Semiochemicals are defined as informative molecules mainly used in plant-insect or insect-insect interactions as alternative or complementary components to insecticide approaches in different integrated pest management strategies. They are used to manipulate insect behaviour by affecting the survival and/or reproduction of insect pests for controlling their infestations on crops. The present review provides a basic summary of the utilization of semiochemicals for controlling insect pests. Two main topics were explored in this study. The first topic focuses on a description of semiochemicals and their types (pheromones and allelochemicals). Pheromones represent an intraspecific communication amidst members of the same species. Allelochemicals, produced by individuals of one species, modify the behavior of individuals of a different species (i.e. an interspecific effect). Allelochemicals include different informative molecules such as: allomones, kairomones, synomones, antimones and apneumones. The second topic focuses on the application of semiochemicals in IPM programs. Different semiochemicals are included in integrated pest management programs in various ways such as monitoring, mass trapping, attract-and-kill, push-pull, and disruption strategies. Pheromones are promising and can be used singly or in integration with other control strategies for monitoring and controlling insect pests in agricultural systems. For example, sex pheromones have been applied in mass trapping, disruption and attract-and-kill tactics in IPM programs.

During potato desiccation the above-ground parts can be destroyed by mechanical, mechanical-chemical, or chemical methods. In the current study, the mechanical-chemical method was used and instead of chemical compounds natural nonanoic acid (pelargonic acid) was used. Nonanoic acid is a natural active ingredient that can be extracted from vegetable oil (rapeseed oil). It is a short chain fatty acid and a natural product, that fits well with the principles of the Green Revolution, which has introduced restrictions worldwide on the use of chemical plant protection products and promotes natural ones. For comparison carfentrazone-ethyl and glufosinate-ammonium were used. Studies were carried out in Poland during 2012–2014 with the potato variety Ikar, which is known to be among the varieties difficult to desicccate in Poland. The results show that potato leaves were efficiently destroyed by both nonanoic acid and chemicals (carfentrazone-ethyl and glufosinate-ammonium). The level of destruction varied from 94.5% to 99%. The level of stalk drying caused by nonanoic acid was high and it was similar to that of chemical desiccants. None of the studied desiccants significantly affected yield, vascular necrosis or quantity of starch in tubers.

Currently more and more research is being done on integrated weed management to reduce or avoid herbicide use. Some growers are already using isotherapic dilutions to control weeds in organic farming. Isotherapy is different from homeopathy because it uses diluted and potentized (succussed) solutions of alcoholic macerate of the very pest causing health troubles. We set up a germination experiment to test if isotherapic dilutions of leaf macerate of annual ryegrass affect the dynamics of its seed germination in Petri dishes. Our results were diverse, from no effect to 10% more growing degree days necessary to reach 50% germination. It is doubtful that so low an effect will contribute to integrated weed management unless the slightly delayed germination triggers secondary effects at other life stages. This is in accordance with the scientific literature on that topic: two-fifths of the reports showed no effect, two-fifths resulted in positive responses and one-fifth had diverse responses for the criteria tested.

The granary weevil, Sitophilus granarius (L.), is one of the most important internal feeders of stored grain. Nanotechnology has become one of the most promising new approaches for pest control in recent years. In our screening program, laboratory trials were conducted to determine the effectiveness of silica nanoparticles (SNPs) and zinc nanoparticles (ZNPs) against the larval stage and adults of S. granarius on stored wheat. Nanoparticles of silica and zinc were synthesized through a solvothermal method. They were then used to prepare insecticidal solutions of different concentrations and tested on S. granarius. Silica nanoparticles (SNPs) were found to be highly effective against S. granarius causing 100% mortality after 2 weeks. ZNPs were moderately effective against this pest.

Plant responses to glyphosate applied at different doses were examined for one glyphosate resistant (R) and one glyphosate susceptible (S) population of Conyza albida and C. bonarienis. Growth rates and development stages of five R C. albida and three R C. bonarienis populations were also compared with those of their respective S counterparts to investigate the possible impact of the glyphosate resistance trait on their fitness. The GR50 values for C. albida R (3.94−5.22 kg a.i. · ha−1) and S (0.24−0.31 kg a.i. · ha−1) populations were higher than those of C. bonariensis R (0.60−1.51 kg a.i. · ha−1) and S (0.10−0.13 kg a.i. · ha−1). The growth rate (slope b) of one R C. albida population was lower than the respective S and other R populations, while growth rates of most R and S C. bonariensis populations were similar. Some R populations showed inconsistent differences in some development stages when compared to those of the S ones, which cannot be attributed to the glyphosate resistance trait.

