egypt. The role of the biological control agents, mainly parasitoids and predators in different economic crops, is highlighted

Impact of egg mass layers and scale thicknesses of the fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), on the parasitic performance of Trichogrammatoidea bactrae (Hymenoptera: Trichogrammatidae)

Abstract Background Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is one of the new alien destructive pests of maize and other 350 economic crops. The majority of farmers are still depended upon chemical insecticides to suppress the pest, but S. frugiperda has succeeded to develop resistance against most of the chemical families. Improving an effective environmentally-friendly approach is highly recommended. Therefore, the egg parasitoids are the best weapon for managing the FAW in the early egg stage due to the feeding behavior of their larvae. In this regard, the impact of FAW egg mass layers and scale thicknesses, as physical barriers, on the parasitic performance of the egg-parasitoid species, Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae), in non-choice and choice tests was assessed. Besides, the efficacy of FAW-produced adult wasps on the next generation based on the rates of parasitism, adults' emergence, and female progeny was determined. Results Obtained results exhibited that T. bactrae was able to parasitize all exposed FAW egg masses but with different rates related to the layers’ number and scales' thicknesses in both tests. One-layer (83.18, 78.24%) and two-layer egg masses (65.99, 76.42%) had significantly the highest parasitism rate, while three layers (42.15, 46.05%) was the least one, in both tests, respectively. All parasitoids emerged after 10–12 days with high rates (~ 88–98%) from all the tested egg masses, and the majority offspring were female-biased in both tests. Furthermore, parasitic performance in F1 progeny was similar with that recorded in parental generation in terms of parasitism rate, high parasitoid emergency (~ 87–95%), and strongly female-biased (~ 68–76%) in all the exposed egg masses. Conclusions The egg parasitoid, T. bactrae, could be an efficient and recommended bio-control agent against FAW as its greatest ability to overcome the layers’ number and scales’ thickness

On the control of the cotton aphid, Aphis gossypii Glov. (Hemiptera: Aphididae), on cucumber in greenhouses

Abstract The objective of this study was to apply a biological control program on cucumber crop under greenhouse conditions, using biological control agents compared with insecticides to control the cotton aphid, Aphis gossypii Glover. The treatments were conducted at Dokki, Giza, Egypt, through two cucumber summer plantations in 2015 and 2016. Inspection was made once a week to determine the population density of A. gossypii, one of the major pests on cucumber. Aphid infestation occurred from week 6 to week 12 in 2015 and from week 4 to week 11 in 2016. Adults of the aphid parasitoid Aphidius colemani Viereck and larvae of the predatory coccinellid, Coccinella septempunctata L., were released in the biological greenhouse in weeks 8, 9, and 10 in season 2015 and 7, 8, and 9 in season 2016. In the insecticide greenhouse, the recommended insecticide program was used. The cost of control in the biological control greenhouses was more than that in the insecticide one, but the yield was much higher, recording 63.88% increase in 2015 and 64.91% in 2016

Effect of Protection of Mountainous Vegetation against Over-Grazing and Over-Cutting in South Sinai, Egypt

In this study, we evaluated the species diversity, density, cover, and size index of plant species within and outside 37 enclosures in the South Sinai mountainous region (Egypt), which had been protected for six years (March 2012–March 2018) against over-grazing and over-cutting for medicinal and fuel purposes. Within and outside the enclosures, the plant species were recorded, and their density (individuals per 100 m2) and cover (cm per 100 cm) were estimated using the line-intercept method. The biovolume of each individual of each species was calculated as the average of its height and diameter. The species richness was calculated as the average number of species per enclosure, and the species turnover was calculated as the ratio between the total number of species and the species richness. The relative evenness was calculated using the Shannon–Weaver index, whereas the relative concentration of dominance was calculated using the Simpson index. Detrended correspondence analysis (DCA) was applied to ordinate the vegetation inside and outside the enclosures depending on the species cover. The unpaired t-test was applied to assess the statistically significant differences in the species density, cover, and biovolume inside and outside the enclosures. By the end of the six-year period, the vegetation pattern inside the enclosures became more or less stable, presumably because of the stopping of grazing and cutting, which also led to an increase in the plant diversity, density, and cover. In general, the protection of vegetation in South Sinai improved its diversity, density, and cover. In addition, the topographic and physiographic heterogeneity in this region results in microclimatic variations, which play a major role in governing its natural vegetation

Effect of Protection of Mountainous Vegetation against Over-Grazing and Over-Cutting in South Sinai, Egypt

In this study, we evaluated the species diversity, density, cover, and size index of plant species within and outside 37 enclosures in the South Sinai mountainous region (Egypt), which had been protected for six years (March 2012–March 2018) against over-grazing and over-cutting for medicinal and fuel purposes. Within and outside the enclosures, the plant species were recorded, and their density (individuals per 100 m2) and cover (cm per 100 cm) were estimated using the line-intercept method. The biovolume of each individual of each species was calculated as the average of its height and diameter. The species richness was calculated as the average number of species per enclosure, and the species turnover was calculated as the ratio between the total number of species and the species richness. The relative evenness was calculated using the Shannon–Weaver index, whereas the relative concentration of dominance was calculated using the Simpson index. Detrended correspondence analysis (DCA) was applied to ordinate the vegetation inside and outside the enclosures depending on the species cover. The unpaired t-test was applied to assess the statistically significant differences in the species density, cover, and biovolume inside and outside the enclosures. By the end of the six-year period, the vegetation pattern inside the enclosures became more or less stable, presumably because of the stopping of grazing and cutting, which also led to an increase in the plant diversity, density, and cover. In general, the protection of vegetation in South Sinai improved its diversity, density, and cover. In addition, the topographic and physiographic heterogeneity in this region results in microclimatic variations, which play a major role in governing its natural vegetation

Mechanistic Insights on the In Vitro Antibacterial Activity and In Vivo Hepatoprotective Effects of <i>Salvinia auriculata</i> Aubl against Methotrexate-Induced Liver Injury

Methotrexate (MTX) is widely used in the treatment of numerous malignancies; however, its use is associated with marked hepatotoxicity. Herein, we assessed the possible hepatoprotective effects of Salvinia auriculata methanol extract (SAME) against MTX-induced hepatotoxicity and elucidated the possible fundamental mechanisms that mediated such protective effects for the first time. Forty mice were randomly allocated into five groups (eight/group). Control saline, MTX, and MTX groups were pre-treated with SAME 10, 20, and 30 mg/kg. The results revealed that MTX caused a considerable increase in blood transaminase and lactate dehydrogenase levels, oxidative stress, significant activation of the Nod-like receptor-3 (NLPR3)/caspase-1 inflammasome axis, and its downstream inflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18). MTX also down-regulated nuclear factor erythroid 2-related factor 2 (Nrf2) expression. Additionally, it increased the immunostaining of nuclear factor kappa-B (NF-κB) and downstream inflammatory mediators. Furthermore, the hepatic cellular apoptosis was dramatically up-regulated in the MTX group. On the contrary, prior treatment with SAME significantly improved biochemical, histopathological, immunohistochemical alterations caused by MTX in a dose-dependent manner. The antibacterial activity of SAME has also been investigated against Acinetobacter baumannii clinical isolates. LC-ESI-MS/MS contributed to the authentication of the studied plant and identified 24 active constituents that can be accountable for the SAME-exhibited effects. Thus, our findings reveal new evidence of the hepatoprotective and antibacterial properties of SAME that need further future investigation