Onion yellow dwarf virus (OYDV), an aphid-borne potyvirus is one of the major viral pathogens of garlic causing significant yield losses worldwide. It is found almost everywhere in the world where Allium species is grown. The aim of this study was to test the presence of OYDV infection in garlic from Ethiopia. The presence of the virus was tested by Reverse transcription polymerase chain reaction (RT-PCR). The direct sequencing of the PCR product produced a sequence of 296 bp. Sequence analysis showed 89.27% sequence homology with an isolate from Australia (HQ258894) and 89.29% with an isolate from Spain (JX429964). A phylogenetic tree constructed with MEGA 7.0 revealed high levels of homology with various isolates of OYDV from all over the world and thus further confirmed the identity of the virus.
The species Halyomorpha halys (Stål), which is endemic in East Asia, was first detected in North America in 1996 and was probably introduced into Europe in 2008. The species is polyphagous. It consumes over 170 host plant species and significantly impacts crop production. In Greece the first recording of its presence was in 2014, when it was reported as a nuisance in houses in the region of Athens. The present study describes the systematic spread and damage of this invasive pest, including the first recorded identification in peach and olive cultivations in the prefecture of Imathia in central Macedonia, Greece. Sampling was carried out in representative peach and olive farms during July and August, 2018 and 2019 in which significant levels of fruit damage were recorded, especially during 2018. The population of the species was recorded throughout the winter seasons of 2018 and 2019 in which overwintering adults were systematically recorded in shelters and other constructions near fruit orchards. Given the dynamics of the species and its destructive impact on a wide range of host species, H. halys is expected to be a major pest. Additionally, considering that the prefecture of Imathia is the most important peach growing area of Greece, further studies of the presence and population dynamics of this species along with the establishment of particular management actions to control the population is imperative for the future protection of horticultural production in Greece.
In this short communication describing experiments carried out on the larvae of two insects, Unaspis euonymi Comstock (feeding on Euonymus japonicus Thunb.) and Dynaspidiotus britannicus Newstead (feeding on Laurus nobilis L.), we evaluate for the first time the efficiency of using DNA insecticides in the control of sap-sucking insects, including armored scale insects. Over a period of 10 days, high insect mortality was detected in both U. euonymi and D. britannicus, accompanied by a significant decrease in the concentration of target RNAs. At the same time, no visible changes were observed when the leaves of the host plants were subjected to treatment with DNA insecticides for one month. The results show the high efficiency of DNA insecticides used against hemipteran insect pests. It is noteworthy that the high efficiency of DNA insecticides and their low cost in comparison with RNA preparations provides a safe and extremely promising potential vehicle for the control of sap-sucking insects.
The yellow sugarcane aphid (YSA), Sipha flava Forbes (Homoptera: Aphididae) is an invasive insect pest of many graminaceous plants which include cultivated crops, like sorghum, sugarcane, rice, maize and several species within non-cultivated genera e.g. Digitaria, Panicum, Paspalum, and Pennisetum. A survey conducted in the Kagera region indicated an infestation by YSA in nine sugarcane varieties grown. This pest causes damage to leaves leading to yellow, purple and red discoloration. This is the first report of YSA infestation in the Tanzanian sugarcane industry. Efforts to develop control measures are still in progress.
5.8S ribosomal RNA plays an important role in protein synthesis and eukaryotic ribosome translocation. Contact DNA insecticides based on antisense fragments of 5.8S ribosomal RNA gene of gypsy moth Lymantria dispar L. showed prospective insecticidal activity on its larvae. The most pronounced insecticidal effect was found for antisense fragments 10 and 11 nucleotides long (oligoRIBO-10 and oligoRIBO-11), whereas 12 nucleotides long fragment (oligoRIBO-12) caused the lowest level of insect mortality. This data corresponds to results obtained earlier using rabbit reticulocyte and wheat germ extracts, where maximum inhibition of protein synthesis was observed when a relevant oligomer 10-11 nucleotides long was used, whilst longer chain lengths resulted in reduced inhibition. Using oligoRIBO-11 fragment we have shown penetration of antisense oligonucleotides to insect cells through insects’ exoskeletons. MALDI technique registered the penetration of the oligoRIBO-11 fragment into insect cells after 30 min and a significant response of insect cells to the applied oligonucleotide after 60 min, which indicates not only that the oligonucleotide enters the insect cells, but also the synthesis of new substances in response to the applied DNA fragment. Contact DNA insecticides developed from the L. dispar 5.8S ribosomal RNA gene provide a novel biotechnology for plant protection using unmodified antisense oligonucleotides.
