Fungal communities in above-ground tree tissues are hyperdiverse and are influenced by biotic interactions with other organisms living in or on these tissues. These biotic interactions are, however, ...still poorly understood. In this study, we aimed to understand how insect-associated gall formation on
foliage correlates with the diversity of foliar fungal communities in surrounding healthy leaf tissue, as well as the co-occurrence patterns among the members of the fungal community. We used ITS metabarcoding to characterise the foliar fungal communities of 179 individual
trees. These trees were assigned to infestation levels of the wasp
(Eulophidae: Hymenoptera), which causes gall formation on shoot tips and leaves of its host. Fungal community networks were calculated using a Pearson correlation coefficient. The composition and diversity of fungal communities were influenced by the severity of
infestations. We identified potential
pathogens with high sequence abundance at all disease severity levels, but network analysis indicated that the co-occurrence of potential pathogens between no to mild and medium to heavy infestation differed significantly. A better understanding of microbial interactions, especially the role of pathogens, can be useful for controlling disease- and beneficial host-associated microbial communities.
Wolbachia is a bacterial endosymbiont of many arthropod and nematode species. Due to its capacity to alter host biology, Wolbachia plays an important role in arthropod and nematode ecology and ...evolution. Sirex noctilio is a woodwasp causing economic loss in pine plantations of the Southern Hemisphere. An investigation into the genome of this wasp revealed the presence of Wolbachia sequences. Due to the potential impact of Wolbachia on the populations of this wasp, as well as its potential use as a biological control agent against invasive insects, this discovery warranted investigation.
In this study we first investigated the presence of Wolbachia in S. noctilio and demonstrated that South African populations of the wasp are unlikely to be infected. We then screened the full genome of S. noctilio and found 12 Wolbachia pseudogenes. Most of these genes constitute building blocks of various transposable elements originating from the Wolbachia genome. Finally, we demonstrate that these genes are distributed in all South African populations of the wasp.
Our results provide evidence that S. noctilio might be compatible with a Wolbachia infection and that the bacteria could potentially be used in the future to regulate invasive populations of the wasp. Understanding the mechanisms that led to a loss of Wolbachia infection in S. noctilio could indicate which host species or host population should be sampled to find a Wolbachia strain that could be used as a biological control against S. noctilio.
The genus
Botryosphaeria
includes more than 200 epithets, but only the type species,
Botryosphaeria dothidea
and a dozen or more other species have been identified based on DNA sequence data. The ...taxonomic status of the other species remains unconfirmed because they lack either morphological information or DNA sequence data. In this study, types or authentic specimens of 16 “
Botryosphaeria
” species are reassessed to clarify their identity and phylogenetic position.
nu
DNA sequences of four regions, ITS, LSU,
tef1-α
and
tub2
, are analyzed and considered in combination with morphological characteristics. Based on the multigene phylogeny and morphological characters,
Botryosphaeria cruenta
and
Botryosphaeria hamamelidis
are transferred to
Neofusicoccum
. The generic status of
Botryosphaeria aterrima
and
Botryosphaeria mirabile
is confirmed in
Botryosphaeria
.
Botryosphaeria berengeriana
var.
weigeliae
and
B
.
berengeriana
var.
acerina
are treated synonyms of
B. dothidea
.
Botryosphaeria mucosa
is transferred to
Neodeightonia
as
Neodeightonia mucosa
, and
Botryosphaeria ferruginea
to
Nothophoma
as
Nothophoma ferruginea
.
Botryosphaeria foliicola
is reduced to synonymy with
Phyllachorella micheliae
.
Botryosphaeria abuensis
,
Botryosphaeria aesculi
,
Botryosphaeria dasylirii
, and
Botryosphaeria wisteriae
are tentatively kept in
Botryosphaeria sensu stricto
until further phylogenetic analysis is carried out on verified specimens. The ordinal status of
Botryosphaeria apocyni
,
Botryosphaeria gaubae
, and
Botryosphaeria smilacinina
cannot be determined, and tentatively accommodate these species in
Dothideomycetes incertae sedis
. The study demonstrates the significance of a polyphasic approach in characterizing type specimens, including the importance of using of DNA sequence data.
Purpose of Review
Continuous replanting of land with the same or similar plant species can result in the accumulation of harmful soil microbes, which can lead to crop failure. In this review, we ...explore the influence of constant replanting on the health of short-rotation forestry soil, focusing on the accumulation of deleterious microbes and the decline of beneficial microbes. We also suggest possible practical solutions to address this problem and consider future research that could be conducted to better understand and reduce the build-up of deleterious soil microbes in short-rotation forestry soil.
Recent Findings
Compelling evidence that continuous replanting of the same tree species in short-rotation plantation forestry might contribute to the build-up of deleterious soil microbes is still lacking. However, our assessment of existing soil microbiome data from global short-rotation plantation environments suggests a high risk of an accumulation of harmful microbes and a loss of beneficial microbes in plots that were continually replanted with the same tree species. Based on this evidence, and that from agriculture, we propose further research to acquire a better understanding of the build-up of harmful soil microbes in short-rotation plantation forestry, and suggest crop rotation and intercropping strategies to avoid this malady in the future.
Summary
The accumulation of microbes detrimental to plantation trees and the decline of microbes beneficial to these trees are realistic risks when plantations are continually replanted with the same tree species. Extensive research is necessary to evaluate the impact of short continuous planting rotations on the biodiversity of soil microbes in plantations and to develop strategies that would alleviate the build-up of detrimental microbes.