Potato leaf blight disease caused by Ulocladium atrum (Syn. Stemphylium atrum) is an important and epidemic disease in potato-growing regions of Iran. In this study, 30 isolates of the disease were collected from the main potato-growing regions of Iran and were analyzed on the basis of morphological characterization and pathogenicity. Based on morphological characteristics, all isolates were identified as U. atrum. Pathogenicity studies indicated that all 30 isolates were pathogenic on potato “Agria” to varying degrees. Five U. atrum isolates causing potato leaf blight disease, obtained from the Plant Pathology Laboratory, Isfahan Research Center for Agriculture and Natural Resources, Isfahan, Iran, were also examined in this study. A total of 35 isolates were genetically analyzed using random amplified polymorphic DNA (RAPD) and inter-simple sequence repeats (ISSR) markers. Cluster analysis using the un-weighted pair group method with the arithmetic average (UPGMA) method for RAPD marker revealed no clear grouping of the isolates obtained from different geographical regions. The groupings, based on morphological characteristics, virulence variability and RAPD analysis, were not correlated. Cluster analysis using Jaccard’s coefficient for ISSR divided the U. atrum isolates into four main groups, in which there was no significant correlation between the isolate groupings regarding their geographic location and pathogenicity. Using molecular techniques genetic variability was detected among the accessions, with cophenetic correlation coefficients (CCC) of 0.80 for RAPDs and 0.89 for ISSRs. The RAPD and ISSR marker results corresponded well, with a correlation of 0.55.

The cotton mealybug, Phenacoccus solenopsis (Tinsley) (Hemiptera: Pseudococcidae), has become a widespread pest causing serious losses in several economically important crops, particularly cotton. To the best of our knowledge this is the first record of cotton mealybug, P. solenopsis as a new pest of potato plants in Egypt. The insect was noticed on potato plants for the first time during the growing season of 2016 (mid-August 2016). Mealybug specimens were collected from infested potato plants and identified as P. solenopsis. In an attempt to control this insect pest species, seven insecticides viz. sulfoxaflor, abamectin + thiamethoxam, spirotetramat, thiamethoxam, imidacloprid, buprofezin, and pymetrozine, belonging to different chemical groups, were tested for their effect against nymphs and adult females of P. solenopsis on potato under field conditions. The obtained results indicated that sulfoxaflor, abamectin + thiamethoxam and spirotetramat had the highest efficacy against P. solenopsis recording 80.3–96.05% reduction of the insect population after 21 days of application. Thiamethoxam, imidacloprid, buprofezin and pymetrozine failed to exhibit sufficient P. solenopsis control.

The excessive use of pesticides is a problem in most parts of the world today because of their broad and unspecific target range that is considerably harmful. The accumulation of several chemical insecticide residues based on chlorpyrifos-methyl, organochlorine, different isomers of HCH, DDT etc., in Triticum aestivum L. plants can be dangerous. Hence, there is an urgent need to develop potential and safer alternative measures. Wheat (Triticum aestivum L.) is a major cereal crop grown and used for food, animal feed, beverages and furniture accessories in most parts of the world. It also serves as a host to various insect pests. Our previous studies showed the insecticidal potency and specificity of short ssDNA oligonucleotides from the inhibitor of apoptosis (IAP-2 and IAP-3) genes of Lymantria dispar multicapsid nuclear polyhedrosis virus (LdMNPV) against gypsy moth (L. dispar) larvae, a possible insect pest of non-host plants like wheat. Consequently, the present study analyzes the effects of ssDNA oligonucleotides used as DNA insecticides on wheat (T. aestivum) plant biomass, plant organs and some biochemical parameters as a marker of the safety margin on non-target organisms. The results obtained on plant biomass showed that groups treated with ssDNA oligonucleotides at concentrations of 0.01 pmol · μl−1, 0.1 pmol · μl−1 and 1 pmol · μl−1 varied in comparison with the control group, but remained harmless to plant growth and development, while the treatment concentration of 0.001 pmol · μl−1 did not affect the plant biomass. The glucose, protein and phosphorous biochemical parameters, analyzed after 21 days, showed that the ssDNA oligonucleotides used were equally safe. The data obtained for the plant organs (leaves and root lengths) indicate that the phenomenon of DNA insecticides can be further studied and developed for plant protection while improving the growth of plant organs even for a non-target organism such as wheat T. aestivum plants.

