The Spread of the Soil-Borne Pathogen Fusarium solani in Stored Potato Can Be Controlled by Terrestrial Woodlice (Isopoda: Oniscidea)

Fusarium solani, a soil-borne pathogen of stored potato may be disseminated, and thus, the damage caused by the pathogen may be aggravated by the grazing activities of arthropods. To investigate whether terrestrial woodlice contribute to the spread or, instead, to the control of F. solani, we launched a series of pilot experiments. First, a laboratory feeding trial was set up to find whether and to what extent woodlice consume the mycelia of fungal pathogens, namely, Aspergillus niger, F. solani, Macrophomina phaseolina, and Sclerotinia sclerotiorum. This was followed by a second set of experiments to simulate storage conditions where potato tubers, either healthy or infected with F. solani, were offered to woodlice. We found that: (1) F. solani was accepted by woodlice but was not their most preferred food source; (2) the presence of woodlice reduced the spread of F. solani among potato tubers. Our results suggest that the classification of terrestrial woodlice as “storage pests” needs re-evaluation, as isopods have the potential to disinoculate infective plant remnants and, thus, reduce the spread of storage pathogens.

Study on Gas Chromatographic Fingerprint of Essential Oil from Stellera Chamaejasme Flowers and Its Repellent Activities against Three Stored Product Insects

The objective of this study was to establish the chromatographic fingerprints of the essential oil (EO) from Stellera chamaejasme flowers collected from various natural sites by gas chromatography (GC) combined with chemometric methods. The EO was obtained by hydrodistillation, and its chemical composition was analyzed by gas chromatography−mass spectrometry (GC−MS). Most components were identified as ketones and the relatively high-content components were fitone (38.973%), n-hentriacontane (5.807%), myristic acid (4.944%) and phytol (3.988%). In addition, the repellent activities of the EO from S. chamaejasme flowers and its four main chemical compounds were evaluated against three stored product pests (Tribolium castaneum, Lasioderma serricorne, Liposcelis bostrychophila) for the first time. In this work, the EO and the four chemical compounds showed a repellent effect against three storage pests after 2 and 4 h exposure. The experimental method and repellent activity of S. chamaejasme flower EO could provide a basis for the development of botanical pesticide and the utilization of the rich plant resources of S. chamaejasme in the future.

​Advances in Molecular Breeding for Bruchid (Callosobruchus spp.) Resistance in Mungbean [Vigna radiata (L.) Wilczek]: A Review

Mungbean is one of the most important grain legumes with high-quality dietary protein in India as well in many other Asian countries. But the crop is severely affected by bruchids (Callosobruchus spp.) from field to storage condition. These storage pests not only affect the yield but also reduce the market value and quality of the crops. The chemical method of bruchid management is not economical and environmentally unsafe. So, the host-plant resistance to bruchids would be the best alternative and most sustainable way to control the bruchid. A very limited number of wild accessions and cultivated genotypes are available for the transfer of bruchid resistance gene through conventional breeding. Thus, insights into the molecular mechanism of resistance will help to find out the resistance genes/QTLs easily with the support of available genome sequence and that can be introgressed to the cultivated varieties through marker-assisted backcross breeding (MABB) approach. Therefore, in this review, we focused on QTL mapping, identification of novel QTLs, marker assisted-selection, genomics and transcriptomics study by using advanced molecular tools which will be very helpful for genomic-assisted breeding in mungbean for bruchid resistance.

Abundance and diversity of insects associated with stored grains and tamarind in Nigeria

Detailed information on insect pests of stored grains in Nigeria is lacking. A two-year survey was conducted to determine the species composition and abundance of insects associated with maize, millet, rice, sorghum and tamarind in eighteen locations across five agro-ecological zones in Nigeria. Sixteen coleopteran, lepidopteran and hymenopteran species were associated with stored products, with high species richness on cereal grains but low species richness on tamarind. Most of these insects are polyphagous on cereal grains, whereas the tamarind weevil Sitophilus linearis (Herbst, 1797) (Curculionidae), and Caryedon serratus (Oliver, 1790) (Chrysomelidae) were found only on tamarind in this study. The maize weevil Sitophilus zeamais (Motschulsky, 1758), rice weevil Sitophilus oryzae (Linneaus, 1763), lesser grain borer Rhyzopertha dominica (Fabricius, 1792) (Bostrichidae), rusty grain beetle Cryptolestes ferrugineus (Stephens, 1831) (Laemophloeidae) and red flour beetle Tribolium castaneum (Herbst, 1797) (Tenebrionidae) were most abundant on stored grains. The tamarind weevil, C. serratus and the sawtoothed grain beetle Oryzaephilus surinamensis (Linneaus, 1758) (Silvanidae) were most abundant on tamarind. The hymenopterans Theocolax elegans (Westwood, 1874) (Pteromalidae), Anisopteromalus calandrae (Howard, 1881) (Pteromalidae) and Cephalonomia waterstoni (Gahan, 1931) (Bethylidae) were the dominant parasitoids of larvae and pupae of the storage pests. Simpson index of diversity of insect species across locations ranged from low (0.63) to high (0.89).

