Due to the high market value of cashew nut, cashew became a significantly important cash crop in many countries. Originating from Brazil, the plant was introduced into Africa, India, and Southeast Asia and is nowadays found across most of the tropical regions. However, the diseases that threaten and compromise crop production have not yet been comprehensively documented. The aim of this study was to examine the published scientific data on cashew diseases, to identify current knowledge gaps, and to present a review of the most important diseases and pathogens affecting cashew productivity. The most described diseases are caused by fungi genera—mainly Colletotrichum, Lasiodiplodia, and Erysiphe (worldwide); Cryptosporiopsis (East Africa); and recently Fusarium in Tanzania. Other fungal genera (e.g., Septoria, Pilgeriella, and Pestalotia) may correspond to emerging local cashew diseases that have not yet expanded to other geographic regions or for which records are lacking. Gummosis (Lasiodiplodia spp.), which is considered the most prevalent and damaging disease of cashew, has a pantropical distribution. There is large discrepancy concerning the causal agents of cashew diseases that might be explained by the lack of proper species identification through morpho-cultural and molecular approaches. This, in turn, can easily lead to misdiagnoses that have serious negative consequences for the implementation of specific control actions. It is important to establish a standardized identification workflow that will allow a reliable identification of the disease-causing agent and to determine the occurrence and/or expansion of a given pathogen across cashew-producing regions.

Cashew is an important export-oriented crop in several tropical countries, often under monocropping systems. Intercropping with legume species is promoted as a sustainable practice, enhancing agricultural productivity and providing nutritional food sources to rural communities. This study aimed to characterize the diversity of Leguminosae (or Fabaceae) in the cashew agroforestry systems of East Timor (Southeast Asia). Fourteen cashew orchards were sampled across the country, and information about leguminous species uses was collected from local populations. About 50 species are commonly part of the country’s cashew agroforestry system, many of them simultaneously used as food, fodder, and in traditional medicine. Six bean species—Cajanus cajan (L.) Huth, Phaseolus lunatus L., Phaseolus vulgaris L., Vigna angularis (Willd.) Ohwi and H.Ohashi, Vigna radiata (L.) R.Wilczek and Vigna unguiculata (L.) Walp.—are largely used as food. The mineral contents of these beans revealed relevant differences between species and, in some cases, between types (seed colour) within species. Periods of hunger and low food variety are frequent in East Timor, reflecting a very poor nutritional state of the population. Knowing and using legumes for local nutrition, as well as for healthcare and well-being, adds great value to these species as components of East Timor cashew agroforestry systems.

Background Cashew (Anacardium occidentale L.) is a crop currently grown in several tropical countries because of the economic importance of cashew nuts. Despite its enormous economic worth, limited research has been conducted on the molecular diversity of cashew genetic resources. In this study, a wide comprehensive assessment of the genetic diversity of cashew trees in East Timor was performed using microsatellites (SSRs) to evaluate intraspecific diversity and population structuring. Methods A total of 207 individual cashew trees, including trees from East Timor (11), and outgroup populations from Indonesia (one) and Mozambique (two), were analyzed with 16 cashew-specific SSRs. A comprehensive sampling of cashew trees within East Timor was performed, covering the distribution of cashew orchards in the country. Genetic diversity indices were calculated, and population structuring was determined using three different approaches: genetic distances (UPGMA and NJ), AMOVA, and individual-based clustering methods through Bayesian (STRUCTURE) and multivariate (DAPC) analyses. Results The population structuring analysis revealed that the genetic diversity of cashew populations in East Timor was higher in this study than previously reported for cashew trees. A higher allelic richness was found within cashew populations in East Timor compared with the outgroup populations (Mozambique and Indonesia), reinforced by the presence of private alleles. Moreover, our study showed that cashew populations in East Timor are grouped into two dissimilar genetic groups, which may suggest multiple cashew introductions over time. These new cashew genetic resources could be explored for future crop improvement. Conclusions Crop diversity underpins the productivity, resilience, and adaptive capacity of agriculture. Therefore, this study provides useful information regarding genetic diversity and population structure that can be harnessed to improve cashew production in East Timor. This data is also important to creating a country-specific genetic cashew signature to increase cashew market value.