The future of food security in Africa is being severely threatened due to an exponential increase in population, which is almost three times the increase of food production. Maize production is constrained by stem borers which cause significant yield losses. Yield losses can be further compounded by higher temperatures due to climate changes, which are expected to increase the population of maize stem borers. While several methods have been employed in stem borer management, there is still significant damage caused by maize stem borers. This necessitates better control methods including the adoption of recent biotechnological advancement in RNA interference (RNAi) technology. This review highlights evidence of an increase in the stem borer population as well as the foreseen decline in maize production worldwide due to the effects of climatic changes. Furthermore, we have drawn attention to improved methods that have been used to control stem borers in maize production as well as a reluctant acceptance of traditional biotechnology in Africa. Finally, we suggest the application of alternative RNA interference techniques to breed maize for efficient pest control in order to achieve food security, improve nutrition and promote sustainable maize production.

Wheat dwarf virus (WDV) has been one of the most common viruses on cereal crops in Poland in the last years. This single stranded DNA virus is transmitted by the leafhopper spec, Psammotettix alienus (Dahlb.) in a persistent manner. It induces yellowing and streaking of leaves, dwarfing or even death of infected plants. The presence of barley- and wheat-specific forms of WDV (WDV-B and WDV-W) and their vector were previously reported in the country, however the literature data did not include any information on the infectivity of the vector in Poland. A duplex polymerase chain reaction (PCR) procedure was developed and optimized for simultaneous detection and differentiation of both forms in the vector. Two sets of primers amplify 734 bp and 483 bp specific fragments for WDV-W and WDV-B, respectively. The results were verified by a sequencing method. The studies were carried out on insect samples collected in autumn from four different locations in Greater Poland. The results confirmed the presence of WDV-W in the tested samples. They also suggested the concomitant of both forms of the virus in the vector. Additional studies to determine virus-vector relationships should be undertaken.

Many species of Trichoderma produce secondary metabolites such as volatile organic compounds (VOCs) that reduce plant diseases and promote their growth. In this work we evaluated the antagonistic effects of VOCs released by eight strains of two Trichoderma species against Pyrenophora teres Drechsler, the causal agent of barley net blotch. Antagonism was estimated based on the percentage of mycelial growth inhibition according to the confronted cultures method. VOCs extraction and identification were performed by gas chromatography and mass spectrometry, through different methodologies for VOCs emitted by antagonists and pathogens alone or when confronted. VOCs produced by all Trichoderma strains inhibited mycelial growth of the pathogen in a range of 3 to 32%, showing weak and unpigmented mycelia with vacuolization. In addition, P. teres stimulated the release of VOCs by both Trichoderma species. The major groups of VOCs detected were sesquiterpenes, followed by diterpenes, terpenoids and eight-carbon compounds. This is the first report about characterization of volatiles emitted by Trichoderma in the presence of P. teres.

Fluorescent Pseudomonas (FP) is a major group of plant growth promoting rhizobacteria and a well-known synthesizer of siderophores, which imparts a selective advantage on rhizosphere competence and their biocontrol traits. The present study was aimed at examining the factors affecting the production of siderophores and their potential biocontrol traits. Sixteen FP isolates were shortlisted based on their siderophore-producing ability in chrome azural S medium. The isolates were checked for variations in siderophore production under varying incubation times, temperatures, pH, iron (Fe3+) concentrations and mutagens. In addition, the iron binding affinity of siderophores, mycelial inhibition assay and plant growth promotion traits were assessed. Results showed that the siderophore production was highly influenced by the time of incubation, changes in pH, temperature and iron concentration. Chemical characterization showed that the produced siderophores were hydroxamates. Maximum siderophore production was observed at pH 7 whereas UV and EtBr exposure invariably suppressed siderophore production drastically in all isolates. All FPs from maize rhizosphere showed excellent siderophore production which could be due to the competence in strategy-II of the plant rhizosphere and significant growth inhibition on Fusarium oxysporum. Our results suggest the inclination of siderophores to iron, in terms of various criteria affecting production and the possible role of environmental mutations that affect the natural iron harvesting mechanism.

The use of Bacillus thuringiensis (Bt) to control insect pests has already been established in various agronomic and forest crops. It is a bacterium that does not pollute the environment, is safe for mammals and vertebrates, lacks toxicity to plants and specifically targets insects. To date in-depth studies have not been conducted about the use of Bt to control the main pest of mahogany (Swietenia macrophylla King) and other Meliaceae species, the Hypsipyla grandella Zeller (Lepidoptera: Pyralidae). Therefore, this study aimed to test the pathogenicity of Bt strains on H. grandella caterpillars, as well to determine the lethal concentration required to kill 50% of the population (LC50) of the most promising strains. Ten strains of Bt toxic to lepidopteran proven in previous trials were used and these were incorporated into a natural diet with mahogany seeds to check their mortality. The LC50 of the top five strains was determined. The results indicate that H. grandella is highly susceptible to Bt toxins and the S1905 strain is highly toxic. Therefore, the use of Bt strains may be a tool to be incorporated into the integrated management of this important pest.

Arbuscular mycorrizal (AM) fungi may enhance plant growth and polyphenol production, however, there have been limited studies on the relationships between root colonization of different fungal species and polyphenol production on cultivated Allium porrum (garden leek). The effects of inoculation of AM fungi spores from Rhizophagus intraradices, Giga -spora margarita, Glomus geosporum, Paraglomus occultum, Claroideoglomus claroideum, and Glomus species on colonization of garden leek roots and symbiotic changes in polyphenol production and plant growth were evaluated in greenhouse experiments. There were significant differences (p < 0.05) in colonization of leek roots by AM fungi species. The greatest level of root colonization was recorded on plants inoculated with R. intraradices (73%) and the lowest level on C. claroideum (3.2%). Significant differences (p < 0.05) in plant height were recorded between AM inoculated plants and the controls. Polyphenol levels differed significantly (p < 0.05) between garden leek plants inoculated with AM fungi and the non-inoculated controls. The percentage increases in polyphenol (a derivative of kaempferol) on garden leeks inoculated with G. geosporum relative to the untreated controls ranged from 28 to 1123%. Due to symbiosis with different AM species, other polyphenols decreased in some instances (negative values) and increased in others for values of up to 590%. Results showed that AM fungi species exhibited remarkable differences in polyphenol levels in garden leeks. The high polyphenol production by garden leek plants inoculated with G. geosporum, and Glomus species could be exploited for enhanced resistance of garden leeks to insects and diseases. This research highlights an understudied area, notably the relationships between AM fungal inoculations, root colonizations and polyphenol production in garden leeks. The findings can be utilized to improve pest resistance and the quality of garden leek plants.