Chemical Constituents of the Essential Oil Extracted from Elsholtzia densa and Their Insecticidal Activity against Tribolium castaneum and Lasioderma serricorne

Storage pests pose a great threat to global food security. Here, we found that the essential oil (EO) extracted from E. densa possesses obvious effects against the insects that threaten stored-products. In this work, we investigated the chemical constituents of the essential oil extracted from Elsholtzia densa, and their insecticidal (contact and fumigant) toxicity against Tribolium castaneum and Lasioderma serricorne. A total of 45 compounds were identified by GC-MS, accounting for 98.74% of the total EO. Meanwhile, 11 compounds were isolated from the EO, including limonene, β-caryophyllene, ρ-cymene, trans-phytol, α-terpineol, linalool, acetophenone, 1,8-cineole, ρ-cymen-7-ol, 1-O-cerotoylgly-cerol, and palmitic acid. Furthermore, acetophenone, ρ-cymen-7-ol, and 1-O-cerotoylgly-cerol were isolated for the first time from Elsholtzia spp. The results of the bioassays indicated that the EO had the property of insecticidal toxicity against T. castaneum and L. serricorne. All of the compounds showed different levels of insecticidal toxicity against the two species of insects. Among them, 2-ethyl-1H-imidazole had no insecticidal toxicity against T. castaneum, but possessed fumigant and obvious contact toxicity against L. serricorne. ρ-Cymen-7-ol had beneficial insecticidal toxicity against the two species of insects, and fumigant toxicity against L. serricorne. ρ-Cymen-7-ol (LD50 = 13.30 μg/adult), 1-octen-3-ol (LD50 = 13.52 μg/adult), and 3-octanol (LD50 = 17.45 μg/adult) showed significant contact toxicity against T. castaneum. Acetophenone (LD50 = 7.07 μg/adult) and ρ-cymen-7-ol (LD50 = 8.42 μg/adult) showed strong contact toxicity against L. serricorne. ρ-Cymene (LC50 = 10.91 mg/L air) and ρ-cymen-7-ol (LC50 = 10.47 mg/L air) showed powerful fumigant toxicity to T. castaneum. Limonene (LC50 = 5.56 mg/L air), acetophenone (LC50 = 5.47 mg/L air), and 3-octanol (LC50 = 5.05 mg/L air) showed obvious fumigant toxicity against L. serricorne. In addition, the EO and its chemical compounds possessed different levels of repellent activity. This work provides some evidence of the value of exploring these materials for insecticidal activity, for human health purposes. We suggest that the EO extracted from E. densa may have the potential to be developed as an insecticidal agent against stored product insect pests.

Insecticidal Effect of Eucalyptus Essential Oils on Mortalities of Storage Pests of Grains Sitophilus oryzae and Sitophilus granarius in the Region of Tissemsilet Algeria

Background: Stored cereals are attacked by pests including Sitophilus, a primary insectpestthat kthe whole grain and destroys the germ. The usual control methods are less efficient and more expensive. The use of essential oils of aromatic plants is more interesting. Eucalyptus is a plant of great medicinal value due to the presence of secondary metabolites. Methods: In this experimentation that took place during the year 2017, extraction of oils by hydro distillation of eucalyptus was used on insects at different doses by two methods with are ingestion and inhalation. Two species of Sitophylus are morphologically different as they may be different with regard to the use of biopesticide (eucalyptus essential oil), regarding the mortality rate in relation to the duration of treatment Result: Sitophilus oryzae was more sensitive to this bio-pesticide since it was only after eight (08) hours of treatment that mortality exceeded 50% by the ingestion method whereas only 6.6% of mortality was recorded on Sitophilus granarius. Same observation by the inhalation method, 90% mortality on the third day for Sitophilus oryzae while only 20% mortality on Sitophilus granarius. So the ingestion method requires fewer products plus a speed in the mortality time.

Chitosan That Renewable Film and Coatings, Evaluation in Terms of Drosophila

The dried mulberry (Morus alba) is among the fruits that occurrence a high risk of storage pests due to its high sugar content. Coating materials slow down the chemical spoilage that will occur in foods. The effect of the coating material used in the study on mulberry and Drosophila melanogaster was determined. The insect’s weight, texture, and biochemical analysis (Total oxidant- TOS; total antioxidant levels-TAS; oxidative stress index-OSI; Glutathione-S-transferase-GST and Catalase-CAT enzymes) were determined as a result of the application. In terms of weight, it was observed that the weight of individuals fed with 1% chitosan-coated mulberry was higher in female and male individuals. In terms of texture, the highest hardness was measured in males fed 0.2% chitosan and females fed 1% chitosan. Because of the biochemical analysis, the insect does not create resistance. The GST, CAT and TAS enzymes are synthesized close to normal. The OSI is low without increasing TOS, indicating that 1 and 2% coated mulberries are usable in environments and insects.