Seed-borne diseases of wheat such as Fusarium head blight (FHB), a fungal disease caused by several species of Fusarium, results in reduced yield and seed quality. The aim of this study was to identify the Fusarium species, the effect of Fusarium-infected seeds on germination and vigor indices and to determine the location of Fusarium spp. in seeds, as well as to investigate the pathogenicity and variability of aggressiveness of the isolates obtained from pre-basic seeds wheat fields in Iran. According to morphological and molecular characters, the species F. graminearum, F. culmorum, F. avenaceum and F. poae were identified. Among the isolates, F. graminearum was the predominant species with the highest frequency and relative density of 92.9% and 70.9%, respectively. We observed that germination and vigor indices were decreased due to increased Fusarium-infected seeds. Results indicated significant differences among cultivars and seed-borne Fusarium levels. While a higher infection level of Fusarium spp. most commonly occurred in the seed coat, only F. graminearum was observed in embryos. Our study about pathogenicity showed that 77.3% of the Fusarium spp. isolates were not pathogenic and 22.7% isolates of Fusarium spp. were pathogenic or weakly pathogenic. Our results indicated that variability in aggressiveness among isolates of a species and positive correlation may be determined by pathogenicity tests. This is the first time the location of Fusarium spp. in seeds has been identified. It is also the first time that Fusarium-infected seeds in pre-basic seeds wheat fields of Iran have been evaluated.

Rice blast is the main disease of rice plants in Indonesia and several countries worldwide. Controlling this disease using chemical fungicides has harmful effects on the environment. Therefore, we need biocontrol agents which are more environmentally friendly such as rice phyllosphere bacteria. This study aimed to explore bacteria producing bioactive compounds from the rice phyllosphere environment to control blast disease. A total of 88 isolates were successfully isolated from rice leaves in Sukabumi, Situgede, and Jasinga (West Java, Indonesia). From them, we obtained 22 bacteria isolates with antifungal activity against Pyricularia oryzae in vitro assay. In addition, seven non-pathogenic bacteria were obtained from further screening in hypersensitivity, hemolysis and pathogenicity assays, namely STGG 3, STGG 7, STGG 8, STGG 14, SKBV 1, STGV 8, and SKBG 78. To show their antifungal activity, we tested crude extracts of these seven isolates and the results revealed that all the crude extracts can inhibit the growth of P. oryzae. Based on a genetic approach, isolates STGG 3, STGG 7, and STGG 14 were found to have both nonribosomal peptide synthetases (NRPS) and polyketide synthases (PKS) genes, while isolate SKBV 1 only had the NRPS gene. The NRPS and PKS genes from potential isolates were similar to NRPS and PKS genes of Bacillus sp. in different strains. Furthermore, molecular identification based on the 16S rRNA gene revealed that the seven potential isolates belong to three genera, i.e. Bacillus (STGG 3, STGG 7, STGG 8, STGG 14, SKBV 1), Enterobacter (STGV 8) and Brachybacterium (SKBG 78). We suggest that the seven isolates found in this study have potency and could be recommended as biocontrol agents of blast disease caused by P. oryzae.

Ecology and life characteristics of overwintering larvae of the European corn borer (Ostrinia nubilalis Hbn.) (Lep.: Crambidea) are partly unexplored due to their hidden lifestyle. In plant protection research the best way to study these phenomena is to apply less used, non-destructive, in vivo methods. The objective of our CT survey was to examine the factors influencing the location of the overwintering O. nubilalis larvae in maize stalks. The findings obtained by CT-analysis can be used for monitoring the presence and location of O. nubilalis larvae in the stalk, as well as both their displacement and movement. Our results showed that both the location and the distance from the brace root of O. nubilalis larvae were significantly influenced by the sampling time, the number of larvae per plant, the stalk diameter and finally the prevailing temperature. The location of the larvae situated nearest to the brace roots (first larvae) was significantly lower in stalks containing several larvae, than those where only a single larva was found in the stalk. The thickness of stalks was related to the simultaneous presence of more larvae, and to the ground level position of the first larvae. These overwintering larvae were located closer to the brace root (and to the soil), possibly because of having moved downwards inside the stalk, where the temperature is slightly milder than in the upper part of the stalk.

