Alternative management of soilborne pathogens of melon crop and detection of multiple viruses from fruit crops
Authors:   , Borges Darlan Ferreira 
Published: December 2024

The cultivation of melon (Cucumis melo L.) is extremely important for the
Brazilian economy. The country is the thirteenth largest melon producer in the world
and the third in Latin America. However, even with high melon production, the
damages triggered by soilborne pathogens cause losses in production and yield and risk
the abandonment of melon cultivated areas. Thus, in order to improve quality and
productivity, it is necessary to develop new techniques that can help in the management
of soilborne pathogens, which are the main drive of losses in melon cultivation. Many
control techniques are already being used to manage such pathogens, such as chemical,
biological control, and the use of natural products; however, little is known about the
use of green manure associated with polyethylene mulch to that end. Therefore, the
objective of this research was to evaluate the effect of incorporating plant materials
(Crotalaria juncea L. and Pennisetum glaucum L.) and commercial products (Compost-
Aid® + Soil-Set®) to efficiently control pathogens transmitted via soil in melon
production. In addition, we evaluated the responses of the soil microbiota (total fungi,
total bacteria, sporulating bacteria, and total actinomycetes) to the above treatments.
Two identical greenhouse experiments were conducted in a completely randomized
design with seven treatments and seven replications. In conclusion, with part of this
work, we were able to generate practical and theoretical information for producers to
facilitate the management of the main soilborne pathogens that cause damage to the
melon root system, optimizing techniques (mulch and green manure) that are already
being used by the melon producers. During the second part my research, which was
carried out in the United States of America (USA), different viruses in fruit trees were
studied. In this study, our main goal was to determine the incidence and prevalence of
grapevine viruses in the New England region vineyards. These viruses can cause losses
of $ 25,000 to $ 40,000 per hectare and even replacement of entire vineyard in cases of
high incidence of the viruses. Many of the grapevine viruses investigated in our study
had previously been found in the state of New York (NY). Based on the proximity of
NY to the New England region and the fact that grape growers from this region buy
much of their plant material from NY nurseries, it was expected that the viruses already
described in NY would be detected in New England. To address this hypothesis, we
partially sequenced specific genes from each virus species identified in our study and
phylogenetically compared those sequences with virus sequences from different origins
in the world and in the U.S. The second part of the research carried out in the USA was
the writing of a review on fig mosaic disease. The USA is the eighth largest fig
producer in the world, around 28,300 tons is produced each year, with the state of
California being the largest producer. Typical fig mosaic disease symptoms such as
chlorotic and yellowish spots, discoloration, deformation, and mosaic patterns on leaves
and fruits have been observed in fig trees for almost a century, but the etiological agents
associated with fig mosaic disease have only been investigated in the last decade.
Twelve viruses - fig leaf mottle-associated virus 1 (FLMaV-1), fig leaf mottleassociated
virus 2 (FLMaV-2), fig leaf mottle-associated virus 3 (FLMaV-3), Arkansas
fig closterovirus-1 (AFCV-1), Arkansas fig closterovirus-2 (AFCV-2), fig mosaic
emaravirus virus (FMV), fig latent virus 1 (FLV-1), fig mild mottle-associated virus
(FMMaV), fig cryptic virus (FCV), fig fleck-associated virus (FFKaV), and fig
badnavirus 1 (FBV-1) - and three viroids - apple dimple fruit viroid (ADFVd), citrus
exocortis viroid (CEVd), ands hop stunt viroid (HSVd) - are associated with the disease.
In this review, we proposed the standardization of the name of each virus, the
conduction of geographic studies of the disease, and the development of isolation
protocols to study these viruses and viroids in vivo. Furthermore, we suggested the
conduction proper disease resistance tests, development of diagnoses assays and
phylogenetic studies