In Antarctic summer 1983/1984 samples of planktonie and attached diatoms were collected in the Admiralty Bay (King George Island, South Shetland Islands) as well as samples of planktonie diatoms in the region of South Orkneys, Drake Passage and Bransfield Strait (BIOMASS-SIBEX Project). Using gas chromatography residues of chloroorganic pesticides, namely the compounds of the DDT group and HCH isomers were determined. It was found that the highest values of the content of these compounds occurred in attached diatoms coming from areas continuously washed with water from the melting glacier, in planktonie diatoms from the samples of the Admiralty Bay and from strongly glaciated regions. A hypothesis was put forward that along with the direct atmospheric transport the release of the deposits of these compounds from ice and glaciers during their melting is an additional source of input of chloroorganic biocides into Antarctic waters. Diatoms are good indicators of this process.

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.

Annual losses of cocoa in Ghana to insect pests are significant. The use of integrated pest management (IPM) tools is critical for effective pest management. Previous studies on the subject have considered how farmers perceive the economic impact of insect pests on cocoa. These studies however did not investigate farmers’ ability to identify pests, associated damage symptoms and their implications for pest management. The current study, therefore, assessed farmers’ ability to correctly associate insect damage with the pest species that caused it. A total of 600 farmers were interviewed in the Eastern, Ashanti, Western, Brong Ahafo and Central Regions of Ghana with a structured open and closedended questionnaire. Most farmers (>85%) were unable to correctly identify and associate pests to their damage. The majority (>80%) of farmers also could not link the immature stages of insect pests to their adult stages. Wrong identification of the major pests (>85%) led to a wide variation in the timing of insecticide application amongst farmers. The majority of the farmers (60%) interviewed had not received training in insect pest identification. The study shows that 90% of the farmers, who had received some training, got it from the Cocoa Health and Extension Division (CHED) of the Ghana Cocoa Board (COCOBOD). Almost all respondents (98%) agreed that correct pest identification is critical for effective pest control. The importance of pest identification and monitoring as a component of IPM is discussed.

The study’s objective was to assess the efficacy and to identify the toxic mechanisms of action of some plant-derived monoterpenes and yucca extract as alternatives to chemical insecticides against the red flour beetle, Tribolium castaneum. Carvone, 1,8-cineole, cuminaldehyde, and linalool, as well as Yucca schidgera extract, were the control agents whose efficacy against the red flour beetle was tested in the laboratory and compared to malathion. The criteria for evaluating efficacy were the effects of the tested compounds on adult mortality and red flour beetle progeny. Furthermore, the effects of the control agents on some enzymes (Acetylcholinesterase, ά-amylase, and alkaline phosphatase) in T. castaneum were investigated. Moreover, the effect of the tested control measures on weight loss of treated wheat grain was studied. The tested substances showed a high ability to control T. castaneum with regard to adult mortality and offspring production, especially when used as fumigants. For adult mortality, malathion showed the highest potential against T. castaneum as a fumigant, followed by carvone, yucca extract, cuminaldehyde, linalool, and 1,8-cineole with LC ₅₀ values of 0.05, 331.5, 365.1, 372.2, 460, and 467.5 mg · 1000 cm ^–2 after 72 hours, respectively. The highest reduction in progeny was for malathion followed by carvone, linalool, cineole, yucca extract, and cuminaldehyde with reduction percentages of 100, 90, 89.3,79.4 and 65.8%, respectively. The tested compounds significantly affected acetylcholinesterase activity, alpha-amylase activity, and alkaline phosphatase in the red flour beetle. There was no significant reduction in the weight of wheat grains treated with the tested materials compared to the untreated healthy grains. Finally, the tested compounds as fumigants, especially 1,8-cineole, can be considered as effective alternatives to control the red flour beetle.

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.

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.