The adverse effects of synthetic acaricides on humans, animals, non-target organisms and the ecosystem are serious problems. Thus, there is a new trend to use nanotechnology for developing new, natural, bio and safe acaricides for mite control in green-pest management. This is the first work for preparing a nanoformulation of rosemary essential oil (EO) and evaluating its effect against the two-spotted spider mite Tetranychus urticae Koch. GC/MS analysis of rosemary EO showed that 1,8 cineole (31.45%), borneol (11.07%), α-pinene (10.91%), D-limonene (9.19%), L-linalool (8.86%), D-camphor (7.32%), γ-terpinene (3.92%), linalyl acetate (3.37%), α-terpineol (3.32%), and p-cymene (1.82%) were the major components. After 6 min of sonication, a nanoemulsion of rosemary EO was formulated with a droplet size of 139.9 nm. The balance between oil (lyophilic) and surfactant (hydrophilic) was correlated with the droplet size and the stability of the nanoemulsion. Spray application of rosemary nanoemulsion showed high acaricidal activity against immature and adult two-spotted spider mites T. urticae with LC50 723.71 and 865.68 μg · ml−1 and the toxicity increased by 54.15 and 52.69% for immature and adult mites, respectively. There were no toxic effects or mortality of rats treated with rosemary nanoemulsion. High acaricidal activity, stability, and safety of rosemary nanoemulsion make this nanoformulation a possible green and nano-acaricidal product. Further studies under field conditions are necessary to study the acaricidal efficiency of rosemary nanoemulsion against two-spotted spider mites and the toxic effect on predacious mites.

Resistance genes in response to root-knot nematode (Meloidogyne javanica) infection suppress one or more of several critical steps in nematode parasitism and their reproduction rate. The reaction of seven commercial tomato genotypes to M. javanica infection was investigated under greenhouse conditions. Current results classified these genotypes as: three resistant (Jampakt, Malika and Nema Guard), one moderately resistant (Fayrouz), and three susceptible (Castle Rock, Super Marmande and Super Strain B). Except Nema Guard, nematode infection significantly reduced plant height, fresh and dry weights of shoots of the other tomato genotypes. Leaf area was significantly reduced for all examined tomato genotypes except Malika and Nema Guard. Total chlorophyll was reduced in all tested tomato genotypes except Jampakt. Infection parameters of M. javanica and their population were significantly reduced on all nematode-resistant tomato genotypes compared to the susceptible genotypes. Also, the maturation rate of M. javanica was suppressed in the resistant genotypes compared to the susceptible genotypes. These results were confirmed by histological study that illustrated a delay in nematode development and their maturation. Total phenolic content significantly increased in nematode infected roots of both resistant and susceptible genotypes except Malika. Among non-infected roots, Malika showed the highest level of total phenols while after M. javanica infection, Nema Guard revealed the highest level of total phenols. Among infected roots, the highest level of total phenols was recorded in Castle Rock. These results suggested that using nematode-resistant tomato genotypes could provide an efficient and nonpolluting method to control root-knot nematodes.

Humidity is probably the most important abiotic factor influencing life cycles, distribution, survival, and population dynamics of stored product pests. Although most of these pests can complete their life cycles in any given relative humidity, their prolonged development time, as well as decreased emergence rate and fecundity, have been well documented in several previous studies. In the present study, we evaluated the changes in energetic substances (lipids, soluble carbohydrates, glycogen, and proteins) accumulated in different life stages of larvae and adults of Tribolium castaneum in response to different relative humidity levels (5, 12, 22, 30, 45, and 65%). The results showed that young larvae were more susceptible to low relative humidity levels and desiccation stress. Larvae tended to accumulate higher proportions of lipids during earlier stages while their energy content shifted towards proteins with an increase in their age. Adult beetles experienced a significant decrease in their protein content immediately after they initiated reproduction. The importance of these fluctuations in the biology of the red flour beetles was discussed in detail.

Kiwifruit (Actinidia deliciosa) is one of the most significant commercial crops in Iran. In 2015 a destructive disease of kiwifruits was observed in orchards, storage facilities and retail markets, resulting in great economic loss to producers. In this study phenotypic and molecular techniques were applied to characterize the causal agent of kiwifruit rot observed in Mazandaran province, northern Iran. From the similarity among the results of pathogenicity tests, equivalency with standard taxonomic criteria for disease and PCR-based analysis of the ITS region, all the isolates were identified as Botryosphaeria dothidea.