Essential oils are very popular among organic growers because they are ecologically safe, do not have mammalian toxicity, and cannot be resistant to a variety of contaminants. Four essential oils, Lemon, Lavender, Peppermint, and Neem, were tested for larvicide efficacy against the dengue fever vector Aedes aegypti larvae under laboratory conditions using dipping bioassay techniques. Among the essential oils tested, lemon, peppermint, and lavender oils showed high larvicidal activity against larvae of Ae. aegypti. Lemon oil showed the highest effects (LC₅₀ 10.676 ppm), while Peppermint, Lavender and Neem oil showed the lowest effects (LC₅₀ 21.380, 29.818 and 38.058 ppm, respectively). As a result, the mixture of lemon oil (LC₅₀) with Peppermint oil (LC₂₅) showed the highest co-toxicity factor, whereas the mixture of Lemon oil (LC₅₀) with Diesel oil (LC₂₅) showed the lowest co-toxicity factor. Based on the results of this study, it appears that essential oils may be useful as larvicides against Ae. aegypti larvae. In search of new natural larvicides, these compounds may provide an alternative to Synthetic insecticides as these are environmentally safe insecticides.

The potential range and distribution of insects are greatly impacted by climate change. This study evaluates the potential global shifts in the range of Gryllus bimaculatus (Orthoptera: Gryllidae) under several climate change scenarios. The Global Biodiversity Information Facility provided the location data for G. bimaculatus, which included nineteen bioclimatic layers (bio01–bio19), elevation data from the WorldClim database, and land cover data. For the near future (2021–2040) and far future (2081–2100) under low (SSP1-2.6) and high (SSP5-8.5) emission scenarios, the Beijing Climate Center Climate System Model (BCC-CSM2-MR) and the Institute Pierre-Simon Laplace Coupled Model Intercomparison Project (IPSL-CM6A-LR) were used. Assessing habitat gain, loss, and stability for G. bimaculatus under potential scenarios was part of the evaluation analysis. The results showed that the main environmental parameters affecting the distribution of G. bimaculatus were mean temperature of the driest quarter, mean diurnal temperature range, isothermality, and seasonal precipitation. Since birds, small mammals, and other insectivorous insects rely on G. bimaculatus and other cricket species as their primary food supply, habitat loss necessitates management attention to the effects on the food web. The spread of G. bimaculatus as a sentinel species in the food chain and its use in animal feeds are both impacted by habitat loss and gain.

A laboratory strain of Aedes aegypti (L) was subjected repeatedly to larval selection pressure with two bacterial insecticides, spinosad (Saccharopolyspora spinosa) and bacilod (Bacillus thuringiensis israelensis). The results indicated that the mosquito Ae. aegypti acquired low resistance to spinosad and bacilod by about 3.1 and 2.4-fold, respectively, due to selection pressure for fifteen successive generations. The slope values of the selected strains were increased gradually from one generation to the next, indicating moderate homogeneity between individuals in their response to the test bio-insecticide. Moreover, larval selection with current bacterial bioinsecticides prolonged the time required to digest a blood meal. It showed an evident decrease in the reproductive potential of adult mosquitoes surviving selected larvae.

Seeds susceptibility of eight broad bean varieties to Callosobruchus maculatus (F.) and Callosobruchus chinensis (L.) infestation were studied for the first time in free- and no-choice methods in the laboratory of Plant Protection Department, Faculty of Agriculture, Zagazig University. The relation between certain seed physical characteristics and some biological and and infestation parameters of both insects in the two studied methods were evaluated. None of these varieties were resistant to both insects, showing various levels of susceptibility. Biological and infestation parameters were significantly different among varieties except the developmental period. In free- choice method, Giza 3 was the most susceptible variety to both insects, since produced the highest progeny of 246.67 and 75.67 adults and susceptibility index (SI) of 10.25 and 7.42, respectively, while the least susceptible variety was Giza 716. In no– choice method, Nubaria 5 and Sakha 1 were the most susceptible varieties to C. chinensis, while Nubaria 3 and Giza 3 to C. maculatus. Differences between physical characters of varieties were significant. Seed hardness were correlated negatively and seed coat thickness positively with laid eggs, progeny and (SI) of both insects in free-choice method. Also seed coat thickness correlated positively with weight loss and seed damage (%) of C. chinensis and negatively of C. maculatus. To reduce seed losses the cultivation of the least susceptible variety (Giza 716) is encouraged and considered for breeding purposes to avoid insecticide usage.

Mango fruits are one of the strategic fruit crops in different countries that are attacked by several serious pests such as Cryptoblabes gnidiella and Scirtothrips mangiferae. Natural extracts, especially essential oils, provide several promising insecticide agents to control different insects as an alternative to synthetic insecticides. Using Clevenger-type hydrodistillation, the essential oils of five thyme plants—Thymus vulgaris, Origanum vulgare, Thymus argenteus, Thymus citriodorus, and Origanum syriacum—from Saudi Arabia and Egypt were extracted, and GC/MS analysis was performed. In addition, some chemical parameters of the five species were determined, such as chlorophyll a, chlorophyll b, β-carotene, total antioxidant capacity, total phenols, and total flavonoids. Two compounds, thymol and carvacrol, were identified in T. vulgaris and O. vulgare at ratios of 69.45 and 64.82%, respectively. These major compounds were isolated and identified using ¹H NMR analysis. The insecticidal potentials of the five essential oils and their pure isolated compounds were evaluated on C. gnidiella and S. mangiferae on mango inflorescences. The results showed that T. vulgaris and O. vulgare oils were the most potent against C. gnidiella (LC₅₀, 183.33 and 164.68 ppm, respectively) and S. mangiferae (18.93 and 16.93 ppm, respectively). Thymol and carvacrol had the highest effect on both insects. Furthermore, the effect of thymol and carvacrol at LC₅₀ values on some biochemical parameters of C. gnidiella was determined. Therefore, thymol and carvacrol from Thymus species are promising compounds that could be used as insecticides against the harmful insects C. gnidiella and S. mangiferae on mango inflorescences.