...in fungi, the rate of species discovery outpaces taxonomy, and naming of new taxa is not inherently accompanied by biological information. There are as many as three million (or more) fungal ...species in the world, and, of these, only 80,000 have been described 1. ...a dogma that focuses on the described, well-known species overlooks the remainder and ignores their biosecurity significance.
Knowledge of the biology of a pest is essential for building sustainable management programmes. Pentatomidae have a hemimetabolous life cycle with egg, nymphal, and adult life stages, which differ in ...morphological, ecological, and behavioural traits. Some of these traits, such as mating behaviour, pheromones (alarm and aggregation pheromones) and the acquisition of gut symbionts can be targeted for pest management strategies. Here, we review the available literature on these life history traits of the Pentatomidae with potential for use in management programmes. Pheromone-mediated aggregation and the disruption of symbiont acquisition are two important targets for Pentatomidae control. Other traits such as the use of alarm pheromones for enhancing natural enemies and substrate-borne vibration for mating disruption deserve further consideration. Colour vision and flight ability are still poorly studied, despite their potential importance for stink bug management.
Botryosphaeriaceae represents a diverse family of fungi with a cosmopolitan distribution and a wide host range. We studied species diversity and overlap of Botryosphaeriaceae on selected tree species ...of Anacardiaceae in disturbed (farming or forestry) and undisturbed (isolated and/or protected) ecosystems in the Limpopo and Mpumalanga provinces, South Africa. The disturbed sites resided at Tshikundamalema and Tshipise in Limpopo and the undisturbed sites at Nwanedi and the Mapungubwe National Park in Limpopo and the Kruger National Park in Mpumalanga. Asymptomatic branches were collected from Mangifera indica, Sclerocarya birrea and Lannea schweinfurthii trees in 2017 and 2018. Eleven species were identified using a multi-gene sequencing approach, including Diplodia allocellula, Dothiorella brevicollis, Do. dulcispinae, Do. viticola, Lasiodiplodia crassispora, L. exigua, L. gonubiensis, L. mahajangana, Neofusicoccum parvum, Oblongocollomyces sp. 1 and Oblongocollomyces sp. 2. Ten of the 11 species were identified in undisturbed ecosystems (eight species being unique), while only three species were identified in disturbed ecosystems (one species being unique). Two species were generalists on trees in disturbed and undisturbed ecosystems. Lasiodiplodia mahajangana was the most dominant species as it occurred on the three tree species of Anacardiaceae. Isolates of N. parvum occurred on both S. birrea (a native species) and M. indica (a non-native species) that occurred adjacent to each other in disturbed ecosystems, confirming the ability of this invasive pathogen to cross-infect native and non-native hosts and its abundance in human-disturbed environments. The findings from this study confirm the lack of host specificity for most species of Botryosphaeriaceae. The results also indicate that disturbance through human activity, such as clear-cutting, selective cutting and land-use changes, negatively influences the diversity of the Botryosphaeriaceae.
The invasive ambrosia beetle,
, was first reported in South Africa in 2018. The beetle has now spread to eight provinces of the country and has had a devastating impact on both native and non-native ...tree species. This is especially true for trees located in urban and peri-urban environments. Recent predictions are that the South African
invasion will cost an estimated ZAR 275 billion (approx. USD 16 billion) if it continues to spread uncontrollably, justifying an urgent need for its effective management in the country. One option is biological control, which is preferred over the use of chemicals due to its lower environmental impact. We tested two broad-spectrum fungal entomopathogenic agents, Eco-Bb
and Bio-Insek, which are commercially available in South Africa, for efficacy against
. Initial laboratory assays yielded promising results. However, beetle infestation trials using treated pieces of woody castor bean stems showed little effect on beetle survival and reproduction.
Eucalyptus
is one of the most planted tree genera across the world, but is heavily challenged by invasive insect pests originating from the native range of these trees. The rate of introduction of ...non-native
Eucalyptus
-feeding insects has increased globally, including in sub-Saharan Africa where
Eucalyptus
trees have an important socio-economic role. In this study, we mapped the distribution and examined the genetic diversity of non-native
Eucalyptus
insect pests in 14 countries across sub-Saharan Africa. We focused on five foliage-feeding insect pests of
Eucalyptus
which are known to be present in the region, namely the bluegum chalcid wasp,
Leptocybe invasa
; the redgum lerp psyllid,
Glycaspis brimblecombei
; the bronze bug,
Thaumastocoris peregrinus
; the Eucalyptus weevil,
Gonipterus
sp.n.2; and the Eucalyptus gall wasp,
Ophelimus maskelli
. Insect samples were collected through structured surveys and small-scale sampling which were both combined with published literature to determine the distribution of these insect pests. Genetic diversity of each of these insect pests was estimated/assessed based on mitochondrial cytochrome oxidase I (COI) or cytochrome b (Cyt b) sequence data. Except
O. maskelli
, which is a relatively recent arrival, the other insect pests were found broadly distributed across the sampled countries, with first reports in many countries. Analysis of genetic diversity confirmed a common origin of geographically distant populations for
G. brimblecombei
and
O. maskelli
, moderate diversity for
T. peregrinus
and
Gonipterus
sp.n.2 and at least two distinct lineages for
L. invasa
. Two divergent haplogroups of
L. invasa
, with overlapping geographic range were confirmed in Ghana, Malawi, Sierra Leone, South Africa and Zimbabwe. Compared to published literature, new haplotypes were detected for
T. peregrinus
,
Gonipterus
sp.n.2 and
L. invasa
, suggesting multiple introduction of those pests in the region. Results of this study will have implications for quarantine, management and future research of
Eucalyptus
insect pests in the region and beyond.
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