Obviously, the moment has come in agriculture and forestry when we must decide to gradually abandon (where possible) non-selectively acting chemical insecticides, taking into consideration the overall decrease in the total biomass of insects, especially pollinators, and the increased number of diseases and human deaths directly or indirectly associated with chemical insecticides. Yet with the world facing the rapid growth of human populations, the annual reduction of cultivated areas, and substantial losses from insect pests, most experts believe that no serious alternative to chemical insecticides exists. However, there is definitely room to create more well-tailored chemical insecticides. And there is hope, in the form of effective DNA insecticides able to provide an adequate level of safety for non-target organisms. In this short communication describing experiments carried out on the larvae of Ceroplastes japonicus Green (feeding on Ilex aquifolium Linnaeus), we show for the first time the enormous potential for the use of DNA insecticides in the control of soft scale insects and how they could replace non-selective organophosphate insecticides.
The genus Cnephasia is represented by more than 70 species of insects worldwide, including serious pests of agricultural plants, mainly cereals. Since members of this genus are frequently very similar externally, species determination based on morphotaxonomy is time-consuming and difficult, especially for non-taxonomists. Hence, it could possibly be replaced by molecular biology approaches. A short nucleotide sequence of mitochondrial cytochrome oxidase I (mtCOI) constitutes a commonly used molecular marker for phylogenetic analyses identification. The aim of this work was molecular species determination of leaf rollers, collected in Poland, that on the basis of external features were hardly distinguishable. We amplified, sequenced and phylogenetically studied the fragment of the mtCOI gene for each individual. Comparative analyses showed the highest nucleotide similarity to C. genitalana, C. longana, C. pasiuana, C. asseclana and C. stephensiana, which was also confirmed by phylogeny. Obtained results showed genetic variation of the analyzed fragment of the mtCOI gene between analyzed Cnephasia spp. found in Poland that can be helpful in proper species determination. This in turn, may be essential for successful biological control and pest monitoring in crop cultivation.
The efficacy of the fungus Lecanicillium lecanii and two bacteria, Bacillus thuringiensis and Streptomyces avermitilis against the two-spotted spider mite Tetranychus urticae Koch and side effects on its predatory mite Phytoseiulus persimilis A.-H. was studied under laboratory conditions. Both S. avermitilis and B. thuringiensis based biopesticides resulted in maximum mortality rates of 90–100% and 91–99% for spider mite adults and larvae, respectively. The mortality of spider mite larvae under fungus L. lecanii treatment was around 60%. These bacteria and fungus also had toxic effects against P. persimilis on the same day of applying insecticides and releasing the predatory mite. The release of predatory mites one day post-treatment of plants with L. lecanii and 7 days post-treatment with B. thuringiensis or S. avermitilis did not negatively affect the survival of predators released. These findings support the potential use of entomopathogenic fungi and bacteria in combination with predatory mites in spider mite biocontrol.
Biocomposite foam scaffolds of poly(ε-caprolactone) (PCL) with different porogenes were produced with batch foaming technique using supercritical carbon dioxide (scCO2) as a blowing agent. In performed experiments composites were prepared from graphene-oxide (nGO), nano-hydroxyapatite (nHA) and nano-cellulose (nC), with various concentrations. The objective of the study was to explore the effects of porogen concentration and foaming process parameters on the morphology and mechanical properties of three-dimensional porous structures that can be used as temporary scaffolds in tissue engineering. The structures were manufactured using scCO2 as a blowing agent, at two various foaming pressures (9 MPa and 18 MPa), at three different temperatures (323 K, 343 K and 373 K) for different saturation times (0.5 h, 1 h and 4 h). In order to examine the utility of porogenes, a number of tests, such as static compression tests, thermal analysis and scanning electron microscopy, have been performed. Analysis of experimental results showed that the investigated materials demonstrated high mechanical strength and a wide range of pore sizes. The obtained results suggest that PCL porous structures are useful as biodegradable and biocompatible scaffolds for tissue engineering.