Over the years, several agricultural interventions and technologies have contributed immensely towards intensifying food production globally. The introduction of herbicides provided a revolutionary tool for managing the difficult task of weed control contributing significantly towards global food security and human survival. However, in recent times, the successes achieved with chemical weed control have taken a turn, threatening the very existence we have tried to protect. The side effects of conventional farming, particularly the increasing cases of herbicide resistance agricultural weeds, is quite alarming. Global calls for sustainable weed management approaches to be used in food production is mounting. This paper provides detailed information on the molecular biological background of herbicide resistant weed biotypes and highlights the alternative, non-chemical weed management methods which can be used to prevent the development and spreading of herbicide-resistant weeds.

The use of pesticides dominates agriculture today, but unfortunately poses several threats to the environment and humans, through bioaccumulation and biomagnification. This research tested the efficacies of Salvia officinalis subsp. lavandulifolia and Salvia officinalis subsp. major aqueous extracts against Botrytis cinerea in order to curb chemical control and subsequent reduction in their threats. The leaves of Salvia officinalis subsp. lavandulifolia and Salvia officinalis subsp. major were collected in July and September 2019 and shed-dried. Then 90 ml hot distilled water was added to10 g of the crumbled leaves from each sample, left for 24 hours and the filtrate was used to prepare two different media concentrations: CC1 containing 99 ml PDA (i.e. Potato Dextrose Agar) and 11 ml extract (or ion-exchange water as control 1); and CC2 containing 88 ml PDA and 22 ml extract (or ion-exchange water as control 2). The 10 ml from each mixture (CC1, CC2 and the controls) was used as the growth media in 5 replications. Each Petri dish was centrally inoculated with 9 mm2 B. cinerea mycelia, and the area of colony was taken. All the extracts effectively inhibited the growth of Botrytis cinerea, with Som2 showing the highest inhibition. In Salvia officinalis subsp. lavandulifolia, Sol1 (July harvested) showed higher inhibition (53.90%) compared to September harvested Sol2 (40.78%) in CC2 at 3 days post inoculation (PI), while in Salvia officinalis subsp. major, Som2 (September harvested) showed higher inhibition (15.01%) compared to July harvested Som1 (0.04%) in CC1 at 7 days PI. Generally, CC2 showed higher inhibition compared to CC1.

In 2019, random samples of Panicum miliaceum growing as a weed were surveyed to uncover their virus infections at two locations in Hungary. This pilot study revealed infection with three viruses, two appearing for the first time in the country. As follow-up research, in the summer of 2021, we collected symptomatic leaves of several monocotyledonous plants in the same locations and determined their viromes using small RNA high-throughput sequencing (HTS). As a result, we have identified the presence of wheat streak mosaic virus (WSMV), barley yellow striate mosaic virus (BYSMV), barley virus G (BVG), and two additional viruses, namely Aphis glycines virus 1 (ApGlV1) and Ljubljana dicistrovirus 1 (LDV1), which are described for the first time in Hungary. New hosts of the viruses were identified: Cynodon dactylon is a new host of BYSMV and LDV1, Echinocloa crus-galli is a new host of BVG, ApGlV1 and LDV1, Sorghum halepense is a new host of ApGlV1, and Panicum miliaceum is a new host of LDV1. At the same time, Zea mays is a new host of ApGlV1 and LDV1. Small RNA HTS diagnosed acute infections but failed to detect persistent ones, which could be revealed using RT-PCR. The infection rates at the different locations and plant species were different. The phylogenetic analyses of the sequenced virus variants suggest that the tested monocotyledonous weeds can host different viruses and play a virus reservoir role. Viral spread from the reservoir species relies on the activity of insect vectors, which is why their management requires an active role in plant protection strategies, which need careful planning in the changing environment.

In crop fields, weeds are perfect hosts for plant pathogenic viruses. The effects of these viruses can range from latent infection to plant death, affecting crop quality and yield and leading to economic loss in the world. Virus infection threatens cereals used as food for most of the world’s population. Weeds growing in cereal fields can compete for essential supply and act as virus reservoirs, strengthening their deteriorating effect. In this review, we collected the current information on viruses presenting in the most important monocotyledonous weeds: Echinocloa crus-galli, Setaria viridis, Cynodon dactylon, Sorghum halepense and millet species growing as weeds. Identifying plant viruses in monocotyledonous weed hosts provides more information about viral infection flow and guides the development of management strategies for safeguarding our field crops.

Clematis vitalba L. is a climbing shrub and a pioneer plant in abandoned orchards or vineyards that are widespread in temperate climate zones. In past years, several viruses infecting the Clematis species have been identified, including different ilarviruses. Prunus virus I (PrVI) is a recently described ilarvirus, which has been shown to infect sweet cherries and peaches in Greece. Moreover, its presence has been detected in ornamental Clematis in Russia. In the present work, we analyzed the virome of wildly growing C. vitalba plants from Hungary, Slovakia and Croatia showing different kinds of symptoms using high-throughput sequencing (HTS) of small RNAs or ribodepleted RNAs. Applying HTS enabled us to identify the presence of PrVI in C. vitalba, and the bioinformatic analyses were further validated with RT-PCR using PrVI-specific primers and Sanger dideoxy sequencing. Nearly full genome sequences of all three viral RNAs of one Hungarian, two Slovak and one Croatian isolate were determined. Their phylogenetic analysis showed high similarity to each other and to other PrVI isolates described from Central Europe. As the sampled plants were co-infected with other viruses, it is not possible to determine a direct correlation between the infection with PrVI and the observed symptoms. Analyses of different Prunus species in stock collection showed infection of several peach and sweet cherry varieties in Hungary. Our results expand the knowledge on the natural host range of PrVI and highlight the necessity to evaluate alternative plant hosts (even non-Prunus) of PrVI and the role of the virus in the etiology of the potential diseases.